Appendix

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The Appendix is intended for use in conjunction with the 2019 Annual Air Quality in Ontario Report. The Appendix briefly describes the provincial Air Quality Health Index (AQHI) network, quality assurance and quality control procedures, and the Ministry of the Environment, Conservation and Parks’ air quality database. It also includes a series of tables displaying station locations and a listing of the summary statistics including means, maximums, percentile values and the number of exceedances of the Ontario Ambient Air Quality Criteria (AAQC) for each pollutant. In addition, trends for select pollutants are displayed for a 10-year period.

Monitoring network operations

Network description

In 2019, the ministry operated 39 ambient air monitoring sites across Ontario as part of the AQHI network. The AQHI network was comprised of 134 continuous monitoring instruments at 39 sites. These instruments have the capability of recording minute data (approximately 70 million data points per year) that are used to scan and validate the continuous hourly data.

Quality assurance and quality control

Day-to-day maintenance and support of the instruments are administered by ministry staff. Instrumentation precision is verified by daily automatic internal zero and span checks. Data analysts and station operators review span control charts to confirm instrument precision using a telemetry system. A quarterly quality assurance and quality control (QA/QC) review is performed on the ambient data set to highlight anomalies and administer corrective action in a timely manner.

The air monitoring station operators routinely inspect and maintain monitoring equipment and stations with mandatory quarterly on-site visits where secondary transfer standards are used to calibrate instrumentation. Station maintenance activities are recorded using FieldWorker Inc. software, an electronic documentation solution; this information is transferred directly to the ministry’s database. The instrumentation used throughout the provincial air monitoring network has been standardized to Thermo Electron Corporation analyzers to streamline parts inventory and leverage common hardware used within each analyzer. The following is a summary of the instrumentation deployed within the network and are all US EPA designated equivalent methods:

Nitrogen Oxides – TE42C/I
Fine Particulate Matter – SHARP 5030
Ozone – TE49C/I
Sulphur Dioxide – TE43I
Carbon Monoxide – TE48I
Total Reduced Sulphur – TE43I/CDN101

The ministry operates a laboratory with gas reference standards that adhere to those of the U.S. National Institute of Standards and Technology (NIST) and the Air Quality Research Division of Environment and Climate Change Canada. The secondary transfer standards used by station operators are referenced and certified to the ministry’s NIST primary standards on a quarterly basis.

The Ontario ambient air quality monitoring network undergoes constant maintenance to ensure a high standard of quality control. Continuous real-time data are consistently reviewed, assessed and validated by ministry staff. Immediate actions are taken to correct any inconsistencies that may affect the validity of the data. These measures ensure ambient air monitoring data are valid, complete, comparable, representative and accurate. As a result, the 2019 ambient air quality monitoring network had 99% valid data from over one million hourly data points.

Data base

The ambient air quality data used in this report are stored in the ministry’s air quality information system (AQUIS) and are made available through the Air Quality Ontario web site, and the Ministry’s Open Data Catalogue web page. A statistical pattern test is used to identify data anomalies, such as unusual pollutant concentrations. Each pollutant has a predetermined concentration range based on historical data. Values outside this range are flagged for further investigation.

Data are obtained from automated ambient air monitoring instruments that operate continuously to produce an average measurement for every hour for a possible total of 8,760 measurements in a given year. Hourly parameters measured include NO/NO₂/NO_x, PM_2.5, O₃, SO₂, CO and TRS compounds. An annual mean requires at least 6,570 hourly readings. In addition, each quarter of the year should have 75% valid data for PM_2.5, whereas for ozone, only the 2^nd and 3^rd quarters of the year require 75% valid data based on protocols that are consistent with the Canadian Council of Ministers of the Environment (CCME) and the United States Environmental Protection Agency (U.S. EPA). For VOC samples, half of the method detection limit (MDL) is applied as appropriate to concentrations measured below the detection limit. An annual or monthly mean for 24-hour VOC samples requires 50% of valid samples.

Network descriptive table

The AQHI network for 2019 is summarized in the 2019 Ontario Continuous Ambient Air Monitoring Network. The table displays the station name, numerical identifier and pollutants measured. The numerical identifier is the station (ID) number, the first digit of which identifies the geographic region in which the station is located. Air monitoring stations within the AQHI network can measure up to six common pollutants (NO₂, PM_2.5, ozone, SO₂, CO and TRS compounds) based on the pollutant(s) of concern for the regional area it represents.

The 2019 Ontario Continuous Ambient Air Monitoring Network also identifies the type of air monitoring site: ambient, road-side, Canadian Ambient Air Quality Standard (CAAQS), and/or National Air Pollution Surveillance (NAPS). Ambient sites represent the general air quality of an area without any direct influence of local industrial sources. Road-side sites are within approximately 100 m of a major roadway with daily traffic volumes greater than 10,000 vehicles per day.

Annual statistics and 10-year trends

The 2019 statistical data and 10-year trends for various continuous pollutants, and selected volatile organic compounds, are provided in 2019 Annual Statistics, and 10-year trends, respectively. The annual averages, maximums and percentiles are displayed in the annual statistics tables. (A percentile is the value equal to or below which a given percentage of the data set falls. For example, if 70% of the data are equal to or below 0.10 ppm, the 70^th percentile is 0.10 ppm).

The 10-year trends are calculated from monthly means through the Mann-Kendall (M-K) test. The M-K test is a nonparametric statistical approach that can be applied to data without making assumptions on the nature of the data distribution. The M-K test is essentially a test for uniform progression (zero change) in the slope of the linear regression of time-ordered data versus time (Gilbert, 1987). The M-K test is particularly suitable for environmental monitoring data since missing, trace and below detection limit values can be handled. This test can also be used to compare trends at multiple stations. The seasonal Kendall test, also performed in this Report, is a generalization of the M-K test (Gilbert, 1987) for use to determine the true trend when there are seasonal cycles in the data which do not constitute a true long-term trend. The 10-year change over time was based on the Sen’s slope, also known as the Thiel-Sen’s estimator of linear trend. The Sen’s slope is closely-related to and applied in conjunction with the M-K Test. Compared to the common least squares regression, the Sen’s slope procedure is a nonparametric method for computing the value of the true slope when there are gross errors or outliers in the data without making assumptions of a normal distribution on the data (Gilbert, 1987).

Other informative tables

Calculated CAAQS metrics for PM_2.5 and ozone are presented for 2019 (based on a three-year average, 2017-2019) and over a 10-year period in Canadian Ambient Air Quality Standard Reporting. The percentage distribution of hourly AQHI readings within the various health risk categories for each of the 39 monitoring sites, and the number of air quality alerts issued in Ontario during 2019 are summarized in AQHI and Air Quality Alert Program Reporting.

2019 air monitoring network

2019 Ontario continuous ambient air monitoring network

ID	Station name	Station location	Year	Latitude	Longtiude	Air intake	Type	AQHI	NO₂	PM_2.5	O₃	SO₂	CO	TRS
12008	Windsor Downtown	467 University Ave. W.	1969	42°18'58.8"	-83°02'37.2"	4	A/RS/C/N	Y	T	T	T	T	T	N/A
12016	Windsor West	College Ave./South St.	1975	42°17'34.4"	-83°04'23.3"	4	A/N	Y	T	T	T	T	N/A	T
13001	Chatham	435 Grand Ave. W.	2005	42°24'13.3"	-82°12'29.9"	15	A/C/N	Y	T	T	T	N/A	N/A	N/A
14111	Sarnia	700 Christina St. N.	2016	42°59’25.0”	-82°23’43.2"	3	A/C/N	Y	T	T	T	T	N/A	T
15020	Grand Bend	Point Blake Conservation Area	1991	43°19'59.1"	-81°44'34.4"	5	A/N	Y	T	T	T	N/A	N/A	N/A
15026	London	42 St. Julien St.	2013	42°58'28.1"	-81°12'03.1"	5	A/C/N	Y	T	T	T	N/A	N/A	N/A
16015	Port Stanley	43665 Dexter Line, Elgin Water T. Plant	2002	42°40'19.5"	-81°09'46.4"	5	A/N	Y	T	T	T	N/A	N/A	N/A
18007	Tiverton	4th Concession/Bruce Rd. 23	1979	44°18'52.1"	-81°32'59.0"	4	A/N	Y	N/A	T	T	N/A	N/A	N/A
21005	Brantford	324 Grand River Ave.	2004	43°08'19.0"	-80°17'33.5"	5	A/C/N	Y	T	T	T	N/A	N/A	N/A
26060	Kitchener	West Ave./Homewood Ave.	1990	43°26'37.8"	-80°30'13.7"	5	A/C/N	Y	T	T	T	N/A	N/A	N/A
27067	St. Catharines	Argyle Cres., Pump Stn.	1987	43°09'36.2"	-79°14'05.1"	4	A/C/N	Y	T	T	T	N/A	N/A	N/A
28028	Guelph	Exhibition St./Clark St. W.	2000	43°33'05.8"	-80°15'51.0"	4	A/C/N	Y	T	T	T	N/A	N/A	N/A
29000	Hamilton Downtown	Elgin St./Kelly St.	1987	43°15'28.0"	-79°51'42.0"	4	A/RS/C/N	Y	T	T	T	T	T	T
29118	Hamilton West	Main St. W./Hwy 403	1985	43°15'26.8"	-79°54'27.9"	3	A/RS/N	Y	T	T	T	N/A	N/A	N/A
29214	Hamilton Mountain	250 Fennell Ave. W.	2019	43°14'28.4"	-79°53'21.9"	3	A/RS/N	Y	T	T	T	T	N/A	N/A
31103	Toronto Downtown*	Bay St./Wellesley St. W.	2000	43°39'46.7"	-79°23'17.2"	10	A/RS/C/N	Y	T	T	T	N/A	N/A	N/A
31129	Toronto Downtown*	55 John St., Metro Hall	2019	43°38'43.5"	-79°23'20.7"	2	A/RS/C/N	Y	T	T	T	N/A	N/A	N/A
33003	Toronto East	Kennedy Rd./Lawrence Ave. E.	1970	43°44'52.5"	-79°16'26.6"	4	A/RS/C/N	Y	T	T	T	N/A	N/A	N/A
34021	Toronto North	4905 Dufferin St., ECCC	1988	43°46'53.8"	-79°25'03.8"	5	A/RS/C/N	Y	T	T	T	T	T	N/A
35125	Toronto West	125 Resources Rd.	2003	43°42'34.0"	-79°32'36.6"	8	A/RS/C/N	Y	T	T	T	T	T	N/A
44008	Burlington	North Shore Blvd. E./Lakeshore Rd.	1979	43°18'54.4"	-79°48'09.5"	5	A/C/N	Y	T	T	T	N/A	N/A	N/A
44017	Oakville	Eighth Line/Glenashton Dr., Halton Reservoir	2003	43°29'12.9"	-79°42'08.2"	12	A/C/N	Y	T	T	T	N/A	N/A	N/A
44029	Milton	1120 Main St. E.	2019	43°31'46.7"	-79°51'44.8"	4	A/C/N	Y	T	T	T	T	N/A	N/A
45027	Oshawa	Brittania Ave. W., Ep Taylor Stables	2005	43°57'07.5"	-78°54'45.2"	7	A/C/N	Y	T	T	T	N/A	N/A	N/A
46090	Brampton	109 Mclaughlin Rd. S.	2000	43°41'55.5"	-79°46'51.3"	5	A/C/N	Y	T	T	T	N/A	N/A	N/A
46108	Mississauga	3359 Mississauga Rd. N., U of T Campus	2007	43°32'49.1"	-79°39'31.3"	5	A/C/N	Y	T	T	T	N/A	N/A	N/A
47045	Barrie	83 Perry St.	2001	44°22'56.5"	-79°42'08.3"	5	A/C/N	Y	T	T	T	N/A	N/A	N/A
48006	Newmarket	Eagle St. W./Mccaffrey Rd.	2001	44°02'39.5"	-79°28'59.7"	5	A/N	Y	T	T	T	N/A	N/A	N/A
49005	Parry Sound	7 Bay St.	2001	45°20'16.3"	-80°02'17.4"	5	A/N	Y	T	T	T	N/A	N/A	N/A
49010	Dorset	1026 Bellwood Acres Rd.	1981	45°13'27.4"	-78°55'58.6"	3	A/N	Y	N/A	T	T	N/A	N/A	N/A
51001	Ottawa Downtown	Rideau St./Wurtemburg St.	1971	45°26'03.6"	-75°40'33.6"	4	A/C/N	Y	T	T	T	T	T	N/A
51010	Petawawa	Petawawa Research Forest Facility	2007	45°59'48.2"	-77°26'28.3"	6	A/N	Y	N/A	T	T	N/A	N/A	N/A
52023	Kingston	23 Beechgrove Lane	2014	44°13'11.5"	-76°31'16.1"	5	A/C/N	Y	T	T	T	N/A	N/A	N/A
54012	Belleville	2 Sidney St., Water Treatment Plant	2002	44°09'01.9"	-77°23'43.8"	10	A/N	Y	T	T	T	N/A	N/A	N/A
56051	Cornwall	Bedford St./3rd St. W.	1970	45°01'04.7"	-74°44'06.8"	4	A/N	Y	T	T	T	N/A	N/A	N/A
59006	Peterborough	10 Hospital Dr.	1998	44°18'06.9"	-78°20'46.4"	10	A/C/N	Y	T	T	T	N/A	N/A	N/A
63203	Thunder Bay	421 James St. S.	2004	48°22'45.8"	-89°17'24.6"	15	A/RS/C/N	Y	T	T	T	N/A	N/A	N/A
71078	Sault Ste. Marie	Sault College	2004	46°31'59.5"	-84°18'35.7"	8	A/C/N	Y	T	T	T	T	N/A	T
75010	North Bay	Chippewa St. W., Dept. National Defence	1979	46°19'23.5"	-79°26'57.4"	4	A/RS/N	Y	T	T	T	N/A	N/A	N/A
77233	Sudbury	155 Elm St.	2013	46°29'31.0"	-81°00'11.2"	3	A/C/N	Y	T	T	T	T	N/A	N/A
81103	Toronto Downtown*	185 College St., Wallberg Bldg, U OF T	2019	43°39'46.7"	-79°23'17.2"	17	A/C/N	Y	T	T	T	N/A	N/A	N/A
Total								39	36	39	39	11	5	4

Notes:

ID: station identfication number
Year: year station began monitoring
Air intake: height of air intake above ground (m)
Type: type of monitoring site
A: ambient
RS: road-side
C: Canadian Ambient Air Quality Standard (CAAQS)
N: National Air Pollution Surveillance (NAPS)
AQHI: Air Quality Health Index
T: telemetry
NO₂: nitrogen dioxide
PM_2.5: fine particulate matter
O₃: ground-level ozone
SO₂: sulphur dioxide
CO: carbon monoxide
TRS: total reduced sulphur
Y: yes

*Toronto Downtown was relocated on two occasions in 2019 and should be counted as one station.

