The Appendix is intended for use in conjunction with the 2020 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 2020, 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 2020 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. 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/NOx, PM2.5, 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 PM2.5, whereas for ozone, only the 2nd and 3rd 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 and/or monthly mean for 24-hour VOC samples require 50% of valid samples.

Network descriptive table

The AQHI network for 2020 is summarized in the 2020 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, PM2.5, ozone, SO2, CO and TRS compounds) based on the pollutant(s) of concern for the regional area it represents.

The 2020 Ontario Continuous Ambient Air Monitoring Network also identifies the type of air monitoring site: ambient, roadside, 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 trends

The annual statistical data and trends for various continuous pollutants and selected volatile organic compounds are presented in the Appendix. 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 70th percentile is 0.10 ppm).

The 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 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 PM2.5, ozone, NO2 and SO2 are presented for 2020 (based on a three-year average, 2018-2020) and over a 10-year period in Canadian Ambient Air Quality Standard Reporting. The air zone management levels associated to each CAAQS reporting pollutant is also provided for reference. 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 2020 are summarized in AQHI and Air Quality Alert Program Reporting. Traffic volumes and pollutant concentrations over the COVID‑19 pandemic period are presented as well.

2020 air monitoring network

2020 Ontario continuous ambient air monitoring network

IDStation nameStation locationYearLatitudeLongtiudeAir intakeTypeAQHINO2PM2.5O3SO2COTRS
12008Windsor Downtown467 University Ave. W.196942°18'58.8"-83°02'37.2"4A/RS/C/NYTTTTTN/A
12016Windsor WestCollege Ave./South St.197542°17'34.4"-83°04'23.3"4A/NYTTTTN/AT
13001Chatham435 Grand Ave. W.200542°24'13.3"-82°12'29.9"15A/C/NYTTTN/AN/AN/A
14111Sarnia700 Christina St. N.201642°59'25.0" -82°23'43.2"3A/C/NYTTTTN/AT
15020Grand BendPoint Blake Conservation Area199143°19'59.1"-81°44'34.4"5A/NYTTTN/AN/AN/A
15026London42 St. Julien St.201342°58'28.1"-81°12'03.1"5A/C/NYTTTN/AN/AN/A
16015Port Stanley43665 Dexter Line, Elgin Water T. Plant200242°40'19.5"-81°09'46.4"5A/NYTTTN/AN/AN/A
18007Tiverton4th Concession/Bruce Rd. 23197944°18'52.1"-81°32'59.0"4A/NYN/ATTN/AN/AN/A
21005Brantford324 Grand River Ave.200443°08'19.0"-80°17'33.5"5A/C/NYTTTN/AN/AN/A
26060KitchenerWest Ave./Homewood Ave. 199043°26'37.8"-80°30'13.7"5A/C/NYTTTN/AN/AN/A
27067St. CatharinesArgyle Cres., Pump Stn.198743°09'36.2"-79°14'05.1"4A/C/NYTTTN/AN/AN/A
28028GuelphExhibition St./Clark St. W. 200043°33'05.8"-80°15'51.0"4A/C/NYTTTN/AN/AN/A
29000Hamilton DowntownElgin St./Kelly St. 198743°15'28.0"-79°51'42.0"4A/RS/C/NYTTTTTT
29118Hamilton WestMain St. W./Hwy 403198543°15'26.8"-79°54'27.9"3A/RS/NYTTTN/AN/AN/A
29214Hamilton Mountain250 Fennell Ave. W.201943°14'28.4"-79°53'21.9"3A/C/NYTTTTN/AN/A
31129Toronto Downtown55 John St., Metro Hall201943°38'43.5"-79°23'20.7"2A/RS/C/NYTTTN/AN/AN/A
33003Toronto EastKennedy Rd./Lawrence Ave. E. 197043°44'52.5"-79°16'26.6"4A/RS/C/NYTTTN/AN/AN/A
34021Toronto North4905 Dufferin St., ECCC198843°46'53.8"-79°25'03.8"5A/RS/C/NYTTTTTN/A
35125Toronto West125 Resources Rd.200343°42'34.0"-79°32'36.6"8A/RS/C/NYTTTTTN/A
44008BurlingtonNorth Shore Blvd. E./Lakeshore Rd. 197943°18'54.4"-79°48'09.5"5A/C/NYTTTN/AN/AN/A
44017OakvilleEightLine/Glenashton Dr., Halton Reservoir200343°29'12.9"-79°42'08.2"12A/C/NYTTTN/AN/AN/A
44029Milton1120 Main St. E.201943°31'46.7"-79°51'44.8"4A/C/NYTTTTN/AN/A
45027OshawaBrittania Ave. W., Ep Taylor Stables200543°57'07.5"-78°54'45.2"7A/C/NYTTTN/AN/AN/A
46090Brampton109 Mclaughlin Rd. S.200043°41'55.5"-79°46'51.3"5A/C/NYTTTN/AN/AN/A
46108Mississauga3359 Mississauga Rd. N., U of T Campus200743°32'49.1"-79°39'31.3"5A/C/NYTTTN/AN/AN/A
47045Barrie83 Perry St.200144°22'56.5"-79°42'08.3"5A/C/NYTTTN/AN/AN/A
48006NewmarketEagle St. W./Mccaffrey Rd.200144°02'39.5"-79°28'59.7"5A/NYTTTN/AN/AN/A
49005Parry Sound7 Bay St.200145°20'16.3"-80°02'17.4"5A/NYTTTN/AN/AN/A
49010Dorset1026 Bellwood Acres Rd.198145°13'27.4"-78°55'58.6"3A/NYN/ATTN/AN/AN/A
51001Ottawa DowntownRideau St./Wurtemburg St.197145°26'03.6"-75°40'33.6"4A/C/NYTTTTTN/A
51010PetawawaPetawawa Research Forest Facility200745°59'48.2"-77°26'28.3"6A/NYN/ATTN/AN/AN/A
52023Kingston23 Beechgrove Lane201444°13'11.5"-76°31'16.1"5A/C/NYTTTN/AN/AN/A
54012Belleville2 Sidney St., Water Treatment Plant200244°09'01.9"-77°23'43.8"10A/NYTTTN/AN/AN/A
56051CornwallBedford St./3rd St. W.197045°01'04.7"-74°44'06.8"4A/NYTTTN/AN/AN/A
59006Peterborough10 Hospital Dr.199844°18'06.9"-78°20'46.4"10A/C/NYTTTN/AN/AN/A
63203Thunder Bay421 James St. S. 200448°22'45.8"-89°17'24.6"15A/RS/C/NYTTTN/AN/AN/A
71078Sault Ste. MarieSault College200446°31'59.5"-84°18'35.7"8A/C/NYTTTTN/AT
75010North BayChippewa St. W., Dept. National Defence197946°19'23.5"-79°26'57.4"4A/RS/NYTTTN/AN/AN/A
77233Sudbury155 Elm St.201346°29'31.0"-81°00'11.2"3A/C/NYTTTTN/AN/A
Total       393639391154