2019 annual statistics

2019 nitric oxide (NO) annual statistics

Unit: parts per billion (ppb)

ID	City	Location	Valid h	10%	30%	50%	70%	90%	99%	Mean	Max 1h	Max 24h
12008	Windsor Downtown	467 University Ave. W.	8475	0.1	0.5	1.0	1.8	5.0	34.9	2.68	164.8	64.5
12016	Windsor West	College Ave./South St.	8640	0.2	0.3	0.7	1.6	5.2	52.8	3.06	161.2	63.4
13001	Chatham	435 Grand Ave. W.	8747	0.0	0.1	0.4	1.0	3.4	14.8	1.36	75.4	23.5
14111	Sarnia	700 Christina St. N.	8673	0.4	0.6	0.9	1.3	3.1	16.5	1.72	76.0	11.7
15020	Grand Bend	Point Blake Conservation Area	8553	0.0	0.1	0.2	0.3	0.6	2.4	0.28	9.2	2.4
15026	London	42 St. Julien St.	8684	0.0	0.1	0.2	0.5	1.7	11.7	0.87	77.0	10.8
16015	Port Stanley	43665 Dexter Line, Elgin Water T. Plt	8674	0.0	0.1	0.1	0.3	0.9	3.6	0.39	31.1	4.3
21005	Brantford	324 Grand River Ave.	8659	0.0	0.1	0.2	0.5	1.9	11.3	0.92	49.4	8.0
26060	Kitchener	West Ave./Homewood Ave.	8711	0.0	0.2	0.3	0.6	2.0	21.0	1.19	107.6	20.8
27067	St. Catharines	Argyle Cres., Pump Stn.	8677	0.0	0.2	0.4	0.7	1.9	16.9	1.16	74.8	10.2
28028	Guelph	Exhibition St./Clark St. W.	8692	0.0	0.1	0.2	0.5	1.6	14.6	0.93	68.4	14.0
29000	Hamilton Downtown	Elgin St./Kelly St.	8739	0.2	0.5	1.3	2.9	9.7	40.9	3.99	105.6	37.7
29118	Hamilton West	Main St. W./Hwy 403	8689	0.3	0.8	1.4	2.8	10.2	43.2	4.15	124.7	33.5
29214	Hamilton Mountain	250 Fennell Ave. W.	8747	0.0	0.2	0.6	1.0	4.2	22.5	1.83	111.0	19.8
31103	Toronto Downtown	Bay St./Wellesley St. W.	2783	0.0	0.4	1.0	1.8	4.3	21.4	INS	89.5	17.3
31129	Toronto Downtown	55 John St.	4602	1.4	2.7	4.4	7.9	16.4	50.2	INS	162.4	36.4
33003	Toronto East	Kennedy Rd./Lawrence Ave. E.	8665	0.2	0.6	1.3	2.6	6.6	42.2	3.42	164.4	33.9
34021	Toronto North	4905 Dufferin St., ECCC	8652	0.0	0.3	0.6	1.5	5.3	36.8	2.70	152.3	38.1
35125	Toronto West	125 Resources Rd.	8583	0.2	1.2	2.8	6.2	17.5	70.9	7.50	278.1	69.8
44008	Burlington	North Shore Blvd. E./Lakeshore Rd.	8730	0.4	0.7	1.2	2.3	6.5	30.3	2.95	112.9	19.8
44017	Oakville	Eighth Line/Glenashton Dr., Halton Res.	8685	0.1	0.2	0.4	0.9	3.9	26.8	1.84	337.4	25.8
44029	Milton	1120 Main St. E.	8575	0.4	1.0	1.2	2.0	6.0	45.8	3.62	163.0	33.6
45027	Oshawa	Brittania Ave. W., EP Taylor Stables	8734	0.1	0.3	0.4	0.8	1.6	8.4	0.88	35.8	7.2
46090	Brampton	109 McLaughlin Rd. S.	8662	0.0	0.1	0.2	0.8	4.1	39.5	2.17	147.8	30.2
46108	Mississauga	3359 Mississauga Rd. N., U of T Campus	8740	0.1	0.2	0.4	0.9	5.5	43.8	2.57	127.0	32.3
47045	Barrie	83 Perry St.	8733	0.0	0.3	0.7	1.6	3.5	29.3	2.18	169.1	24.2
48006	Newmarket	Eagle St. W./McCaffrey Rd.	8659	0.2	0.3	0.4	0.7	2.3	18.6	1.31	104.2	13.5
49005	Parry Sound	7 Bay St.	8676	0.1	0.2	0.3	0.5	1.4	6.9	0.72	41.4	5.7
51001	Ottawa Downtown	Rideau St./Wurtemburg St.	8712	0.3	0.6	0.8	1.2	2.8	15.8	1.61	70.7	15.1
52023	Kingston	23 Beechgrove Lane	8686	0.0	0.1	0.2	0.5	1.2	5.2	0.55	71.7	11.5
54012	Belleville	2 Sidney St., Water Treatment Plant	8742	0.2	0.2	0.4	0.7	3.0	15.1	1.29	58.1	10.7
56051	Cornwall	Bedford St./3rd St. W.	8691	0.2	0.3	0.5	0.8	1.9	24.1	1.52	130.7	21.7
59006	Peterborough	10 Hospital Dr.	8678	0.3	0.6	0.7	1.0	2.0	13.0	1.23	54.0	9.0
63203	Thunder Bay	421 James St. S.	8491	0.6	1.0	1.6	2.6	8.9	35.0	3.79	86.3	20.8
71078	Sault Ste. Marie	Sault College	8632	0.2	0.4	0.7	1.3	3.4	11.5	1.48	58.8	14.1
75010	North Bay	Chippewa St. W., Dept. National Defence	8717	0.3	0.5	0.7	1.2	3.0	22.6	1.79	99.1	19.5
77233	Sudbury	155 Elm St.	8603	0.3	0.6	1.0	1.8	4.6	37.7	2.77	151.1	37.2
81103	Toronto Downtown	Wallberg Building U of T	1191	0.4	0.7	1.2	2.3	6.3	31.7	INS	69.8	16.5

2019 nitrogen dioxide (NO₂) annual statistics

Unit: parts per billion (ppb)
NO₂ 1h AAQC: 200 ppb
NO₂ 24h AAQC: 100 ppb

ID	City	Location	Valid h	10%	30%	50%	70%	90%	99%	Mean	Max 1h	Max 24h
12008	Windsor Downtown	467 University Ave. W.	8475	4.0	6.3	8.9	12.2	20.5	38.8	10.94	56.5	34.4
12016	Windsor West	College Ave./South St.	8640	3.1	5.4	8.0	11.2	19.1	40.0	9.98	60.0	32.4
13001	Chatham	435 Grand Ave. W.	8747	1.9	3.2	4.5	6.4	11.0	25.1	5.84	45.8	28.0
14111	Sarnia	700 Christina St. N.	8673	0.9	2.6	4.8	8.2	15.4	29.5	6.80	47.2	24.5
15020	Grand Bend	Point Blake Conservation Area	8553	0.3	1.1	1.9	3.0	5.4	10.6	2.49	17.2	11.1
15026	London	42 St. Julien St.	8684	1.8	3.1	4.3	6.3	11.0	27.2	5.76	45.3	24.9
16015	Port Stanley	43665 Dexter Line, Elgin Water T. Plt	8674	0.8	1.6	2.4	3.5	6.0	11.9	3.02	23.6	9.8
21005	Brantford	324 Grand River Ave.	8658	2.0	2.9	4.0	6.0	11.1	24.0	5.57	41.5	24.2
26060	Kitchener	West Ave./Homewood Ave.	8711	1.8	2.9	4.4	6.7	12.7	31.7	6.25	57.6	26.1
27067	St. Catharines	Argyle Cres., Pump Stn.	8677	1.8	2.9	4.3	6.5	12.3	27.4	5.97	43.4	21.0
28028	Guelph	Exhibition St./Clark St. W.	8692	1.2	2.4	3.8	6.0	11.7	27.5	5.44	43.7	22.2
29000	Hamilton Downtown	Elgin St./Kelly St.	8737	4.0	6.6	9.9	15.4	24.4	40.0	12.49	58.2	36.5
29118	Hamilton West	Main St. W./Hwy 403	8685	3.5	5.8	8.6	13.4	22.7	38.7	11.29	58.4	38.0
29214	Hamilton Mountain	250 Fennell Ave. W.	8747	2.1	4.0	6.0	10.0	20.0	36.0	8.81	57.0	35.3
31103	Toronto Downtown	Bay St./Wellesley St. W.	2783	3.9	7.3	10.8	15.3	25.1	45.3	INS	53.0	31.0
31129	Toronto Downtown	55 John St.	4602	6.1	9.3	12.6	16.7	25.0	37.9	INS	66.9	32.3
33003	Toronto East	Kennedy Rd./Lawrence Ave. E.	8664	2.6	4.9	7.5	11.8	21.6	42.6	10.24	78.3	33.7
34021	Toronto North	4905 Dufferin St., ECCC	8649	2.8	4.8	7.5	12.1	22.2	42.7	10.51	70.1	33.4
35125	Toronto West	125 Resources Rd.	8583	4.5	8.3	12.3	17.6	28.0	47.1	14.62	75.9	38.7
44008	Burlington	North Shore Blvd. E./Lakeshore Rd.	8728	2.4	4.6	7.1	11.2	20.7	37.2	9.61	53.2	31.3
44017	Oakville	Eighth Line/Glenashton Dr., Halton Res.	8684	2.4	4.1	6.5	10.4	19.4	38.8	9.08	58.1	33.9
44029	Milton	1120 Main St. E.	8569	2.0	4.0	6.0	9.8	20.2	39.0	8.86	57.0	32.9
45027	Oshawa	Brittania Ave. W., EP Taylor Stables	8734	0.7	1.3	2.2	3.8	8.0	17.4	3.50	38.9	16.4
46090	Brampton	109 McLaughlin Rd. S.	8662	1.6	3.1	5.6	9.8	20.1	40.0	8.59	62.3	35.7
46108	Mississauga	3359 Mississauga Rd. N., U of T Campus	8737	2.1	3.7	6.0	9.8	17.6	37.3	8.40	52.3	30.6
47045	Barrie	83 Perry St.	8733	1.7	2.8	4.0	6.7	14.0	32.8	6.34	56.0	25.2
48006	Newmarket	Eagle St. W./McCaffrey Rd.	8659	1.0	2.0	3.3	5.7	12.5	33.3	5.47	55.0	26.1
49005	Parry Sound	7 Bay St.	8676	0.6	1.0	1.5	2.5	5.5	18.9	2.64	34.8	12.5
51001	Ottawa Downtown	Rideau St./Wurtemburg St.	8712	1.6	2.8	4.4	7.4	14.7	32.5	6.70	51.2	26.9
52023	Kingston	23 Beechgrove Lane	8683	1.1	1.8	2.6	4.1	8.5	22.0	4.01	50.3	19.6
54012	Belleville	2 Sidney St., Water Treatment Plant	8743	1.1	1.8	2.7	4.4	9.2	24.2	4.24	41.4	17.2
56051	Cornwall	Bedford St./3rd St. W.	8691	1.2	2.0	3.1	5.1	10.8	30.2	5.03	49.4	28.3
59006	Peterborough	10 Hospital Dr.	8678	0.6	1.4	2.4	4.0	8.5	25.4	3.90	43.3	18.2
63203	Thunder Bay	421 James St. S.	8491	1.7	2.9	4.4	7.2	14.6	31.6	6.65	49.2	25.2
71078	Sault Ste. Marie	Sault College	8632	1.1	1.8	2.8	4.7	10.3	22.6	4.47	46.8	20.8
75010	North Bay	Chippewa St. W., Dept. National Defence	8717	1.0	1.6	2.6	4.6	11.7	36.6	5.11	53.8	27.0
77233	Sudbury	155 Elm St.	8603	1.6	2.7	4.2	6.8	15.3	41.4	6.88	56.8	29.5
81103	Toronto Downtown	Wallberg Building U of T	1191	3.2	5.1	7.4	10.2	18.1	32.7	INS	37.1	22.2

2019 nitrogen oxides (NO_x) annual statistics

Unit: parts per billion (ppb)

ID	City	Location	Valid h	10%	30%	50%	70%	90%	99%	Mean	Max 1h	Max 24h
12008	Windsor Downtown	467 University Ave. W.	8475	4.5	7.3	10.2	14.2	25.6	67.4	13.6	200.4	93.8
12016	Windsor West	College Ave./South St.	8640	3.6	6.2	8.9	13.0	23.7	86.8	13.0	211.2	90.8
13001	Chatham	435 Grand Ave. W.	8747	2.0	3.5	5.2	7.7	13.9	34.2	7.2	117.1	47.6
14111	Sarnia	700 Christina St. N.	8673	1.5	3.4	5.8	9.7	18.4	42.4	8.5	120.0	33.8
15020	Grand Bend	Point Blake Conservation Area	8553	0.3	1.1	2.0	3.2	5.9	12.1	2.7	23.1	12.6
15026	London	42 St. Julien St.	8684	2.0	3.4	4.8	6.9	12.6	37.3	6.6	116.7	35.6
16015	Port Stanley	43665 Dexter Line, Elgin Water T. Plt	8674	0.9	1.7	2.6	3.8	6.7	15.5	3.4	51.7	12.1
21005	Brantford	324 Grand River Ave.	8659	2.2	3.1	4.4	6.7	13.4	31.6	6.5	74.8	28.9
26060	Kitchener	West Ave./Homewood Ave.	8711	2.0	3.2	4.8	7.5	14.6	47.1	7.4	157.6	45.8
27067	St. Catharines	Argyle Cres., Pump Stn.	8677	2.1	3.3	4.7	7.2	14.5	40.1	7.1	111.4	28.3
28028	Guelph	Exhibition St./Clark St. W.	8692	1.5	2.6	4.1	6.5	13.2	38.7	6.4	108.1	36.0
29000	Hamilton Downtown	Elgin St./Kelly St.	8739	4.4	7.6	11.6	18.3	34.7	75.3	16.5	156.5	71.8
29118	Hamilton West	Main St. W./Hwy 403	8686	4.2	7.0	10.3	16.7	32.5	76.1	15.4	167.1	71.5
29214	Hamilton Mountain	250 Fennell Ave. W.	8747	2.4	4.2	7.0	11.3	24.0	52.9	10.7	164.0	55.1
31103	Toronto Downtown	Bay St./Wellesley St. W.	2783	4.0	8.2	12.1	17.2	28.8	64.6	INS	140.2	47.7
31129	Toronto Downtown	55 John St.	4602	8.1	12.7	17.8	24.5	39.1	85.3	INS	229.3	68.7
33003	Toronto East	Kennedy Rd./Lawrence Ave. E.	8665	3.1	6.0	9.2	14.3	27.4	78.2	13.7	228.0	63.6
34021	Toronto North	4905 Dufferin St., ECCC	8652	3.3	5.5	8.6	13.8	28.1	72.7	13.2	214.3	70.0
35125	Toronto West	125 Resources Rd.	8583	5.5	10.5	15.9	23.6	45.1	109.5	22.1	353.9	106.0
44008	Burlington	North Shore Blvd. E./Lakeshore Rd.	8730	3.0	5.6	8.7	13.6	26.2	62.5	12.6	161.7	49.3
44017	Oakville	Eighth Line/Glenashton Dr., Halton Res.	8685	2.7	4.5	7.1	11.5	22.9	62.3	10.9	386.9	59.6
44029	Milton	1120 Main St. E.	8575	3.0	5.0	7.6	12.0	27.0	79.6	12.5	217.0	65.1
45027	Oshawa	Brittania Ave. W., EP Taylor Stables	8734	1.0	1.8	2.8	4.6	9.6	23.2	4.4	61.3	22.6
46090	Brampton	109 McLaughlin Rd. S.	8662	1.8	3.3	6	10.9	24.1	75.4	10.74	206.1	65.8
46108	Mississauga	3359 Mississauga Rd. N., U of T Campus	8740	2.5	4.2	6.6	11	23.4	75.1	10.97	177.8	62.9
47045	Barrie	83 Perry St.	8733	2	3.4	5	7.8	18	56.3	8.52	207.8	45.0
48006	Newmarket	Eagle St. W./McCaffrey Rd.	8659	1.3	2.4	3.9	6.6	14.8	49.0	6.78	126.5	35.7
49005	Parry Sound	7 Bay St.	8676	0.8	1.4	2	3.1	6.7	23.4	3.34	58.5	17.2
51001	Ottawa Downtown	Rideau St./Wurtemburg St.	8712	2.2	3.6	5.4	8.7	17.2	46.5	8.31	102.3	42.0
52023	Kingston	23 Beechgrove Lane	8686	1.1	1.9	2.9	4.6	9.4	26.9	4.55	122.0	31.0
54012	Belleville	2 Sidney St., Water Treatment Plant	8742	1.4	2.1	3.2	5.4	11.7	36.5	5.53	83.1	21.4
56051	Cornwall	Bedford St./3rd St. W.	8691	1.5	2.5	3.7	6	12.9	51.8	6.54	170.7	41.9
59006	Peterborough	10 Hospital Dr.	8678	1.2	2	3.1	5	10.5	34.8	5.14	91.1	25.0
63203	Thunder Bay	421 James St. S.	8491	2.7	4.2	6.3	10.3	22.9	59.9	10.44	123.6	44.5
71078	Sault Ste. Marie	Sault College	8632	1.5	2.4	3.6	6	13.7	31.1	5.95	105.4	34.8
75010	North Bay	Chippewa St. W., Dept. National Defence	8717	1.3	2.2	3.5	5.9	14.5	55.9	6.91	145.3	46.5
77233	Sudbury	155 Elm St.	8603	2.1	3.5	5.4	8.7	19.8	75.5	9.65	187.8	66.6
81103	Toronto Downtown	Wallberg Building U of T	1191	3.9	6.3	8.8	12.9	23.7	58.8	INS	105.8	38.6

2019 fine particulate matter (PM_2.5) annual statistics

Unit: micrograms per cubic metre (μg/m³)
PM_2.5 24h reference level: 28 μg/m³

ID	City	Location	Valid h	10%	30%	50%	70%	90%	99%	Mean	Max 1h	Max 24h	Number of times above 24h reference level
12008	Windsor Downtown	467 University Ave. W.	8488	3	4	6	9	15	28	7.8	48	27	0
12016	Windsor West	College Ave./South St.	8620	3	5	8	11	17	32	9.1	54	38	3
13001	Chatham	435 Grand Ave. W.	8718	2	3	5	9	14	24	6.8	41	27	0
14111	Sarnia	700 Christina St. N.	8719	1	3	5	9	16	28	7.1	57	31	1
15020	Grand Bend	Point Blake Conservation Area	8541	2	2	4	6	11	20	5.4	40	23	0
15026	London	42 St. Julien St.	8746	2	3	5	8	14	26	6.7	55	26	0
16015	Port Stanley	43665 Dexter Line, Elgin Water T. Plt	8697	1	3	5	8	14	25	6.7	42	22	0
18007	Tiverton	4th Concession/Bruce Rd. 23	8640	1	2	4	6	11	21	5.0	42	21	0
21005	Brantford	324 Grand River Ave.	8729	2	4	6	9	15	29	7.4	91	28	0
26060	Kitchener	West Ave./Homewood Ave.	8725	2	3	6	8	15	28	7.2	56	31	1
27067	St. Catharines	Argyle Cres., Pump Stn.	8625	2	3.9	5	8	14	26	7.0	50	25	0
28028	Guelph	Exhibition St./Clark St. W.	8723	1	3	5	9	16	29	7.1	55	29	1
29000	Hamilton Downtown	Elgin St./Kelly St.	8646	2	5	7	11	18	30	8.8	67	29	2
29118	Hamilton West	Main St. W./Hwy 403	8726	2	4	6	9	16	28	7.8	50	26	0
29214	Hamilton Mountain	250 Fennell Ave. W.	8678	2	4	6	9	16	31	7.9	61	28	0
31103	Toronto Downtown	Bay St./Wellesley St. W.	2852	2	4	6	9	16	28	INS	55	29	1
31129	Toronto Downtown	55 John St.	4582	3	5	7	9	15	29	INS	44	25	0
33003	Toronto East	Kennedy Rd./Lawrence Ave. E.	8748	2	4	6	8	14	26	7.0	51	31	1
34021	Toronto North	4905 Dufferin St., ECCC	8626	1	3	5	8	14	28	6.8	52	32	1
35125	Toronto West	125 Resources Rd.	8688	2	4	6	8	14	25	7.2	72	25	0
44008	Burlington	North Shore Blvd. E./Lakeshore Rd.	8730	2	3	6	8	15	25	7.0	55	29	1
44017	Oakville	Eighth Line/Glenashton Dr., Halton Res.	8621	2	4	6	9	14	26	7.2	52	28	0
44029	Milton	1120 Main St. E.	8530	2	4	6	9	15	27	7.5	44	27	0
45027	Oshawa	Brittania Ave. W., EP Taylor Stables	8667	2	3	5	7	12	26	6.1	55	28	0
46090	Brampton	109 McLaughlin Rd. S.	8720	2	3	5	8	14	26	6.8	47	26	0
46108	Mississauga	3359 Mississauga Rd. N., U of T Campus	8697	1	3	5	9	15	26	7.0	47	29	1
47045	Barrie	83 Perry St.	8510	2	3	5	9	16	30	7.5	51	34	2
48006	Newmarket	Eagle St. W./McCaffrey Rd.	8682	1	2	4	7	13	25	5.9	43	26	0
49005	Parry Sound	7 Bay St.	8612	1	2	3	5	9	21	4.4	51	21	0
49010	Dorset	1026 Bellwood Acres Rd.	8689	1	2	3	5	9	18	4.1	34	20	0
51001	Ottawa Downtown	Rideau St./Wurtemburg St.	8517	2	3	5	7	12	23	5.9	39	29	1
51010	Petawawa	Petawawa Research Forest Facility	8623	1	2	3	5	7	14	3.8	29	14	0
52023	Kingston	23 Beechgrove Lane	8735	1	3	4	6	11	22	5.4	59	26	0
54012	Belleville	2 Sidney St., Water Treatment Plant	8586	2	3	4	7	13	25	6.1	45	31	1
56051	Cornwall	Bedford St./3rd St. W.	8702	2	3	5	7	11	23	5.9	67	25	0
59006	Peterborough	10 Hospital Dr.	8730	1	3	4	7	13	25	6.0	48	28	0
63203	Thunder Bay	421 James St. S.	8702	1	3	4	6	10	22	5.1	70	24	0
71078	Sault Ste. Marie	Sault College	8652	1	2	4	5	10	20	4.8	55	19	0
75010	North Bay	Chippewa St. W., Dept. National Defence	8711	1	2	4	5	9	17	4.5	59	19	0
77233	Sudbury	155 Elm St.	8706	1	2	4	6	10	22	5.0	75	22	0
81103	Toronto Downtown	Wallberg Building U of T	1236	1	3	5	8	15	26	INS	46	18	0

Notes

Measurements taken by SHARP 5030.
The PM_2.5 24-hour reference level of 28 µg/m³ is based on the 24-hour PM_2.5 Canadian Ambient Air Quality Standard (CAAQS) established in 2015.

2019 ground-level ozone (O₃) annual statistics

Unit: parts per billion (ppb)
O₃ 1h AAQC: 80 ppb

ID	City	Location	Valid h	10%	30%	50%	70%	90%	99%	Mean	Max 1h	Max 24h	Number of times above 1h criterion
12008	Windsor Downtown	467 University Ave. W.	8512	11	20	26	32	42	60	26.6	82	55	1
12016	Windsor West	College Ave./South St.	8635	10	20	27	34	44	61	27.3	80	49	0
13001	Chatham	435 Grand Ave. W.	8724	14	23	29	35	44	59	29.2	76	53	0
14111	Sarnia	700 Christina St. N.	8675	14	23	29	36	45	62	29.2	87	56	4
15020	Grand Bend	Point Blake Conservation Area	8528	17	26	32	37	45	60	31.6	85	53	7
15026	London	42 St. Julien St.	8694	9	21	27	33	43	55.1	26.8	70	49	0
16015	Port Stanley	43665 Dexter Line, Elgin Water T. Plt	8666	17	26	32	38	48	61	32.3	77	56	0
18007	Tiverton	4th Concession/Bruce Rd. 23	8694	18	25	31	37	43	56	31.1	81	54	1
21005	Brantford	324 Grand River Ave.	8680	10	21	28	34	44	56	27.5	74	49	0
26060	Kitchener	West Ave./Homewood Ave.	8697	11	21	27	33	43	55	27.2	77	47	0
27067	St. Catharines	Argyle Cres., Pump Stn.	8704	12	23	29	35	43	56	28.4	70	48	0
28028	Guelph	Exhibition St./Clark St. W.	8690	11	21	27	33	41	53	26.3	74	47	0
29000	Hamilton Downtown	Elgin St./Kelly St.	8677	7	18	24	31	40	53.3	24.4	65	47	0
29118	Hamilton West	Main St. W./Hwy 403	8689	4	17	24	31	40	52	23.6	65	46	0
29214	Hamilton Mountain	250 Fennell Ave. W.	8747	12	21	27	33	43	56	27.5	70	51	0
31103	Toronto Downtown	Bay St./Wellesley St. W.	2827	13	22	28	34	40	49	INS	INS	INS	0
31129	Toronto Downtown	55 John St.	4589	7	15	20	25	37	55	INS	76	46	0
33003	Toronto East	Kennedy Rd./Lawrence Ave. E.	8667	9	19	25	31	39	51	24.6	67	47	0
34021	Toronto North	4905 Dufferin St., ECCC	8585	7	17	24	31	40	53	24.1	77	43	0
35125	Toronto West	125 Resources Rd.	8463	4	15	22	28	38	55	21.8	77	44	0
44008	Burlington	North Shore Blvd. E./Lakeshore Rd.	8694	9	20	27	34	42	56	26.6	74	47	0
44017	Oakville	Eighth Line/Glenashton Dr., Halton Res.	8685	11	21	27	33	42	56	27.1	71	50	0
44029	Milton	1120 Main St. E.	8573	8	21	27	34	43	58	26.9	77	50	0
45027	Oshawa	Brittania Ave. W., EP Taylor Stables	8706	9	20	25	30	37	51	24.4	66	40	0
46090	Brampton	109 McLaughlin Rd. S.	8611	9	20	27	33	42	55	26.5	72	49	0
46108	Mississauga	3359 Mississauga Rd. N., U of T Campus	8717	5	18	25	32	40.5	53	24.5	65	48	0
47045	Barrie	83 Perry St.	8712	9	20	26	33	40	51	25.7	75	47	0
48006	Newmarket	Eagle St. W./McCaffrey Rd.	8642	13	22	28	34	41	54	27.8	88	48	4
49005	Parry Sound	7 Bay St.	8682	16	25	30	36	43	54	29.8	68	48	0
49010	Dorset	1026 Bellwood Acres Rd.	8671	10	22	28	35	42	52	27.5	64	47	0
51001	Ottawa Downtown	Rideau St./Wurtemburg St.	8725	11	20	26	32	39	49	25.9	57	46	0
51010	Petawawa	Petawawa Research Forest Facility	8746	12	22	28	34	41	49	27.3	58	47	0
52023	Kingston	23 Beechgrove Lane	8680	16	25	30	35	43	55	29.9	68	51	0
54012	Belleville	2 Sidney St., Water Treatment Plant	8743	15	24	30	35	43	56	29.6	73	51	0
56051	Cornwall	Bedford St./3rd St. W.	8686	12	22	28	33	40	50	26.9	58	46	0
59006	Peterborough	10 Hospital Dr.	8684	14	23	28	34	42	53	28.3	68	48	0
63203	Thunder Bay	421 James St. S.	8695	8	18	24	30	37	48	23.7	56	47	0
71078	Sault Ste. Marie	Sault College	8652	15	23	28	34	41	51	28.1	61	50	0
75010	North Bay	Chippewa St. W., Dept. National Defence	8722	11	21	27	32	40	50	26.4	63	46	0
77233	Sudbury	155 Elm St.	8607	12	21	27	32	39	49	26.3	75	46	0
81103	Toronto Downtown	Wallberg Building U of T	1191	14	25	31	36	43	54	INS	64	44	0

2019 sulphur dioxide (SO₂) annual statistics

Unit: parts per billion (ppb)
SO₂ 10 min AAQC: 67 ppb
SO₂ 1h AAQC: 40 ppb
SO₂ 1y AAQC: 4 ppb

ID	City	Location	Valid h	10%	30%	50%	70%	90%	99%	Mean	Max 1h	Max 24h	Number of times above 10 min criteria	Number of times above 1h criteria	Number of times above annual criteria
12008	Windsor Downtown	467 University Ave. W.	8514	0.0	0.0	0.1	0.2	1.0	6.2	0.44	21.8	6.7	0	0	0
12016	Windsor West	College Ave./South St.	8042	0.0	0.1	0.3	0.6	1.9	8.4	0.82	31.7	7.9	0	0	0
14111	Sarnia	700 Christina St. N.	8697	0.0	0.1	0.3	0.6	3.7	32.7	1.93	69.4	30.2	37	47	0
29000	Hamilton Downtown	Elgin St./Kelly St.	8706	0.2	0.4	0.7	2.0	15.4	52.1	4.75	123.7	45.9	269	185	1
29214	Hamilton Mountain	250 Fennell Ave. W.	8532	0.1	0.3	0.5	1.7	10.2	40.4	3.47	68.7	42.1	40	88	0
34021	Toronto North	4905 Dufferin St., ECCC	8617	0.0	0.0	0.0	0.1	0.3	2.0	0.15	8.6	1.6	0	0	0
35125	Toronto West	125 Resources Rd.	8458	0.0	0.1	0.1	0.2	0.5	2.5	0.27	11.8	2.3	0	0	0
44029	Milton	1120 Main St. E.	4654	0.5	0.7	0.9	1.0	2.0	5.6	INS	14.9	3.7	0	0	0
51001	Ottawa Downtown	Rideau St./Wurtemburg St.	8733	0.1	0.1	0.1	0.2	0.3	0.7	0.17	2.7	0.6	0	0	0
71078	Sault Ste. Marie	Sault College	8607	0.0	0.1	0.1	0.2	0.8	14.4	0.70	52.0	10.9	7	6	0
77233	Sudbury	155 Elm St.	8596	0.1	0.1	0.2	0.5	2.7	15.6	1.15	93.8	8.3	18	6	0

2019 carbon monoxide (CO) annual statistics

Unit: parts per million (ppm)
CO 1h AAQC: 30 ppm
CO 8h AAQC: 13 ppm

ID	City	Location	Valid h	10%	30%	50%	70%	90%	99%	Mean	Max 1h	Max 8h
12008	Windsor Downtown	467 University Ave. W.	8195	0.16	0.18	0.21	0.24	0.34	0.70	0.24	2.33	1.328
29000	Hamilton Downtown	Elgin St./Kelly St.	8616	0.14	0.17	0.21	0.27	0.41	0.69	0.25	1.89	0.95
34021	Toronto North	4905 Dufferin St., ECCC	8493	0.14	0.16	0.19	0.22	0.30	0.47	0.20	1.03	0.71
35125	Toronto West	125 Resources Rd.	8506	0.16	0.19	0.22	0.26	0.35	0.62	0.24	1.49	0.89
51001	Ottawa Downtown	Rideau St./Wurtemburg St.	8688	0.12	0.15	0.17	0.20	0.25	0.41	0.18	0.68	0.54

2019 total reduced sulphur (TRS) compounds annual statistics

Unit: parts per billion (ppb)