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
PM2.5
fine particulate matter
O3
ground-level ozone
SO2
sulphur dioxide
CO
carbon monoxide
TRS
total reduced sulphur
Y
yes

2020 annual statistics

2020 nitric oxide (NO) annual statistics

Unit: parts per billion (ppb)

IDCityLocationValid h10%30%50%70%90%99%MeanMax 1hMax 24h
12008Windsor Downtown467 University Ave. W.87010.00.30.61.23.519.01.70179.734.1
12016Windsor WestCollege Ave./South St.86330.10.20.51.03.323.21.70117.328.2
13001Chatham435 Grand Ave. W.87420.30.50.71.23.214.01.5138.112.3
14111Sarnia700 Christina St. N.86980.40.60.91.53.110.11.5864.89.3
15020Grand BendPoint Blake Conservation Area87070.20.30.30.40.72.10.4214.61.9
15026London42 St. Julien St.87200.00.10.30.51.28.40.6872.29.3
16015Port Stanley43665 Dexter Line, Elgin Water T. Plt86940.00.00.10.20.82.10.278.21.7
21005Brantford324 Grand River Ave.86840.10.20.30.51.49.40.7861.410.1
26060KitchenerWest Ave./Homewood Ave.86550.00.10.20.41.48.50.6655.96.9
27067St. CatharinesArgyle Cres., Pump Stn.87290.10.30.50.71.411.10.9159.611.4
28028GuelphExhibition St./Clark St. W.87190.00.10.20.41.211.20.7577.516.9
29000Hamilton DowntownElgin St./Kelly St.87590.20.61.02.06.830.02.89127.240.6
29118Hamilton WestMain St. W./Hwy 40386740.00.30.92.27.438.63.15133.637.7
29214Hamilton Mountain250 Fennell Ave. W.87210.20.30.50.93.014.11.3551.410.2
31129Toronto Downtown55 John St.86281.01.72.85.011.835.55.18113.623.0
33003Toronto EastKennedy Rd./Lawrence Ave. E.87130.00.20.71.74.828.82.31187.246.3
34021Toronto North4905 Dufferin St., ECCC86880.10.40.71.43.928.02.12138.428.2
35125Toronto West125 Resources Rd.86810.10.61.94.412.749.25.15139.340.1
44008BurlingtonNorth Shore Blvd. E./Lakeshore Rd.87710.20.71.11.94.621.92.2694.718.2
44017OakvilleEightLine/Glenashton Dr., Halton Res.87430.10.40.50.82.415.61.2558.714.8
44029Milton1120 Main St. E.85410.30.40.71.34.742.92.68141.040.4
45027OshawaBrittania Ave. W., EP Taylor Stables85080.00.20.30.61.610.90.8594.67.1
46090Brampton109 McLaughlin Rd. S.87190.00.00.20.42.425.51.3589.429.6
46108Mississauga3359 Mississauga Rd. N., U of T Campus87190.00.20.40.62.622.31.42124.834.6
47045Barrie83 Perry St.87140.10.20.40.82.220.31.36106.314.7
48006NewmarketEagle St. W./McCaffrey Rd.87240.00.10.20.41.313.30.7751.59.7
49005Parry Sound7 Bay St.87100.00.10.20.30.75.70.4442.26.0
51001Ottawa DowntownRideau St./Wurtemburg St.87700.30.50.71.12.413.71.4180.526.1
52023Kingston23 Beechgrove Lane87150.20.30.40.61.34.50.6640.96.1
54012Belleville2 Sidney St., Water Treatment Plant87440.30.30.40.72.517.51.3884.042.6
56051CornwallBedford St./3rd St. W.87180.10.20.30.51.623.41.22119.430.0
59006Peterborough10 Hospital Dr.83620.00.10.30.62.012.70.98118.816.0
63203Thunder Bay421 James St. S.87590.50.71.12.18.832.03.39156.524.9
71078Sault Ste. MarieSault College84970.10.61.01.43.112.71.5858.08.4
75010North BayChippewa St. W., Dept. National Defence87660.30.50.61.02.315.41.3878.913.6
77233Sudbury155 Elm St.86990.40.61.01.64.427.92.38100.925.4