ID	City	Location	Valid h	90%	99%	Mean	Max 1h	Max 24h
12016	Windsor West	College Ave./South St.	8604	0	2	0.09	8	1
14111	Sarnia	700 Christina St. N.	8694	0	1	0.04	2	1
29000	Hamilton Downtown	Elgin St./Kelly St.	8738	0	1	0.06	9	1
71078	Sault Ste. Marie	Sault College	8559	1	1	0.28	5	1

2019 benzene annual statistics

Unit: micrograms per cubic metre (μg/m³)
Benzene 24h AAQC: 2.3 μg/m³
Benzene annual AAQC: 0.45 μg/m³

ID	City	Location	Number of samples	10%	25%	50%	75%	90%	Max	Min	Mean	Standard deviation	Number of times above annual criteria
12016	Windsor West	College Ave./South St.	54	0.265	0.315	0.380	0.505	0.672	1.586	0.223	0.445	0.217	0
14111	Sarnia	700 Christina St.	57	0.100	0.242	0.335	0.545	0.739	2.047	0.100	0.419	0.319	0
15026	London	42 St. Julien St.	54	0.100	0.218	0.292	0.376	0.450	0.578	0.100	0.296	0.118	0
26060	Kitchener	West Ave./Homewood Ave.	57	0.100	0.212	0.291	0.380	0.461	0.692	0.100	0.290	0.147	0
29000	Hamilton Downtown	Elgin St./Kelly St.	59	0.222	0.316	0.411	0.657	1.129	2.070	0.100	0.568	0.427	1
34021	Toronto North	4905 Dufferin St., ECCC	50	0.100	0.231	0.333	0.405	0.602	0.935	0.100	0.341	0.189	0
48006	Newmarket	Eagle St. W./McCaffrey Rd.	55	0.100	0.100	0.229	0.318	0.424	0.693	0.100	0.250	0.146	0
51001	Ottawa Downtown	Rideau St./Wurtemburg St.	49	0.100	0.209	0.264	0.399	0.542	1.017	0.100	0.323	0.205	0

2019 toluene annual statistics

Unit: micrograms per cubic metre (μg/m³)
Toluene 24h AAQC (based on odour): 2,000 μg/m³

ID	City	Location	Number of samples	10%	25%	50%	75%	90%	Max	Min	Mean	Standard deviation
12016	Windsor West	College Ave./South St.	54	0.304	0.415	0.648	0.998	1.489	2.184	0.223	0.797	0.487
14111	Sarnia	700 Christina St.	57	0.100	0.243	0.542	0.931	1.638	6.652	0.100	0.779	0.996
15026	London	42 St. Julien St.	54	0.100	0.245	0.412	0.695	0.891	1.747	0.100	0.491	0.340
26060	Kitchener	West Ave./Homewood Ave.	57	0.100	0.307	0.433	0.618	1.019	4.530	0.100	0.572	0.626
29000	Hamilton Downtown	Elgin St./Kelly St.	59	0.279	0.361	0.624	1.031	1.581	3.573	0.100	0.817	0.676
34021	Toronto North	4905 Dufferin St., ECCC	50	0.487	0.677	1.065	1.586	2.780	6.942	0.100	1.390	1.183
48006	Newmarket	Eagle St. W./McCaffrey Rd.	55	0.100	0.100	0.252	0.476	0.779	2.731	0.100	0.418	0.471
51001	Ottawa Downtown	Rideau St./Wurtemburg St.	49	0.274	0.369	0.550	0.798	1.047	1.571	0.100	0.618	0.337

2019 ethylbenzene annual statistics

Unit: micrograms per cubic metre (μg/m³)
Ethylbenzene 24h AAQC: 1,000 μg/m³

ID	City	Location	Number of sample	10%	25%	50%	75%	90%	Max	Min	Mean	Standard deviation
12016	Windsor West	College Ave./South St.	54	0.040	0.050	0.121	0.174	0.222	0.589	0.040	0.137	0.106
14111	Sarnia	700 Christina St.	57	0.040	0.040	0.086	0.140	0.259	0.647	0.040	0.118	0.122
15026	London	42 St. Julien St.	54	0.040	0.040	0.040	0.094	0.117	0.251	0.040	0.070	0.049
26060	Kitchener	West Ave./Homewood Ave.	57	0.040	0.040	0.040	0.102	0.156	0.238	0.040	0.079	0.053
29000	Hamilton Downtown	Elgin St./Kelly St.	59	0.040	0.040	0.096	0.162	0.284	0.557	0.040	0.126	0.113
34021	Toronto North	4905 Dufferin St., ECCC	50	0.040	0.084	0.110	0.209	0.302	0.717	0.040	0.157	0.131
48006	Newmarket	Eagle St. W./McCaffrey Rd.	55	0.040	0.040	0.040	0.065	0.113	0.368	0.040	0.067	0.062
51001	Ottawa Downtown	Rideau St./Wurtemburg St.	49	0.040	0.040	0.040	0.083	0.139	0.202	0.040	0.064	0.043

2019 m- and p-xylene annual statistics

Unit: micrograms per cubic metre (μg/m³)

ID	City	Location	Number of sample	10%	25%	50%	75%	90%	Max	Min	Mean	Standard deviation
12016	Windsor West	College Ave./South St.	54	0.100	0.100	0.305	0.494	0.785	2.302	0.100	0.409	0.386
14111	Sarnia	700 Christina St.	57	0.100	0.100	0.202	0.300	0.533	1.114	0.100	0.256	0.224
15026	London	42 St. Julien St.	54	0.100	0.100	0.100	0.243	0.368	0.832	0.100	0.200	0.170
26060	Kitchener	West Ave./Homewood Ave.	57	0.100	0.100	0.100	0.273	0.431	0.775	0.100	0.223	0.174
29000	Hamilton Downtown	Elgin St./Kelly St.	59	0.100	0.100	0.247	0.529	0.883	1.841	0.100	0.398	0.406
34021	Toronto North	4905 Dufferin St., ECCC	50	0.100	0.229	0.317	0.651	1.012	2.098	0.100	0.500	0.446
48006	Newmarket	Eagle St. W./McCaffrey Rd.	55	0.100	0.100	0.100	0.218	0.376	1.068	0.100	0.191	0.198
51001	Ottawa Downtown	Rideau St./Wurtemburg St.	49	0.100	0.100	0.100	0.244	0.362	0.676	0.100	0.186	0.132

2019 o-xylene annual statistics

Unit: micrograms per cubic metre (μg/m³)

ID	City	Location	Number of sample	10%	25%	50%	75%	90%	Max	Min	Mean	Standard deviation
12016	Windsor West	College Ave./South St.	54	0.045	0.045	0.115	0.191	0.272	0.564	0.045	0.147	0.118
14111	Sarnia	700 Christina St.	57	0.045	0.045	0.045	0.119	0.200	0.414	0.045	0.101	0.085
15026	London	42 St. Julien St.	54	0.045	0.045	0.045	0.085	0.145	0.304	0.045	0.074	0.057
26060	Kitchener	West Ave./Homewood Ave.	57	0.045	0.045	0.045	0.101	0.147	0.302	0.045	0.083	0.061
29000	Hamilton Downtown	Elgin St./Kelly St.	59	0.045	0.045	0.101	0.187	0.310	0.814	0.045	0.145	0.149
34021	Toronto North	4905 Dufferin St., ECCC	50	0.045	0.045	0.109	0.197	0.320	0.680	0.045	0.156	0.143
48006	Newmarket	Eagle St. W./McCaffrey Rd.	55	0.045	0.045	0.045	0.045	0.127	0.315	0.045	0.068	0.057
51001	Ottawa Downtown	Rideau St./Wurtemburg St.	49	0.045	0.045	0.045	0.106	0.141	0.279	0.045	0.078	0.052

2019 1,3-butadiene annual statistics

Unit: micrograms per cubic metre (μg/m³)
1,3-Butadiene 24h AAQC: 10.0 μg/m³
1,3-butadiene annual AAQC: 2.0 μg/m³

ID	City	Location	Number of sample	10%	25%	50%	75%	90%	Max	Min	Mean	Standard deviation
12016	Windsor West	College Ave./South St.	54	0.025	0.025	0.025	0.025	0.025	0.090	0.025	0.028	0.013
14111	Sarnia	700 Christina St.	57	0.025	0.025	0.025	0.025	0.084	0.608	0.025	0.054	0.093
15026	London	42 St. Julien St.	54	0.025	0.025	0.025	0.025	0.025	0.025	0.025	0.025	0.000
26060	Kitchener	West Ave./Homewood Ave.	57	0.025	0.025	0.025	0.025	0.025	0.025	0.025	0.025	0.000
29000	Hamilton Downtown	Elgin St./Kelly St.	59	0.025	0.025	0.025	0.025	0.025	0.062	0.025	0.028	0.009
34021	Toronto North	4905 Dufferin St., ECCC	50	0.025	0.025	0.025	0.025	0.025	0.054	0.025	0.026	0.004
48006	Newmarket	Eagle St. W./McCaffrey Rd.	55	0.025	0.025	0.025	0.025	0.025	0.025	0.025	0.025	0.000
51001	Ottawa Downtown	Rideau St./Wurtemburg St.	49	0.025	0.025	0.025	0.025	0.025	0.079	0.025	0.027	0.010

10-year trends

10-year trend for nitric oxide (NO)

Annual mean (ppb)

ID	City/Town	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019	Change over 10 year (%)	Trend
12008	Windsor Downtown	4.7	4.5	4.7	3.7	4.0	3.5	3.1	3.3	3.2	2.7	-23.9	SSS
12016	Windsor West	6.1	3.8	4.6	3.6	3.8	4.2	2.9	2.6	2.6	3.1	-23.2	SSS
13001	Chatham	2.6	1.9	1.8	1.6	1.5	1.7	1.4	1.9	1.8	1.4	-12.0	SSS
14111	Sarnia	2.2	3.1	2.1	1.7	1.9	2.4	INS	1.5	1.8	1.7	-18.7	SSS
15020	Grand Bend	N/A	0.3	0.3	1.0	0.2	0.3	0.5	0.3	0.2	0.3	-9.3	Non-SSS
15026	London	2.9	3.3	4.2	1.4	1.3	1.4	1.0	1.0	0.8	0.9	-62.5	SSS
21005	Brantford	1.3	1.2	1.1	1.2	0.9	1.3	0.8	0.8	1.0	0.9	-8.7	Non-SSS
26060	Kitchener	2.5	2.0	2.1	1.6	1.6	1.6	1.3	1.0	0.9	1.2	-19.3	SSS
27067	St. Catharines	2.8	2.3	2.5	2.2	1.7	2.1	1.5	1.2	0.9	1.2	-44.9	SSS
28028	Guelph	2.0	2.3	2.2	1.1	1.2	1.3	1.1	1.1	1.2	0.9	-47.6	SSS
29000	Hamilton Downtown	5.0	4.8	4.6	4.3	3.9	1.3	4.2	3.9	3.9	4.0	-9.6	Non-SSS
29118	Hamilton West	N/A	6.4	6.3	5.4	5.9	5.1	6.2	3.9	4.2	4.2	-24.2	SSS
29214	Hamilton Mountain	2.2	2.3	1.9	2.0	2.0	1.8	1.2	1.2	1.2	1.8	-32.0	SSS
33003	Toronto East	7.8	7.6	6.6	5.7	6.2	5.8	5.4	4.4	3.1	3.4	-45.2	SSS
34021	Toronto North	5.7	6.2	5.0	4.1	4.3	3.9	3.5	3.0	2.5	2.7	-50.3	SSS
35125	Toronto West	13.4	12.4	11.3	8.6	9.5	9.2	8.2	7.7	6.7	7.5	-33.0	SSS
44008	Burlington	5.0	4.6	4.6	4.6	4.6	3.9	3.9	3.4	2.7	3.0	-35.9	SSS
44017	Oakville	3.6	2.7	3.4	2.1	3.4	2.7	1.8	1.7	1.8	1.8	-31.2	SSS
45027	Oshawa	2.3	2.3	2.1	1.5	2.0	2.3	2.5	2.4	0.9	0.9	-23.5	SSS
46090	Brampton	3.7	4.6	4.4	4.6	4.0	3.8	3.4	2.2	2.2	2.2	-45.8	SSS
46108	Mississauga	4.1	4.1	3.8	3.1	2.9	3.1	3.6	2.0	1.6	2.6	-33.5	SSS
47045	Barrie	4.3	3.8	3.2	3.2	3.7	3.5	3.7	2.6	1.8	2.2	-32.4	SSS
48006	Newmarket	2.3	2.2	2.0	1.5	1.4	1.7	1.6	1.4	1.3	1.3	-28.4	SSS
49005	Parry Sound	N/A	0.9	0.5	0.5	0.6	0.8	0.6	0.5	0.5	0.7	-1.6	Non-SSS
51001	Ottawa Downtown	1.6	1.8	2.4	2.1	1.9	2.0	1.7	1.5	1.7	1.6	-3.8	Non-SSS
52023	Kingston	0.3	0.5	0.4	0.2	0.8	0.9	0.7	0.6	0.6	0.6	44.4	SSS
54012	Belleville	2.3	2.3	1.6	1.7	1.2	1.5	1.8	1.1	1.0	1.3	-34.6	SSS
56051	Cornwall	2.0	1.9	2.2	1.9	1.5	1.8	2.1	1.2	1.4	1.5	-7.3	Non-SSS
59006	Peterborough	1.7	2.2	1.8	1.7	1.8	1.5	1.3	1.2	0.9	1.2	-47.7	SSS
63203	Thunder Bay	4.6	5.9	5.1	4.7	4.2	5.2	3.8	4.1	3.8	3.8	-22.7	SSS
71078	Sault Ste. Marie	1.9	2.0	1.7	1.3	2.0	1.7	1.0	1.3	1.2	1.5	-35.2	SSS
75010	North Bay	3.4	4.0	2.9	2.5	2.6	2.1	2.0	1.6	1.7	1.8	-53.4	SSS

Notes:

N/A indicates data not available.
INS indicates there was insufficient data to calculate a valid annual mean.
Station 14111 replaced station 14064 as the Sarnia site in 2016.
Station 15026 replaced station 15025 as the London site in 2013.
Station 29214 replaced station 29114 as the Hamilton Mountain site in 2019.
Station 34021 replaced station 34020 as the Toronto North site in 2017.
Station 45027 replaced station 45026 as the Oshawa site in 2018.
Station 46090 replaced station 46089 as the Brampton site in 2017.
Station 52023 replaced station 52022 as the Kingston site in 2014.
SSS - Significant Sen's Slope (significant trend detected).
N-SSS - Non-Significant Sen's Slope (significant trend not detected).

10-year trend for nitrogen dioxide (NO₂)

Annual mean (ppb)

ID	City/Town	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019	Change over 10 year (%)	Trend
12008	Windsor Downtown	15.6	14.5	13.2	12.4	14.0	12.7	11.4	11.1	11.0	10.9	-24.2	SSS
12016	Windsor West	14.5	12.9	11.4	11.5	11.8	11.4	10.6	9.9	8.8	10.0	-28.5	SSS
13001	Chatham	6.4	6.6	5.7	6.0	6.8	6.8	5.4	6.1	5.1	5.8	-12.0	Non-SSS
14111	Sarnia	8.0	8.6	8.6	8.1	9.0	9.3	INS	7.3	7.6	6.8	-16.8	SSS
15020	Grand Bend	N/A	3.6	3.6	4.4	3.1	3.4	2.8	3.0	3.3	2.5	-24.2	SSS
15026	London	8.8	8.3	6.3	6.4	6.9	6.6	5.4	5.8	5.4	5.8	-25.6	SSS
21005	Brantford	5.8	6.1	5.4	4.8	5.5	5.5	4.8	4.4	5.2	5.6	-7.0	SSS
26060	Kitchener	7.7	7.7	7.1	6.7	7.0	6.8	6.2	5.8	5.8	6.3	-19.7	SSS
27067	St. Catharines	9.1	8.5	8.1	7.7	7.3	7.3	6.6	6.6	6.0	6.0	-31.7	SSS
28028	Guelph	6.7	7.3	6.5	6.6	7.1	6.3	6.2	5.9	5.9	5.4	-19.3	SSS
29000	Hamilton Downtown	12.7	13.5	11.9	12.4	12.4	12.2	11.9	11.9	11.6	12.5	-5.8	Non-SSS
29118	Hamilton West	N/A	13.1	12.1	12.7	12.8	12.2	11.8	10.4	11.0	11.3	-12.9	SSS
29214	Hamilton Mountain	8.9	9.9	8.6	9.0	9.3	9.0	7.9	7.8	7.8	8.8	-12.9	SSS
33003	Toronto East	14.8	15.2	14.0	13.6	14.2	13.9	12.1	11.5	10.6	10.2	-32.8	SSS
34021	Toronto North	14.3	15.4	13.4	12.9	13.4	12.9	12.0	10.5	10.4	10.5	-32.4	SSS
35125	Toronto West	20.1	19.1	16.3	16.1	17.1	16.6	15.7	15.0	14.4	14.6	-25.3	SSS
44008	Burlington	12.2	11.8	11.0	11.0	10.9	10.4	10.2	9.7	9.4	9.6	-19.7	SSS
44017	Oakville	9.2	10.3	9.1	9.2	8.2	7.5	8.2	8.2	8.5	9.1	-14.3	SSS
45027	Oshawa	7.2	7.0	5.6	5.9	6.8	6.6	6.3	6.4	3.8	3.5	-33.9	SSS
46090	Brampton	10.7	11.3	10.4	9.1	10.6	9.9	9.7	8.3	8.1	8.6	-26.4	SSS
46108	Mississauga	10.4	10.6	9.6	9.5	9.2	9.2	8.6	8.0	7.2	8.4	-25.1	SSS
47045	Barrie	8.7	8.6	8.1	7.8	8.1	7.4	8.1	7.3	6.4	6.3	-23.1	SSS
48006	Newmarket	7.2	8.1	7.2	6.8	6.8	6.8	6.5	6.3	6.1	5.5	-23.7	SSS
49005	Parry Sound	N/A	3.6	3.3	2.9	3.3	3.2	2.9	2.7	2.9	2.6	-24.4	SSS
51001	Ottawa Downtown	7.4	7.9	7.8	7.9	7.4	7.4	6.9	7.1	7.3	6.7	-14.2	SSS
52023	Kingston	4.3	4.6	4.0	3.6	3.9	4.4	4.4	4.4	4.2	4.0	-9.0	SSS
54012	Belleville	5.5	6.3	4.7	4.7	4.5	4.8	5.1	4.3	3.7	4.2	-22.7	SSS
56051	Cornwall	6.5	6.5	6.1	6.2	5.6	5.3	5.5	5.0	5.1	5.0	-20.9	SSS
59006	Peterborough	5.0	4.3	3.7	5.0	5.3	5.1	4.5	4.7	4.5	3.9	-18.9	SSS
63203	Thunder Bay	7.8	8.6	7.3	7.3	7.8	7.5	7.1	6.7	7.5	6.7	-15.3	SSS
71078	Sault Ste. Marie	5.5	5.3	4.8	5.0	5.3	4.8	4.0	4.4	4.4	4.5	-22.3	SSS
75010	North Bay	7.6	7.4	6.1	5.8	5.6	5.6	4.7	4.6	4.9	5.1	-34.7	SSS

Notes:

N/A indicates data not available.
INS indicates there was insufficient data to calculate a valid annual mean.
Station 14111 replaced station 14064 as the Sarnia site in 2016.
Station 15026 replaced station 15025 as the London site in 2013.
Station 29214 replaced station 29114 as the Hamilton Mountain site in 2019.
Station 34021 replaced station 34020 as the Toronto North site in 2017.
Station 45027 replaced station 45026 as the Oshawa site in 2018.
Station 46090 replaced station 46089 as the Brampton site in 2017.
Station 52023 replaced station 52022 as the Kingston site in 2014.
SSS - Significant Sen's Slope (significant trend detected).
N-SSS - Non-Significant Sen's Slope (significant trend not detected).

10-year trend for nitrogen oxides (NO_x)

Annual mean (ppb)

ID	City/Town	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019	Change over 10 year (%)	Trend
12008	Windsor Downtown	20.2	18.9	17.8	16.2	18.0	16.2	14.5	14.4	14.2	13.6	-24.6	SSS
12016	Windsor West	20.6	16.7	16.0	15.2	15.7	15.5	13.5	12.5	11.3	13.0	-27.4	SSS
13001	Chatham	9.0	8.4	7.5	7.7	8.2	8.5	6.8	8.0	6.9	7.2	-14.8	SSS
14111	Sarnia	10.2	11.7	10.7	9.8	10.9	11.7	INS	8.7	9.4	8.5	-19.5	SSS
15020	Grand Bend	N/A	4.0	3.9	5.4	3.4	3.8	3.3	3.4	3.4	2.7	-24.0	SSS
15026	London	11.7	11.6	10.5	7.8	8.3	8.0	6.5	6.8	6.2	6.6	-40.8	SSS
21005	Brantford	7.2	7.3	6.7	5.7	6.4	6.8	5.7	5.3	6.2	6.5	-6.3	SSS
26060	Kitchener	10.3	9.6	9.2	8.3	8.5	8.4	7.5	6.9	6.7	7.4	-20.9	SSS
27067	St. Catharines	11.8	10.9	10.6	9.9	9.1	9.4	8.2	7.9	6.8	7.1	-34.7	SSS
28028	Guleph	8.6	9.5	8.8	7.8	8.4	7.7	7.3	7.0	7.1	6.4	-25.6	SSS
29118	Hamilton West	N/A	19.5	18.4	18.1	18.7	17.3	17.9	14.2	15.2	16.5	-6.1	SSS
29214	Hamilton Mountain	11.2	12.2	10.5	11.0	11.3	10.9	9.2	9.1	8.9	15.4	-18.7	SSS
31103	Toronto Downtown	20.3	18.4	16.2	16.1	16.5	16.1	15.9	15.7	14.0	10.7	-15.8	SSS
33003	Toronto East	22.6	22.8	20.6	19.4	20.4	19.7	17.5	15.8	13.7	13.7	-38.3	SSS
34021	Toronto North	20.0	21.5	18.5	17.0	17.7	16.9	15.4	13.5	12.8	13.2	-39.7	SSS
35125	Toronto West	33.5	31.5	27.6	24.7	26.5	25.7	23.8	22.7	21.1	22.1	-28.9	SSS
44008	Burlington	17.2	16.4	15.6	15.6	15.5	14.3	14.2	13.2	12.0	12.6	-23.8	SSS
44017	Oakville	12.8	13.0	12.6	11.2	11.6	10.1	10.1	9.9	10.4	10.9	-20.4	SSS
45027	Oshawa	9.5	9.2	7.8	7.4	8.8	8.9	8.8	8.8	4.7	4.4	-30.5	SSS
46090	Brampton	14.4	15.9	14.8	13.9	14.6	13.7	13.1	10.6	10.3	10.74	-34.6	SSS
46108	Mississauga	14.5	14.7	13.4	12.6	12.1	12.3	12.2	9.9	8.8	10.97	-29.1	SSS
47045	Barrie	13.1	12.4	11.3	11.0	11.8	10.9	11.9	9.9	8.3	8.52	-26.8	SSS
48006	Newmarket	9.5	10.3	9.2	8.4	8.2	8.5	8.1	7.8	7.4	6.78	-23.8	SSS
49005	Parry Sound	N/A	4.5	3.8	3.4	4.0	4.0	3.6	3.3	3.3	3.34	-20.5	SSS
51001	Ottawa Downtown	9.0	9.7	10.2	10.1	9.3	9.5	8.6	8.6	9.0	8.31	-13.1	SSS
52023	Kingston	4.7	5.3	4.6	3.8	4.8	5.3	5.2	4.9	4.7	4.55	-9.4	SSS
54012	Belleville	7.8	8.7	6.4	6.3	5.7	6.2	6.7	5.4	4.7	5.53	-28.5	SSS
56051	Cornwall	8.5	8.4	8.4	8.0	7.0	7.1	7.6	6.2	6.3	6.54	-19.6	SSS
59006	Peterborough	6.7	6.6	5.4	6.6	7.1	6.6	5.9	5.8	5.3	5.14	-26.0	SSS
63203	Thunder Bay	12.4	14.5	12.4	12.0	11.9	12.7	11	10.8	11.3	10.44	-18.5	SSS
71078	Sault Ste. Marie	7.4	7.2	6.4	6.3	7.3	6.6	5.1	5.8	5.6	5.95	-24.8	SSS
75010	North Bay	11.0	11.5	9.1	8.3	8.1	7.8	6.7	6.2	6.6	6.91	-39.3	SSS

Notes:

N/A indicates data not available.
INS indicates there was insufficient data to calculate a valid annual mean.
Station 14111 replaced station 14064 as the Sarnia site in 2016.
Station 15026 replaced station 15025 as the London site in 2013.
Station 29214 replaced station 29114 as the Hamilton Mountain site in 2019.
Station 34021 replaced station 34020 as the Toronto North site in 2017.
Station 45027 replaced station 45026 as the Oshawa site in 2018.
Station 46090 replaced station 46089 as the Brampton site in 2017.
Station 52023 replaced station 52022 as the Kingston site in 2014.
SSS - Significant Sen's Slope (significant trend detected).
N-SSS - Non-Significant Sen's Slope (significant trend not detected).

10-year trend for fine particulate matter (PM_2.5)

Annual mean (µg/m³)

ID	City/Town	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019	Change over 10 year (%)	Trend
12008	Windsor Downtown	9.4	9.4	9.8	9.2	10.1	9.3	8.1	7.8	8.5	7.8	-20.8	SSS
12016	Windsor West	9.6	9.7	9.5	10.0	10.7	9.9	8.5	8.5	8.7	9.1	-12.3	SSS
13001	Chatham	8.1	8.2	7.5	8.1	8.6	8.1	6.6	6.4	6.8	6.8	-20.0	SSS
14111	Sarnia	12.7	12.9	12.7	8.5	9.0	8.4	INS	7.0	7.4	7.1	-46.1	SSS
15020	Grand Bend	7.8	7.6	7.4	7.3	8.1	7.7	6.0	5.1	5.6	5.4	-41.5	SSS
15026	London	7.8	7.7	8.1	9.1	8.8	8.3	7.1	7.0	7.3	6.7	-22.1	SSS
16015	Port Stanley	7.4	7.5	7.4	7.4	8.2	8.0	6.5	6.3	6.8	6.7	-16.5	SSS
18007	Tiverton	5.7	6.0	6.0	5.8	6.5	6.4	5.1	5.1	5.7	5.0	-18.2	SSS
21005	Brantford	8.0	8.2	7.8	8.5	9.2	8.7	7.3	7.2	7.7	7.4	-13.0	SSS
26060	Kitchener	7.8	7.7	7.7	8.7	9.3	8.8	7.3	7.0	7.4	7.2	-13.5	SSS
27067	St. Catharines	8.0	7.8	7.9	8.5	8.8	8.4	6.9	7.0	7.0	7.0	-18.2	SSS
28028	Guelph	7.0	7.4	7.4	8.1	8.9	8.4	6.9	6.8	7.4	7.1	-9.2	N-SSS
29000	Hamilton Downtown	9.4	10.0	10.2	10.1	10.8	10.2	8.2	8.5	9.2	8.8	-18.0	SSS
29118	Hamilton West	8.3	8.8	9.0	9.6	9.9	9.9	7.9	7.5	8.2	7.8	-18.8	SSS
29214	Hamilton Mountain	7.6	8.3	8.1	9.2	9.4	9.0	7.2	7.4	7.7	7.9	-16.1	SSS
33003	Toronto East	8.3	7.8	7.8	8.2	8.9	8.5	7.0	7.4	7.2	7.0	-14.7	SSS
34021	Toronto North	7.7	9.5	9.0	8.3	9.2	9.4	7.3	7.4	7.6	6.8	-26.1	SSS
35125	Toronto West	8.1	8.7	8.8	8.8	9.1	8.5	7.0	7.4	7.7	7.2	-22.6	SSS
44008	Burlington	7.7	7.8	8.0	8.7	9.6	9.4	7.6	7.0	7.2	7.0	-19.8	SSS
44017	Oakville	7.0	8.0	7.6	8.0	8.5	8.3	7.0	6.9	7.4	7.2	-11.5	SSS
45027	Oshawa	7.0	6.9	6.9	7.4	7.7	7.5	5.9	5.9	6.4	6.1	-18.9	SSS
46090	Brampton	7.2	7.6	7.2	8.5	8.9	8.4	6.8	7.0	7.3	6.8	-10.5	N-SSS
46108	Mississauga	7.6	7.7	7.5	7.9	8.7	8.5	7.2	6.8	7.3	7.0	-13.6	SSS
47045	Barrie	6.8	7.2	7.1	7.5	7.6	7.6	6.5	7.0	7.7	7.5	2.5	N-SSS
48006	Newmarket	6.8	6.9	7.1	7.3	7.3	7.1	6.0	5.9	6.4	5.9	-21.2	SSS
49005	Parry Sound	5.5	6.0	6.0	5.8	5.8	5.7	4.8	4.6	5.0	4.4	-32.8	SSS
49010	Dorset	5.1	5.4	5.3	5.4	5.3	5.6	4.6	4.6	4.9	4.1	-17.6	SSS
51001	Ottawa Downtown	5.7	6.3	6.2	7.0	7.0	6.9	5.9	5.9	5.9	5.9	-8.6	N-SSS
51010	Petawawa	4.2	4.5	4.8	4.8	4.7	4.8	4.4	4.1	3.6	3.8	-19.2	SSS
52023	Kingston	8.0	8.5	8.3	6.5	6.8	6.3	5.8	5.3	5.6	5.4	-38.3	SSS
54012	Belleville	5.6	6.2	6.5	6.9	6.8	6.6	5.5	5.8	6.4	6.1	-3.7	N-SSS
56051	Cornwall	7.0	7.3	6.9	7.7	7.0	6.9	6.4	5.9	6.3	5.9	-21.7	SSS
59006	Peterborough	6.3	7.0	6.3	7.4	6.9	6.8	5.8	5.8	6.3	6.0	-16.7	SSS
63203	Thunder Bay	5.4	6.2	5.4	6.3	6.6	6.5	4.9	5.1	6.0	5.1	-11.4	SSS
71078	Sault Ste. Marie	5.2	5.7	5.6	5.6	6.0	5.9	4.9	5.0	5.5	4.8	-8.7	SSS
75010	North Bay	4.9	5.5	5.3	5.2	5.3	5.3	4.6	4.6	5.5	4.5	-14.8	SSS
77233	Sudbury	4.7	5.2	5.1	5.7	6.0	6.3	5.4	5.0	5.4	5.0	3.5	N-SSS

Notes:

From 2010-2012, measurements were taken by TEOM sampler operated at 30°C with a Sample Equilibration System (SES).
As of 2013, measurements taken by Synchronized Hybrid Ambient Real-time Particulate (SHARP) 5030.
An approximate correction factor was applied to the TEOM data prior to 2013 to be comparable to SHARP measurements and generate an approximate 10-year trend.
INS indicates there was insufficient data in any one quarter to calculate a valid annual mean.
Station 14111 replaced station 14064 as the Sarnia site in 2016.
Station 15026 replaced station 15025 as the London site in 2013.
Station 29214 replaced station 29114 as the Hamilton Mountain site in 2019.
Station 34021 replaced station 34020 as the Toronto North site in 2017.
Station 45027 replaced station 45026 as the Oshawa site in 2018.
Station 46090 replaced station 46089 as the Brampton site in 2017.
Station 52023 replaced station 52022 as the Kingston site in 2014.
SSS - Significant Sen's Slope (significant trend detected).
N-SSS - Non-Significant Sen's Slope (significant trend not detected).