2020 nitrogen dioxide (NO2) annual statistics

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

IDCityLocationValid h10%30%50%70%90%99%MeanMax 1hMax 24hNumber of times above 1h criteriaNumber of times above 24h criteria
12008Windsor Downtown467 University Ave. W.87013.35.17.110.217.331.08.9945.824.200
12016Windsor WestCollege Ave./South St.86332.64.26.29.416.529.78.1444.723.500
13001Chatham435 Grand Ave. W.87421.92.94.05.89.418.75.0531.016.000
14111Sarnia700 Christina St. N.86980.82.14.07.013.925.65.8938.521.800
15020Grand BendPoint Blake Conservation Area87070.41.01.72.84.79.92.2828.99.100
15026London42 St. Julien St.87201.22.43.65.28.618.34.5038.618.900
16015Port Stanley43665 Dexter Line, Elgin Water T. Plt86941.01.62.23.04.79.62.6318.27.800
21005Brantford324 Grand River Ave.86841.52.43.24.58.418.34.3036.519.800
26060KitchenerWest Ave./Homewood Ave.86551.32.33.65.49.722.64.8739.223.200
27067St. CatharinesArgyle Cres., Pump Stn.87292.02.94.05.710.124.05.3337.918.500
28028GuelphExhibition St./Clark St. W.87191.32.33.55.510.022.84.8838.425.000
29000Hamilton DowntownElgin St./Kelly St.87593.15.07.611.620.233.49.8746.735.500
29118Hamilton WestMain St. W./Hwy 40386742.94.97.311.319.331.99.4545.731.300
29214Hamilton Mountain250 Fennell Ave. W.87211.72.94.67.915.630.06.9147.523.200
31129Toronto Downtown55 John St.86284.77.510.514.522.239.112.3458.838.000
33003Toronto EastKennedy Rd./Lawrence Ave. E.87132.24.06.19.517.836.28.4163.932.200
34021Toronto North4905 Dufferin St., ECCC86882.64.46.710.118.734.48.8954.731.600
35125Toronto West125 Resources Rd.86813.46.69.814.624.140.612.1051.634.800
44008BurlingtonNorth Shore Blvd. E./Lakeshore Rd.87712.54.36.49.316.331.58.2146.025.200
44017OakvilleEightLine/Glenashton Dr., Halton Res.87432.03.24.87.314.130.36.7645.527.800
44029Milton1120 Main St. E.85412.13.55.28.116.633.27.5747.126.800
45027OshawaBrittania Ave. W., EP Taylor Stables85080.91.62.54.17.715.73.6129.515.800
46090Brampton109 McLaughlin Rd. S.87191.32.54.17.116.036.26.7551.035.800
46108Mississauga3359 Mississauga Rd. N., U of T Campus87191.93.24.87.513.627.86.6743.126.100
47045Barrie83 Perry St.87141.52.43.66.012.029.45.5847.124.800
48006NewmarketEagle St. W./McCaffrey Rd.87240.81.62.64.610.028.04.4942.323.500
49005Parry Sound7 Bay St.87100.51.01.52.45.015.12.3936.712.600
51001Ottawa DowntownRideau St./Wurtemburg St.87701.42.53.86.513.129.25.9249.626.800
52023Kingston23 Beechgrove Lane87151.01.62.33.47.120.23.4541.314.900
54012Belleville2 Sidney St., Water Treatment Plant87440.91.42.23.67.620.53.5336.417.300
56051CornwallBedford St./3rd St. W.87181.11.72.74.49.929.64.5951.926.600
59006Peterborough10 Hospital Dr.83620.81.52.54.29.024.54.0549.225.300
63203Thunder Bay421 James St. S.87591.22.33.96.614.032.86.1155.326.700
71078Sault Ste. MarieSault College84971.01.62.53.87.817.73.6736.915.100
75010North BayChippewa St. W., Dept. National Defence87660.91.52.44.19.229.44.2644.924.000
77233Sudbury155 Elm St.86991.52.53.76.114.037.86.2855.825.900

2020 nitrogen oxides (NOx) annual statistics

Unit: parts per billion (ppb)