10-year trend for ground-level ozone (O₃)

Annual mean (ppb)

ID	City/Town	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019	Change over 10 year (%)	Trend
12008	Windsor Downtown	28.0	27.2	28.0	26.9	26.0	27.0	27.7	27.3	26.9	26.6	-1.3	Non-SSS
12016	Windsor West	26.7	26.4	28.0	26.7	27.2	26.5	27.7	27.0	27.0	27.3	4.0	Non-SSS
13001	Chatham	31.9	29.7	29.5	29.6	29.3	29.6	29.6	29.5	28.7	29.2	-5.6	SSS
14111	Sarnia	30.7	29.7	29.7	28.6	27.1	27.8	28.8	28.4	29.0	29.2	-3.2	Non-SSS
15020	Grand Bend	35.0	32.8	33.2	32.3	31.0	30.4	30.7	31.0	31.5	31.6	-6.7	SSS
15026	London	28.2	26.8	27.7	28.7	28.1	27.9	28.2	28.1	27.6	26.8	0.7	Non-SSS
16015	Port Stanley	34.6	32.8	33.1	33.9	32.3	32.8	32.9	33.0	32.3	32.3	-3.8	SSS
18007	Tiverton	33.8	32.1	32.0	32.4	31.8	32.5	33.1	32.4	32.3	31.1	-2.2	Non-SSS
21005	Brantford	29.4	28.7	28.8	29.0	29.4	28.9	29.5	28.3	28.3	27.5	-5.0	SSS
26060	Kitchener	29.4	27.6	28.0	28.0	27.3	27.9	28.8	28.1	27.7	27.2	-2.3	Non-SSS
27067	St. Catharines	28.3	28.0	28.7	28.6	28.5	28.6	29.8	28.1	28.5	28.4	2.3	Non-SSS
28028	Guelph	30.7	28.9	28.8	29.0	27.8	27.7	28.7	28.4	28.9	26.3	-6.1	SSS
29000	Hamilton Downtown	26.9	25.4	25.7	25.0	25.3	25.9	26.7	25.6	25.6	24.4	-3.5	Non-SSS
29118	Hamilton West	24.5	24.2	24.2	24.4	22.7	23.9	24.4	25.0	25.5	23.6	1.0	Non-SSS
29214	Hamilton Mountain	29.7	28.8	30.2	29.5	29.1	29.4	29.5	29.1	29.3	27.5	-3.4	Non-SSS
33003	Toronto East	23.0	23.3	24.6	24.1	23.4	23.5	25.5	24.4	25.2	24.6	8.7	SSS
34021	Toronto North	24.8	23.6	25.7	25.3	25.3	25.7	25.9	24.0	25.5	24.1	1.0	Non-SSS
35125	Toronto West	20.6	20.1	21.5	21.5	21.1	21.3	22.1	22.1	22.3	21.8	10.1	SSS
44008	Burlington	26.6	25.9	26.7	26.4	25.5	26.5	27.6	27.1	27.6	26.6	5.6	SSS
44017	Oakville	28.0	26.8	27.7	28.3	27.2	27.4	27.1	27.4	28.7	27.1	0.8	Non-SSS
45027	Oshawa	28.0	26.6	27.0	27.2	27.2	26.2	27.2	27.9	25.8	24.4	-6.1	SSS
46090	Brampton	27.5	26.1	26.6	26.7	26.5	26.5	27.1	27.2	28.6	26.5	3.6	Non-SSS
46108	Mississauga	25.9	24.1	25.6	25.2	25.4	25.4	26.0	26.2	26.1	24.5	2.2	Non-SSS
47045	Barrie	26.8	25.3	26.3	25.5	25.6	25.4	25.9	25.9	27.5	25.7	1.1	Non-SSS
48006	Newmarket	31.5	27.8	29.4	28.7	28.6	28.5	28.6	27.9	29.8	27.8	-2.4	Non-SSS
49005	Parry Sound	31.3	29.7	30.1	30.4	29.6	30.4	29.6	29.7	30.8	29.8	-1.1	Non-SSS
49010	Dorset	28.6	27.0	28.0	28.1	27.7	27.0	27.4	26.9	28.2	27.5	-1.9	Non-SSS
51001	Ottawa Downtown	25.7	24.2	26.0	25.6	24.8	25.6	25.6	25.5	26.4	25.9	3.9	Non-SSS
51010	Petawawa	27.9	26.7	27.7	27.6	26.8	26.7	26.4	25.8	27.3	27.3	-2.1	Non-SSS
52023	Kingston	32.6	30.3	32.7	30.3	31.4	30.3	30.5	30.4	30.5	29.9	-4.1	SSS
54012	Belleville	30.0	27.9	28.0	29.2	29.6	29.6	30.5	30.2	29.9	29.6	6.0	SSS
56051	Cornwall	27.9	26.1	27.1	26.9	27.3	27.9	27.1	27.2	27.6	26.9	0.3	Non-SSS
59006	Peterborough	30.5	27.9	29.1	28.6	29.2	29.3	29.7	28.9	29.7	28.3	-0.4	Non-SSS
63203	Thunder Bay	25.7	25.2	25.0	26.3	23.4	24.0	23.2	23.4	24.3	23.7	-8.8	SSS
71078	Sault Ste. Marie	28.4	27.8	28.8	28.9	28.4	27.8	27.3	28.1	29.7	28.1	-0.7	Non-SSS
75010	North Bay	28.0	26.7	26.1	27.4	26.7	27.0	26.4	26.4	26.0	26.4	-4.2	SSS
77233	Sudbury	28.7	28.7	28.5	27.2	26.3	25.7	25.1	25.9	27.1	26.3	-10.7	SSS

Notes:

Station 14111 replaced station 14064 as the Sarnia site in 2016.
Station 15026 replaced station 15025 as the London site in 2013.
Station 29214 replaced station 29114 as the Hamilton Mountain site in 2019.
Station 34021 replaced station 34020 as the Toronto North site in 2017.
Station 46090 replaced station 46089 as the Brampton site in 2017.
Station 52023 replaced station 52022 as the Kingston site in 2014.
SSS - Significant Sen's Slope (significant trend detected).
N-SSS - Non-Significant Sen's Slope (significant trend not detected).

10-year trend for ground-level ozone (O₃) summer means (May - September)

Summer mean (ppb)

ID	City/Town	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019	Change over 10 year (%)	Trend
12008	Windsor Downtown	34.6	33.8	36.8	32.5	30.9	33.3	33.4	32.8	33.7	31.4	-8.2	Non-SSS
12016	Windsor West	31.8	31.9	35.7	30.9	30.9	31.8	33.0	31.8	32.4	31.2	-0.2	Non-SSS
13001	Chatham	36.5	34.4	36.6	34.2	32.4	34.4	32.9	33.1	32.1	31.9	-12.1	SSS
14111	Sarnia	34.3	32.9	36.6	32.0	29.4	31.1	32.1	32.0	34.0	31.5	-4.5	Non-SSS
15020	Grand Bend	37.8	33.9	38.9	33.1	31.5	32.3	32.0	32.1	32.7	31.7	-9.4	SSS
15026	London	32.5	30.7	34.4	30.9	29.5	31.0	30.4	29.8	30.5	27.4	-11.2	SSS
16015	Port Stanley	38.9	35.5	38.4	36.9	33.7	35.6	35.2	35.0	35.3	33.7	-12.4	SSS
18007	Tiverton	33.3	31.7	36.0	32.5	30.8	33.3	34.1	32.2	32.9	29.7	-5.8	Non-SSS
21005	Brantford	31.6	31.1	33.5	30.1	29.9	31.2	32.2	29.4	30.4	28.3	-9.4	Non-SSS
26060	Kitchener	31.6	30.2	33.5	29.8	28.5	30.2	31.8	29.8	30.6	29.2	-6.2	Non-SSS
27067	St. Catharines	32.0	31.2	35.0	31.2	29.5	31.7	33.2	29.8	31.3	29.7	-7.3	Non-SSS
28028	Guelph	32.5	31.3	34.5	30.4	28.9	30.2	31.2	29.6	31.7	27.3	-12.3	Non-SSS
29000	Hamilton Downtown	31.6	28.7	32.4	28.4	27.5	29.5	30.6	27.8	29.7	26.1	-13.2	Non-SSS
29118	Hamilton West	27.9	26.2	29.2	26.4	22.7	26.5	27.1	26.8	28.5	24.4	-4.2	Non-SSS
29214	Hamilton Mountain	34.4	32.3	37.4	32.5	31.6	33.9	33.2	31.5	34.0	29.6	-8.9	Non-SSS
33003	Toronto East	26.7	27.4	30.6	27.1	25.9	27.7	29.7	26.0	29.2	26.0	-3.0	Non-SSS
34021	Toronto North	28.0	27.5	32.7	29.4	28.6	30.7	30.7	26.3	30.4	25.9	-6.0	Non-SSS
35125	Toronto West	24.3	23.6	27.5	24.4	23.5	25.0	25.9	24.3	26.3	24.3	3.9	Non-SSS
44008	Burlington	30.2	29.2	32.5	29.2	27.4	30.1	30.5	29.0	31.8	28.8	-1.7	Non-SSS
44017	Oakville	31.5	29.9	34.2	30.6	28.3	30.2	29.9	29.5	32.4	28.8	-9.0	Non-SSS
45027	Oshawa	29.5	28.5	31.1	28.3	27.9	28.9	29.4	28.6	26.6	24.4	-11.7	SSS
46090	Brampton	30.8	29.3	32.7	29.5	28.9	30.3	31.2	29.5	32.7	28.2	-2.6	Non-SSS
46108	Mississauga	29.0	26.7	30.4	26.5	26.5	28.0	28.5	27.2	28.3	24.9	-4.3	Non-SSS
47045	Barrie	27.9	26.2	29.7	25.6	25.4	26.8	27.4	25.6	29.0	24.7	-4.7	Non-SSS
48006	Newmarket	34.4	30.5	34.2	30.3	29.4	31.2	31.7	29.0	33.2	28.4	-7.4	Non-SSS
49005	Parry Sound	30.4	28.7	32.8	30.1	28.2	31.4	28.9	27.7	30.9	27.8	-4.8	Non-SSS
49010	Dorset	25.2	23.8	28.3	25.3	24.4	24.6	25.1	23.0	25.8	23.9	-4.0	Non-SSS
51001	Ottawa Downtown	26.1	25.1	29.3	26.5	24.6	27.8	27.5	25.3	27.6	25.6	1.2	Non-SSS
51010	Petawawa	23.8	22.8	28.1	24.5	22.9	24.4	23.4	21.1	23.7	22.9	-5.3	Non-SSS
52023	Kingston	35.9	32.0	38.5	32.4	32.7	32.2	33.3	30.9	33.1	30.0	-10.8	Non-SSS
54012	Belleville	34.2	29.9	32.7	30.6	30.4	33.2	33.7	30.9	32.4	30.0	-2.8	Non-SSS
56051	Cornwall	29.8	26.7	30.7	28.1	27.0	29.7	28.7	27.1	29.4	26.1	-5.7	Non-SSS
59006	Peterborough	32.0	29.8	34.2	29.5	30.0	31.5	32.3	29.2	32.2	28.1	-5.3	Non-SSS
63203	Thunder Bay	23.9	24.2	25.3	24.7	22.7	23.6	22.0	20.4	22.1	21.8	-15.5	SSS
71078	Sault Ste. Marie	27.2	26.4	30.3	28.2	27.4	28.1	26.3	26.3	29.1	26.2	-2.2	Non-SSS
75010	North Bay	28.4	26.3	28.5	26.9	26.2	27.8	26.4	24.7	26.3	25.7	-8.4	SSS
77233	Sudbury	26.3	26.9	29.8	28.0	27.0	27.7	26.6	25.8	28.8	25.9	-4.4	Non-SSS

Notes:

Station 14111 replaced station 14064 as the Sarnia site in 2016.
Station 15026 replaced station 15025 as the London site in 2013.
Station 29214 replaced station 29114 as the Hamilton Mountain site in 2019.
Station 34021 replaced station 34020 as the Toronto North site in 2017.
Station 46090 replaced station 46089 as the Brampton site in 2017.
Station 52023 replaced station 52022 as the Kingston site in 2014.
SSS - Significant Sen's Slope (significant trend detected).
N-SSS - Non-Significant Sen's Slope (significant trend not detected).

10-year trend for ground-level ozone (O₃) winter means (January-April, October-December)

Winter mean (ppb)