IDCityLocationValid h10%30%50%70%90%99%MeanMax 1hMax 24h
12008Windsor Downtown467 University Ave. W.87013.75.78.011.520.047.910.7212.354.7
12016Windsor WestCollege Ave./South St.86332.94.87.010.619.248.39.9154.051.7
13001Chatham435 Grand Ave. W.87422.43.55.07.312.128.86.660.621.8
14111Sarnia700 Christina St. N.86981.53.05.18.616.931.57.591.626.1
15020Grand BendPoint Blake Conservation Area87070.61.32.13.25.411.62.737.710.1
15026London42 St. Julien St.87201.52.64.05.79.724.45.2105.528.2
16015Port Stanley43665 Dexter Line, Elgin Water T. Plt86941.11.72.33.35.410.92.923.98.9
21005Brantford324 Grand River Ave.86841.82.73.65.19.924.85.192.429.9
26060KitchenerWest Ave./Homewood Ave.86551.52.63.96.010.929.55.584.928.4
27067St. CatharinesArgyle Cres., Pump Stn.87292.43.34.56.311.432.26.290.428.4
28028GuelphExhibition St./Clark St. W.87191.52.53.85.911.033.15.697.034.0
29000Hamilton DowntownElgin St./Kelly St.87593.75.88.714.026.158.712.8161.164.8
29118Hamilton WestMain St. W./Hwy 40386743.15.48.714.125.964.712.6159.859.6
29214Hamilton Mountain250 Fennell Ave. W.87212.13.45.29.018.241.58.385.732.5
31129Toronto Downtown55 John St.86286.29.813.619.632.870.317.5157.760.1
33003Toronto EastKennedy Rd./Lawrence Ave. E.87132.44.77.211.221.459.110.7251.178.5
34021Toronto North4905 Dufferin St., ECCC86883.15.27.811.422.057.311.0162.755.9
35125Toronto West125 Resources Rd.86813.88.112.418.935.583.017.2173.173.4
44008BurlingtonNorth Shore Blvd. E./Lakeshore Rd.87713.15.17.711.220.550.410.5126.341.7
44017OakvilleEightLine/Glenashton Dr., Halton Res.87432.43.75.48.216.242.98.088.541.0
44029Milton1120 Main St. E.85412.64.26.29.621.270.510.3183.661.4
45027OshawaBrittania Ave. W., EP Taylor Stables85081.12.03.04.79.222.44.5109.620.8
46090Brampton109 McLaughlin Rd. S.87191.42.64.47.81859.58.09134.265.3
46108Mississauga3359 Mississauga Rd. N., U of T Campus87192.13.65.28.11646.48.02145.054.5
47045Barrie83 Perry St.87141.82.94.26.71446.56.94139.335.3
48006NewmarketEagle St. W./McCaffrey Rd.87240.91.82.951139.55.2278.133.1
49005Parry Sound7 Bay St.87100.61.11.72.75.918.72.8266.418.6
51001Ottawa DowntownRideau St./Wurtemburg St.87701.93.14.77.71541.07.33128.747.0
52023Kingston23 Beechgrove Lane87151.31.92.748.224.14.1273.019.8
54012Belleville2 Sidney St., Water Treatment Plant87441.21.92.84.51037.04.91106.056.5
56051CornwallBedford St./3rd St. W.87181.323.15.11248.45.81171.355.1
59006Peterborough10 Hospital Dr.83620.91.82.94.91135.05.02167.941.2
63203Thunder Bay421 James St. S.87591.93.35.39.22356.89.51211.848.4
71078Sault Ste. MarieSault College84971.62.43.55.41128.65.2490.319.4
75010North BayChippewa St. W., Dept. National Defence87661.32.13.25.31241.25.63120.937.6
77233Sudbury155 Elm St.86992.13.34.87.81862.48.66156.750.7

2020 fine particulate matter (PM2.5) annual statistics

Unit: micrograms per cubic metre (μg/m3)
PM2.5 24h AAQC: 27 μg/m3
PM2.5 Annual AAQC: 8.8 μg/m3

IDCityLocationValid h10%30%50%70%90%99%MeanMax 1hMax 24hNumber of times above 24h AAQCNumber of times above 1 year AAQC
12008Windsor Downtown467 University Ave. W.8722246813237.1422910
12016Windsor WestCollege Ave./South St.83752581116278.8683230
13001Chatham435 Grand Ave. W.8699235813256.7392200
14111Sarnia700 Christina St. N.8757236915267.1742300
15020Grand BendPoint Blake Conservation Area8619224610174.8241500
15026London42 St. Julien St.8693245813226.5492810
16015Port Stanley43665 Dexter Line, Elgin Water T. Plt8586235813246.5492200
18007Tiverton4th Concession/Bruce Rd. 238442224610174.8301600
21005Brantford324 Grand River Ave.8690246813236.7502600
26060KitchenerWest Ave./Homewood Ave.8753235813246.6442910
27067St. CatharinesArgyle Cres., Pump Stn.8685245812226.3442200
28028GuelphExhibition St./Clark St. W.8702135915276.9563120
29000Hamilton DowntownElgin St./Kelly St.87482471016298.1513310
29118Hamilton WestMain St. W./Hwy 4038626247915287.8503110
29214Hamilton Mountain250 Fennell Ave. W.8743246914257.1472600
31129Toronto Downtown55 John St.8627356914277.6472920
33003Toronto EastKennedy Rd./Lawrence Ave. E.8721135814266.7512700
34021Toronto North4905 Dufferin St., ECCC8689135813266.4522710
35125Toronto West125 Resources Rd.8675246813246.9532810
44008BurlingtonNorth Shore Blvd. E./Lakeshore Rd.8762235813236.4462500
44017OakvilleEightLine/Glenashton Dr., Halton Res.8672245712236.3472500
44029Milton1120 Main St. E.8504246814277.1483210
45027OshawaBrittania Ave. W., EP Taylor Stables8700245712226.2432100
46090Brampton109 McLaughlin Rd. S.8749245813256.7652500
46108Mississauga3359 Mississauga Rd. N., U of T Campus8748135814256.6442910
47045Barrie83 Perry St.8363235814276.8452910
48006NewmarketEagle St. W./McCaffrey Rd.8747235712225.9472600
49005Parry Sound7 Bay St.8673123610194.4291800
49010Dorset1026 Bellwood Acres Rd.862212359174.5391600
51001Ottawa DowntownRideau St./Wurtemburg St.8726235712246.0412710
51010PetawawaPetawawa Research Forest Facility855612358134.2221200
52023Kingston23 Beechgrove Lane8587234711215.6321700
54012Belleville2 Sidney St., Water Treatment Plant8578235813236.3342200
56051CornwallBedford St./3rd St. W.8731245711226.0422400
59006Peterborough10 Hospital Dr.8386124713235.6481900
63203Thunder Bay421 James St. S.8697234610205.5481500
71078Sault Ste. MarieSault College874922359164.5431700
75010North BayChippewa St. W., Dept. National Defence874412459174.6341800
77233Sudbury155 Elm St.8730234610205.1412000