ID	City/Town	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019	Change over 10 year (%)	Trend
12008	Windsor Downtown	23.2	22.5	21.7	22.8	22.8	22.4	23.6	23.3	22.4	23.1	1.4	Non-SSS
12016	Windsor West	22.8	22.5	22.3	23.4	24.5	22.7	23.9	23.6	23.1	24.4	5.5	Non-SSS
13001	Chatham	28.5	26.7	24.3	26.2	27.1	26.3	27.2	26.8	26.2	27.4	0.3	Non-SSS
14111	Sarnia	28.1	27.4	24.7	26.2	25.4	25.4	INS	26.0	25.4	27.6	-1.9	Non-SSS
15020	Grand Bend	33.0	32.1	29.1	31.8	30.6	29.1	29.8	30.2	30.7	31.6	-3.9	Non-SSS
15026	London	25.0	24.2	22.9	26.9	27.1	25.8	26.6	26.9	25.6	26.4	6.4	Non-SSS
16015	Port Stanley	31.5	31.0	29.3	31.8	31.3	31.2	31.2	31.5	30.2	31.4	-0.5	Non-SSS
18007	Tiverton	34.1	32.2	29.2	32.4	32.7	31.9	32.4	32.6	31.9	32.1	-1.1	Non-SSS
21005	Brantford	27.8	27.1	25.4	28.3	28.8	27.2	27.7	27.5	26.7	26.9	-2.3	Non-SSS
26060	Kitchener	27.8	25.7	24.0	26.7	26.5	26.1	26.6	27.1	25.6	25.8	-2.7	Non-SSS
27067	St. Catharines	25.6	25.8	24.1	26.8	27.9	26.3	27.2	27.0	26.4	27.5	6.4	SSS
28028	Guelph	29.3	27.2	24.8	28.0	27.0	26.0	26.8	27.5	26.9	25.7	-5.6	Non-SSS
29000	Hamilton Downtown	23.5	23.1	20.9	22.5	23.7	23.3	23.9	24.2	22.6	23.2	2.6	Non-SSS
29118	Hamilton West	22.1	22.7	20.6	23.0	22.8	22.1	22.5	23.7	23.3	23.0	5.0	SSS
29214	Hamilton Mountain	26.3	26.3	25.0	27.3	27.3	26.3	26.8	27.4	25.9	25.9	1.0	Non-SSS
33003	Toronto East	20.4	20.4	20.3	22.0	21.6	20.5	22.5	23.3	22.4	23.5	13.8	SSS
34021	Toronto North	22.5	20.8	20.7	22.3	22.8	22.1	22.6	22.3	22.0	22.8	3.0	Non-SSS
35125	Toronto West	18.0	17.7	17.2	19.5	19.4	18.6	19.4	20.5	19.4	20.1	11.4	SSS
44008	Burlington	23.9	23.5	22.5	24.4	24.1	23.8	25.6	25.7	24.7	25.2	6.8	SSS
44017	Oakville	25.5	24.7	23.1	26.6	26.5	25.3	25.1	25.9	26.0	26.0	2.6	Non-SSS
45027	Oshawa	26.9	25.2	24.1	26.4	26.7	24.3	25.6	27.3	25.4	24.5	-3.0	Non-SSS
46090	Brampton	25.2	23.8	22.2	24.6	24.8	23.8	24.1	25.6	25.6	25.3	6.8	Non-SSS
46108	Mississauga	23.7	22.5	22.2	24.3	24.7	23.6	24.2	25.5	24.6	24.2	7.5	Non-SSS
47045	Barrie	26.0	24.7	23.9	25.5	25.8	24.4	24.8	26.3	26.5	26.4	5.6	Non-SSS
48006	Newmarket	29.4	25.8	26.0	27.5	28.1	26.6	26.3	27.2	27.3	27.3	2.6	Non-SSS
49005	Parry Sound	31.9	30.4	28.1	30.6	30.6	29.8	30.0	31.1	30.7	31.3	2.2	Non-SSS
49010	Dorset	31.0	29.5	27.7	30.1	30.1	28.8	29.0	29.6	30.0	30.1	0.7	Non-SSS
51001	Ottawa Downtown	25.5	23.6	23.5	24.9	25.1	24.0	24.3	25.6	25.5	26.2	6.8	SSS
51010	Petawawa	30.8	29.5	27.5	29.9	29.6	28.5	28.6	29.3	29.8	30.4	1.4	Non-SSS
52023	Kingston	30.0	29.0	28.6	28.8	30.4	28.9	28.5	30.2	28.6	29.9	-0.3	Non-SSS
54012	Belleville	27.0	26.4	24.6	28.2	29.1	27.0	28.2	29.7	28.1	29.3	10.6	Non-SSS
56051	Cornwall	26.5	25.7	24.2	25.7	27.6	26.6	26.0	27.4	26.3	27.5	3.9	Non-SSS
59006	Peterborough	29.5	26.6	25.5	28.0	28.6	27.7	27.8	28.7	27.9	28.5	1.9	Non-SSS
63203	Thunder Bay	27.1	26.1	24.7	27.4	23.8	24.2	24.2	25.6	25.9	25.1	-4.8	Non-SSS
71078	Sault Ste. Marie	29.3	28.9	27.6	29.4	29.2	27.7	28.0	29.5	30.2	29.5	2.6	Non-SSS
75010	North Bay	27.7	27.0	24.4	27.8	27.1	26.4	26.4	27.6	25.9	26.9	-3.0	Non-SSS
77233	Sudbury	30.5	30.0	27.6	26.6	25.8	24.3	24.0	26.1	26.0	26.7	-16.7	SSS

Notes:

Station 14111 replaced station 14064 as the Sarnia site in 2016.
Station 15026 replaced station 15025 as the London site in 2013.
Station 29214 replaced station 29114 as the Hamilton Mountain site in 2019.
Station 34021 replaced station 34020 as the Toronto North site in 2017.
Station 46090 replaced station 46089 as the Brampton site in 2017.
Station 52023 replaced station 52022 as the Kingston site in 2014.
SSS - Significant Sen's Slope (significant trend detected).
N-SSS - Non-Significant Sen's Slope (significant trend not detected).

10-year trend for sulphur dioxide (SO₂)

Annual mean (ppb)
SO₂ 1y AAQC: 4 ppb

ID	City/Town	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019	Change over 10 year (%)	Trend
12008	Windsor Downtown	3.5	3.5	2.8	2.4	2.4	1.9	1.1	1.0	0.6	0.4	-97.1	SSS
12016	Windsor West	3.2	3.4	2.8	2.6	2.8	1.9	1.4	0.9	0.7	0.8	-89.8	SSS
14111	Sarnia	3.9	5.3	4.1	3.8	3.5	3.2	INS	1.7	1.9	1.9	-76.3	SSS
29000	Hamilton Downtown	3.3	5.2	4.8	4.8	5.1	4.3	3.2	3.5	5.0	4.8	-12.8	Non-SSS
29214	Hamilton Mountain	2.9	4.1	3.7	2.8	2.9	2.6	1.8	1.8	2.4	3.5	-45.5	SSS
35125	Toronto West	0.9	1.5	0.6	0.6	0.7	1.0	0.6	0.5	0.3	0.3	-76.7	SSS
51001	Ottawa Downtown	0.2	0.4	0.3	0.3	0.3	0.4	0	0.1	0.2	0.2	-26.8	Non-SSS
71078	Sault Ste. Marie	0.7	0.8	0.6	0.8	0.8	0.8	0.6	0.7	0.8	0.7	-12.2	Non-SSS
77233	Sudbury	1.3	1.5	1.3	2.8	2.4	2.4	2.1	1.3	1.2	1.2	-29.9	SSS

Notes:

INS indicates there was insufficient data to calculate a valid annual mean.
Station 14111 replaced station 14064 as the Sarnia site in 2016.
Station 29214 replaced station 29114 as the Hamilton Mountain site in 2019.
Station 77233 replaced station 77219 as the Sudbury site in 2013.
SSS - Significant Sen's Slope (significant trend detected).
N-SSS - Non-Significant Sen's Slope (significant trend not detected).

10-year trend for carbon monoxide (CO)

1h maximum (ppm)
CO 1h AAQC: 30 ppm

ID	City/Town	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019	Change over 10 year (%)	Trend
12008	Windsor Downtown	2.5	3.8	2.1	1.9	1.8	1.9	2.3	2.6	1.9	2.3	-7.3	N-SSS
29000	Hamilton Downtown	2.2	1.8	1.7	2.0	2.9	1.3	1.4	2.1	1.7	1.9	-6.3	N-SSS
35125	Toronto West	1.8	1.4	1.4	1.4	1.6	1.3	1.7	1.2	0.9	1.5	-15.8	N-SSS
51001	Ottawa Downtown	1.5	1.5	0.9	0.9	0.8	0.8	0.9	0.7	1.0	0.7	-38.0	SSS

Notes:

SSS - Significant Sen's Slope (significant trend detected).
N-SSS - Non-Significant Sen's Slope (significant trend not detected).

10-year trend for benzene

Annual mean (µg/m³)

ID	City/Town	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019	Change over 10 year (%)	Trend
12016	Windsor West	0.687	INS	0.558	0.519	0.610	0.566	0.521	0.450	0.478	0.445	-28.9	SSS
14111	Sarnia	0.961	INS	0.900	0.820	1.007	1.191	0.689	0.604	0.574	0.419	-42.3	SSS
15026	London	0.490	INS	0.455	0.413	0.446	0.451	0.341	0.339	0.321	0.296	-39.5	SSS
26060	Kitchener	0.537	INS	0.479	N/A	0.483	0.548	0.395	0.446	0.355	0.290	-41.6	SSS
29000	Hamilton Downtown	1.060	INS	0.977	INS	0.899	1.092	0.675	0.569	0.639	0.568	-35.1	SSS
48006	Newmarket	0.416	N/A	0.371	0.406	0.422	0.425	0.328	0.385	INS	0.250	-32.4	SSS
51001	Ottawa Downtown	0.451	0.418	0.422	0.442	0.413	0.453	0.365	0.388	0.405	0.323	-20.7	SSS

Notes:

INS indicates there was insufficient data to calculate a valid annual mean.
N/A indicates data not available.
The 2016 average for Sarnia is derived from data from May to December 2016.
Station 14111 replaced station 14064 as the Sarnia site in 2016.
The 2018 average for Windsor West is derived from data from February to July, and October to December in 2018.
The 2018 average for Sarnia is derived from data from February to May, July, and October to December in 2018.
The 2018 average for Hamilton Downtown is derived from data from March to June, August, and October to December in 2018.
SSS - Significant Sen's Slope (significant trend detected).

10-year trend for toluene

Annual mean (µg/m³)

ID	City/Town	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019	Change over 10 year (%)	Trend
12016	Windsor West	1.679	INS	1.392	1.017	1.542	1.248	1.272	0.972	1.131	0.797	-35.7	SSS
14111	Sarnia	2.037	INS	2.539	1.587	1.908	2.350	1.778	1.550	1.014	0.779	-41.1	SSS
15026	London	1.334	INS	1.408	0.887	0.839	1.013	0.727	0.633	0.657	0.491	-50.9	SSS
26060	Kitchener	1.477	INS	1.322	N/A	1.278	1.052	1.020	1.002	0.625	0.572	-47.7	SSS
29000	Hamilton Downtown	2.842	INS	2.067	INS	2.229	2.249	1.642	1.296	0.862	0.817	-47.2	SSS
48006	Newmarket	0.878	N/A	0.877	0.916	0.732	1.340	1.118	0.807	INS	0.418	-30.8	SSS
51001	Ottawa Downtown	1.212	0.929	0.899	0.975	0.741	0.982	0.902	0.826	0.704	0.618	-29.4	SSS

Notes:

INS indicates there was insufficient data to calculate a valid annual mean.
N/A indicates data not available.
The 2016 average for Sarnia is derived from data from May to December 2016.
Station 14111 replaced station 14064 as the Sarnia site in 2016.
The 2018 average for Windsor West is derived from data from February to July, and October to December in 2018.
The 2018 average for Sarnia is derived from data from February to May, July, and October to December in 2018.
The 2018 average for Hamilton Downtown is derived from data from March to June, August, and October to December in 2018.
SSS - Significant Sen's Slope (significant trend detected).

10-year trend for ethylbenzene

Annual mean (µg/m³)

ID	City/Town	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019	Change over 10 year (%)	Trend
12016	Windsor West	0.275	INS	0.221	0.179	0.267	0.238	0.234	0.181	0.187	0.137	-37.4	SSS
14111	Sarnia	0.392	INS	0.278	0.255	0.253	0.362	0.282	0.211	0.235	0.118	-36.6	SSS
15026	London	0.190	INS	0.143	0.125	0.121	0.149	0.108	0.105	0.141	0.070	-43.5	SSS
26060	Kitchener	0.220	INS	0.162	N/A	0.167	0.168	0.159	0.164	0.109	0.079	-37.9	SSS
29000	Hamilton Downtown	0.278	INS	0.193	INS	0.192	0.210	0.186	0.187	0.129	0.126	-28.7	SSS
48006	Newmarket	0.154	N/A	0.115	0.134	0.125	0.249	0.215	0.130	INS	0.067	-29.4	SSS
51001	Ottawa Downtown	0.144	0.122	0.105	0.112	0.099	0.123	0.119	0.120	0.088	0.064	-24.9	SSS

Notes:

INS indicates there was insufficient data to calculate a valid annual mean.
N/A indicates data not available.
The 2016 average for Sarnia is derived from data from May to December 2016.
Station 14111 replaced station 14064 as the Sarnia site in 2016.
The 2018 average for Windsor West is derived from data from February to July, and October to December in 2018.
The 2018 average for Sarnia is derived from data from February to May, July, and October to December in 2018.
The 2018 average for Hamilton Downtown is derived from data from March to June, August, and October to December in 2018.
SSS - Significant Sen's Slope (significant trend detected).
N-SSS - Non-Significant Sen's Slope (significant trend not detected).

10-year trend for m- and p-xylene

Annual mean (µg/m³)

ID	City/Town	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019	Change over 10 year (%)	Trend
12016	Windsor West	0.818	INS	0.689	0.536	0.825	0.702	0.635	0.505	0.502	0.409	-41.9	SSS
14111	Sarnia	0.790	INS	0.676	0.510	0.629	0.850	0.495	0.499	0.563	0.256	-32.3	SSS
15026	London	0.500	INS	0.388	0.345	0.318	0.398	0.267	0.268	0.407	0.200	-38.2	SSS
26060	Kitchener	0.639	INS	0.478	N/A	0.469	0.464	0.434	0.451	0.276	0.223	-39.1	SSS
29000	Hamilton Downtown	0.842	INS	0.603	INS	0.594	0.621	0.518	0.532	0.359	0.398	-30.2	SSS
48006	Newmarket	0.437	N/A	0.333	0.362	0.334	0.582	0.484	0.350	INS	0.191	-33.6	SSS
51001	Ottawa Downtown	0.429	0.355	0.310	0.329	0.309	0.363	0.338	0.334	0.222	0.186	-30.6	SSS

Notes:

INS indicates there was insufficient data to calculate a valid annual mean.
N/A indicates data not available.
The 2016 average for Sarnia is derived from data from May to December 2016.
Station 14111 replaced station 14064 as the Sarnia site in 2016.
The 2018 average for Windsor West is derived from data from February to July, and October to December in 2018.
The 2018 average for Sarnia is derived from data from February to May, July, and October to December in 2018.
The 2018 average for Hamilton Downtown is derived from data from March to June, August, and October to December in 2018.
SSS - Significant Sen's Slope (significant trend detected).
N-SSS - Non-Significant Sen's Slope (significant trend not detected).

10-year trend for o-xylene

Annual mean (µg/m³)

ID	City/Town	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019	Change over 10 year (%)	Trend
12016	Windsor West	0.255	INS	0.228	0.184	0.283	0.239	0.232	0.190	0.184	0.147	-32.2	SSS
14111	Sarnia	0.262	INS	0.244	0.171	0.226	0.313	0.178	0.192	0.213	0.101	-30.2	SSS
15026	London	0.147	INS	0.126	0.118	0.113	0.146	0.103	0.103	0.148	0.074	-31.8	SSS
26060	Kitchener	0.188	INS	0.157	N/A	0.166	0.164	0.153	0.164	0.107	0.082	-40.9	SSS
29000	Hamilton Downtown	0.241	INS	0.195	INS	0.206	0.216	0.189	0.198	0.131	0.145	-18.5	SSS
48006	Newmarket	0.133	N/A	0.116	0.126	0.134	0.218	0.192	0.128	INS	0.068	-24.8	N-SSS
51001	Ottawa Downtown	0.147	0.128	0.118	0.118	0.111	0.136	0.127	0.132	0.089	0.078	-18.5	SSS

Notes:

INS indicates there was insufficient data to calculate a valid annual mean.
N/A indicates data not available.
The 2016 average for Sarnia is derived from data from May to December 2016.
Station 14111 replaced station 14064 as the Sarnia site in 2016.
The 2018 average for Windsor West is derived from data from February to July, and October to December in 2018.
The 2018 average for Sarnia is derived from data from February to May, July, and October to December in 2018.
The 2018 average for Hamilton Downtown is derived from data from March to June, August, and October to December in 2018.
SSS - Significant Sen's Slope (significant trend detected).
N-SSS - Non-Significant Sen's Slope (significant trend not detected).

10-year trend for 1,3-butadiene

Annual mean (µg/m³)

ID	City/Town	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019	Change over 10 year (%)	Trend
12016	Windsor West	0.056	INS	0.048	0.036	0.042	0.035	0.032	0.034	0.028	0.028	-41.0	SSS
14111	Sarnia	0.167	INS	0.205	0.209	0.124	0.216	0.089	0.077	0.088	0.054	-46.8	SSS
15026	London	0.050	INS	0.040	0.023	0.025	0.026	0.020	0.035	0.025	0.025	-36.0	SSS
26060	Kitchener	0.056	INS	0.042	N/A	0.029	0.029	0.023	0.038	0.026	0.025	-35.1	SSS
29000	Hamilton Downtown	0.060	INS	0.046	INS	0.032	0.037	0.025	0.039	0.028	0.028	-31.5	SSS
48006	Newmarket	0.051	N/A	0.039	0.021	0.020	0.028	0.024	0.035	INS	0.025	-32.2	SSS
51001	Ottawa Downtown	0.052	0.041	0.040	0.035	0.026	0.030	0.027	0.037	0.032	0.027	-36.9	SSS

Notes:

INS indicates there was insufficient data to calculate a valid annual mean.
N/A indicates data not available.
The 2016 average for Sarnia is derived from data from May to December 2016.
Station 14111 replaced station 14064 as the Sarnia site in 2016.
The 2018 average for Windsor West is derived from data from February to July, and October to December in 2018.
The 2018 average for Sarnia is derived from data from February to May, July, and October to December in 2018.
The 2018 average for Hamilton Downtown is derived from data from March to June, August, and October to December in 2018.
SSS - Significant Sen's Slope (significant trend detected).

Canadian Ambient Air Quality Standard reporting

PM_2.5 and ozone CAAQS metric values for designated sites across Ontario (2019)

Air zone area	City/Town	24-hour PM_2.5 (μg/m³)	Annual PM_2.5 (μg/m³)	8-hour ozone (ppb)
Sarnia	Sarnia	19	7.2	71*(44)
Hamilton	Hamilton Downtown	22	8.8	62(44)
Hamilton	Hamilton Mountain	20	7.6	65*(48)
Sudbury	Sudbury	14	5.2	60(45)
Sault Ste. Marie	Sault Ste. Marie	13	5.1	57(46)
Northern Ontario	Thunder Bay	14	5.4	50(47)
Southern Ontario	Windsor Downtown	20	8.1	70*(42)
Southern Ontario	Chatham	17	6.7	64*(49)
Southern Ontario	London	18	7.2	65*(48)
Southern Ontario	Brantford	18	7.4	63(50)
Southern Ontario	Kitchener	19	7.2	63(50)
Southern Ontario	Guelph	19	7.1	63(49)
Southern Ontario	St. Catharines	17	7	62(47)
Southern Ontario	Burlington	18	7.1	66*(48)
Southern Ontario	Oakville	19	7.1	65*(48)
Southern Ontario	Milton	19	7.4	67*(51)
Southern Ontario	Mississauga	19	7.1	62(47)
Southern Ontario	Brampton	20	7.1	65*(50)
Southern Ontario	Toronto	19	7.7	65*(49)
Southern Ontario	Oshawa	17	6.1	63(48)
Southern Ontario	Barrie	20	7.4	58(47)
Southern Ontario	Peterborough	16	6.1	63(49)
Southern Ontario	Kingston	15	5.5	64*(50)
Southern Ontario	Ottawa Downtown	15	5.8	57(48)

Notes:

Designated sites normally refer to communities with populations greater than 100,000.
Toronto reporting is based on Toronto Downtown, Toronto North, Toronto East and Toronto West stations.
The CAAQS for 24h PM_2.5 is 28 µg/m³ based on the 98^th percentile measurement annually, averaged over three consecutive years.
The CAAQS for annual PM_2.5 is 10 µg/m³ based on the annual mean averaged over three consecutive years.
The CAAQS for ozone is 63 ppb based on the consecutive three-year average of the annual 4^th highest daily maximum eight-hour running average.
An asterisk indicates an exceedance of the CAAQS.
Value in parenthesis is the calculated 8h ozone CAAQS metric once the transboundary influence was removed.

PM_2.5 and ozone CAAQS metric trends for designated sites across Ontario (2010-2019)

Air zone area	City/Town	10-year trend (%) based on 24-hour PM_2.5	10-year trend (%) based on Annual PM_2.5	10-year trend (%) based on 8-hour ozone
Sarnia	Sarnia	-43.5	-51.4	-6.3*
Hamilton	Hamilton Downtown	-23.1	-7.4*	-7.8
Hamilton	Hamilton Mountain	-18	-6.2*	-8.5
Sudbury	Sudbury	-8.6	9.0*	-10.2
Sault Ste. Marie	Sault Ste. Marie	-24.1	-7.3*	-9.5
Northern Ontario	Thunder Bay	-18.8	-2.1*	-8.3
Southern Ontario	Windsor Downtown	-23.1	-15.6	-8.1
Southern Ontario	Chatham	31.3	-21.2	-12.3
Southern Ontario	London	-13	-11.3*	0*
Southern Ontario	Brantford	-23.5	-6.7*	-12.5
Southern Ontario	Kitchener	-15.7*	-6.9*	-4.4*
Southern Ontario	Guelph	-10.2*	-3.0*	-6.4*
Southern Ontario	St. Catharines	-26.1*	-12.4*	-8.1
Southern Ontario	Burlington	-18.8	-7.9*	-6.4
Southern Ontario	Oakville	-11.7	-3.4*	-8.5
Southern Ontario	Mississauga	-11.2*	-8.0*	-3.4*
Southern Ontario	Brampton	-5.6*	-3.3*	-4.9
Southern Ontario	Toronto	-27.7	-16	-8.7
Southern Ontario	Oshawa	-20.5	-14.1*	-8.6
Southern Ontario	Barrie	-6.8	4.2*	-10.1
Southern Ontario	Peterborough	-24.5	-11.2*	10.3
Southern Ontario	Kingston	-58.3	-40.7	-15.6
Southern Ontario	Ottawa Downtown	-13.5*	-6.1*	-7.4*

Notes:

Designated sites normally refer to communities with populations greater than 100,000.
Toronto reporting is based on Toronto Downtown, Toronto North, Toronto East and Toronto West stations.
*Non-Significant Sen’s Slope (significant trend not detected).

AQHI and Air Quality Alert Program Reporting

2019 Air Quality Health Index summary

Station ID	City/Town	No. of valid hours	Low risk AQHI=1	Low risk AQHI=2	Low risk AQHI=3	Moderate risk AQHI=4	Moderate risk AQHI=5	Moderate risk AQHI=6	High risk AQHI=7	High risk AQHI=8	No. of days at least 1 hour > 6
12008	Windsor Downtown	8444	1.85	42.12	44.56	10.23	1.20	0.02	0.01	0	1
12016	Windsor West	8613	2.23	41.65	43.75	10.84	1.45	0.08	0	0	0
13001	Chatham	8694	9.73	53.29	31.19	5.56	0.23	0	0	0	0
14111	Sarnia	8684	8.92	51.20	31.20	7.30	1.27	0.07	0.05	0	4
15020	Grand Bend	8449	16.63	60.58	19.82	2.64	0.25	0	0.08	0	3
15026	London	8735	14.59	56.34	25.80	3.10	0.17	0	0	0	0
16015	Port Stanley	8673	12.87	54.51	28.29	4.06	0.27	0	0	0	0
18007	Tiverton	8632	14.61	63.00	20.41	1.85	0.12	0	0.01	0	1
21005	Brantford	8708	13.78	53.67	28.16	4.13	0.16	0.06	0.03	0	2
26060	Kitchener	8711	11.24	55.17	29.71	3.35	0.32	0.20	0.01	0	1
27067	St. Catharines	8604	8.60	56.66	31.32	3.24	0.17	0	0	0	0
28028	Guelph	8722	15.08	57.74	23.91	3.00	0.23	0.05	0	0	0
29000	Hamilton Downtown	8585	2.83	38.25	44.34	11.87	2.48	0.22	0	0	0
29118	Hamilton West	8724	5.90	44.92	38.87	8.93	1.24	0.14	0	0	0
29214	Hamilton Mountain	8691	5.10	47.52	37.84	7.71	1.67	0.16	0	0	0
31103	Toronto Downtown	2880	0.56	29.90	49.72	14.38	4.90	0.56	0	0	0
31129	Toronto Downtown	4570	2.41	43.74	39.91	12.28	1.60	0.07	0	0	0
33003	Toronto East	8719	6.79	50.29	34.77	7.00	0.80	0.23	0.07	0.05	2
34021	Toronto North	8535	9.00	46.46	34.90	8.04	1.35	0.18	0.08	0	1
35125	Toronto West	8505	2.12	39.93	46.27	10.03	1.20	0.39	0.06	0.01	2
44008	Burlington	8666	4.66	48.20	39.51	6.70	0.82	0.10	0	0	0
44017	Oakville	8618	5.06	47.96	38.85	7.14	0.87	0.13	0	0	0
44029	Milton	8521	3.84	51.00	36.99	7.29	0.81	0.07	0	0	0
45027	Oshawa	8667	25.57	61.69	12.06	0.68	0	0	0	0	0
46090	Brampton	8657	7.95	51.05	33.88	6.04	0.89	0.18	0.01	0	1
46108	Mississauga	8667	9.59	56.13	29.20	4.67	0.33	0.07	0	0	0
47045	Barrie	8493	13.28	56.98	25.53	3.83	0.33	0.06	0	0	0
48006	Newmarket	8668	14.24	59.07	22.70	3.67	0.21	0.07	0.05	0	1
49005	Parry Sound	8605	19.54	65.23	13.88	1.30	0.06	0	0	0	0
49010	Dorset	8640	24.42	61.25	13.94	0.39	0	0	0	0	0
51001	Ottawa Downtown	8481	16.05	52.89	27.32	3.56	0.18	0	0	0	0
51010	Petawawa	8631	26.62	62.00	11.27	0.10	0	0	0	0	0
52023	Kingston	8726	12.81	63.73	21.49	1.94	0.03	0	0	0	0
54012	Belleville	8582	11.16	63.37	22.76	2.65	0.07	0	0	0	0
56051	Cornwall	8699	17.00	60.23	21.06	1.52	0.20	0	0	0	0
59006	Peterborough	8715	18.26	59.66	19.61	2.41	0.07	0	0	0	0
63203	Thunder Bay	8441	22.07	55.76	20.03	2.10	0.04	0	0	0	0
71078	Sault Ste. Marie	8623	19.18	57.85	21.38	1.52	0.07	0	0	0	0
75010	North Bay	8664	19.61	62.30	15.84	2.11	0.14	0	0	0	0
77233	Sudbury	8682	14.33	59.77	21.73	3.50	0.63	0.03	0	0	0
81103	Toronto Downtown	1185	1.27	42.53	45.57	10.63	0	0	0	0	0

2019 air quality alert summary

Air quality forecast region	Special air quality statement	Smog and air health advisory
Algonquin	0	0
Atikokan - Upsala - Quetico	1	0
Attawapiskat	1	0
Bancroft - Bon Echo Park	0	0
Barrie - Orillia - Midland	0	0
Belleville - Quinte - Northumberland	0	0
Big Trout Lake - Sachigo Lake	1	0
Brockville - Leeds and Grenville	0	0
Burk's Falls - Bayfield Inlet	0	0
Chapleau - Gogama	1	0
City of Hamilton	0	0
City of Ottawa	0	0
City of Thunder Bay	0	0
City of Toronto	1	0
Cornwall - Morrisburg	0	0
Dryden - Ignace	1	0
Dufferin - Innisfil	0	0
Dunnville - Caledonia - Haldimand	0	0
Elgin	0	0
Elliot Lake - Ranger Lake	0	0
Fort Frances - Rainy Lake	1	0
Fort Hope - Webequie	1	0
Fort Severn	1	0
Geraldton - Manitouwadge - Hornepayne	1	0
Greater Sudbury and Vicinity	0	0
Grey - Bruce	0	0
Haliburton	0	0
Halton - Peel	0	0
Huron - Perth	0	1
Kapuskasing - Hearst	1	0
Kenora - Nestor Falls	1	0
Kingston - Prince Edward	0	0
Kirkland Lake - New Liskeard - Temagami	0	0
Lake Nipigon - Wabakimi	1	0
London - Middlesex	0	0
Manitoulin - Northshore - Killarney	0	0
Moosonee - Fort Albany	1	0
Niagara	0	0
Nipigon - Marathon - Superior North	0	0
North Bay - West Nipissing	0	0
Oxford - Brant	0	0
Parry Sound - Muskoka	0	0
Peawanuck	1	0
Peterborough - Kawartha Lakes	0	0
Pickle Lake - Wunnummin Lake	2	0
Prescott and Russell	0	0
Red Lake - Ear Falls	2	0
Renfrew - Pembroke - Barry's Bay	0	0
Sandy Lake - Pikangikum	2	0
Sarnia - Lambton	1	0
Sault Ste. Marie - Superior East	0	0
Simcoe - Delhi - Norfolk	0	0
Sioux Lookout - Savant Lake	1	0
Smiths Falls - Lanark - Sharbot Lake	0	0
Stirling - Tweed - South Frontenac	0	0
Superior West	1	0
Timmins - Cochrane	1	0
Waterloo - Wellington	0	0
Wawa - White River - Pukaskwa	0	0
Windsor - Essex - Chatham - Kent	0	0
York - Durham	0	0
Ontario	4	1

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Updated: November 02, 2023

Published: August 18, 2021

Appendix

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Monitoring network operations

Network description

Quality assurance and quality control

Data base

Network descriptive table

Annual statistics and 10-year trends

Other informative tables

2019 air monitoring network

2019 Ontario continuous ambient air monitoring network

Notes:

2019 annual statistics

2019 nitric oxide (NO) annual statistics

2019 nitrogen dioxide (NO2) annual statistics

2019 nitrogen oxides (NOx) annual statistics

2019 fine particulate matter (PM2.5) annual statistics

Notes

2019 ground-level ozone (O3) annual statistics

2019 sulphur dioxide (SO2) annual statistics

2019 carbon monoxide (CO) annual statistics

2019 total reduced sulphur (TRS) compounds annual statistics

2019 benzene annual statistics

2019 toluene annual statistics

2019 ethylbenzene annual statistics

2019 m- and p-xylene annual statistics

2019 o-xylene annual statistics

2019 1,3-butadiene annual statistics

10-year trends

10-year trend for nitric oxide (NO)

Notes:

10-year trend for nitrogen dioxide (NO2)

Notes:

10-year trend for nitrogen oxides (NOx)

Notes:

10-year trend for fine particulate matter (PM2.5)

Notes:

10-year trend for ground-level ozone (O3)

Notes:

10-year trend for ground-level ozone (O3) summer means (May - September)

Notes:

10-year trend for ground-level ozone (O3) winter means (January-April, October-December)

Notes:

10-year trend for sulphur dioxide (SO2)

Notes:

10-year trend for carbon monoxide (CO)

Notes:

10-year trend for benzene

Notes:

10-year trend for toluene

Notes:

10-year trend for ethylbenzene

Notes:

10-year trend for m- and p-xylene

Notes:

10-year trend for o-xylene

Notes:

10-year trend for 1,3-butadiene

Notes:

Canadian Ambient Air Quality Standard reporting

PM2.5 and ozone CAAQS metric values for designated sites across Ontario (2019)

Notes:

PM2.5 and ozone CAAQS metric trends for designated sites across Ontario (2010-2019)

Notes:

AQHI and Air Quality Alert Program Reporting

2019 Air Quality Health Index summary

2019 air quality alert summary

References and resources

2019 nitrogen dioxide (NO₂) annual statistics

2019 nitrogen oxides (NO_x) annual statistics

2019 fine particulate matter (PM_2.5) annual statistics

2019 ground-level ozone (O₃) annual statistics

2019 sulphur dioxide (SO₂) annual statistics

10-year trend for nitrogen dioxide (NO₂)

10-year trend for nitrogen oxides (NO_x)

10-year trend for fine particulate matter (PM_2.5)

10-year trend for ground-level ozone (O₃)

10-year trend for ground-level ozone (O₃) summer means (May - September)

10-year trend for ground-level ozone (O₃) winter means (January-April, October-December)

10-year trend for sulphur dioxide (SO₂)

PM_2.5 and ozone CAAQS metric values for designated sites across Ontario (2019)

PM_2.5 and ozone CAAQS metric trends for designated sites across Ontario (2010-2019)