Notes

  • Measurements taken by SHARP 5030.
  • The PM2.5 AAQC values, based on the 24-hour PM2.5 Canadian Ambient Air Quality Standard (CAAQS), are used "as is" for comparison to an average concentration in a year.

2020 ground-level ozone (O3) annual statistics

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

IDCityLocationValid h10%30%50%70%90%99%MeanMax 1hMax 24hNumber of times above 1h criterion
12008Windsor Downtown467 University Ave. W.870512212732436427.381531
12016Windsor WestCollege Ave./South St.864411202631416126.083492
13001Chatham435 Grand Ave. W.874415232834436129.177560
14111Sarnia700 Christina St. N.871913212632396226.782491
15020Grand BendPoint Blake Conservation Area870917253136436530.9935512
15026London42 St. Julien St.864811222834426027.777500
16015Port Stanley43665 Dexter Line, Elgin Water T. Plt866917253136446130.976530
18007Tiverton4th Concession/Bruce Rd. 23851018263135415830.575520
21005Brantford324 Grand River Ave.871612222834436028.074490
26060KitchenerWest Ave./Homewood Ave.869714222833405727.774460
27067St. CatharinesArgyle Cres., Pump Stn.873015253036456030.275540
28028GuelphExhibition St./Clark St. W.871113222732415927.070490
29000Hamilton DowntownElgin St./Kelly St.875211202632415826.377520
29118Hamilton WestMain St. W./Hwy 40386898192631415825.276500
29214Hamilton Mountain250 Fennell Ave. W.874214232935446129.379530
31129Toronto Downtown55 John St.863210182429385724.276480
33003Toronto EastKennedy Rd./Lawrence Ave. E.871711202632405926.177510
34021Toronto North4905 Dufferin St., ECCC87049192632416226.095529
35125Toronto West125 Resources Rd.86636162330395823.481471
44008BurlingtonNorth Shore Blvd. E./Lakeshore Rd.875712222834436328.386512
44017OakvilleEightLine/Glenashton Dr., Halton Res.873913222833416028.081511
44029Milton1120 Main St. E.85149212733426126.877490
45027OshawaBrittania Ave. W., EP Taylor Stables87549202733406226.488474
46090Brampton109 McLaughlin Rd. S.869212222935436228.483533
46108Mississauga3359 Mississauga Rd. N., U of T Campus87208202632405725.680470
47045Barrie83 Perry St.875010202632395525.970480
48006NewmarketEagle St. W./McCaffrey Rd.872214232934416028.587543
49005Parry Sound7 Bay St.871716253036435729.973500
49010Dorset1026 Bellwood Acres Rd.869410212834425327.166430
51001Ottawa DowntownRideau St./Wurtemburg St.877010192631395325.264510
51010PetawawaPetawawa Research Forest Facility877611212834415126.963450
52023Kingston23 Beechgrove Lane871517253035435830.172530
54012Belleville2 Sidney St., Water Treatment Plant874415243035436129.781531
56051CornwallBedford St./3rd St. W.871812212732405126.462480
59006Peterborough10 Hospital Dr.835114222833405427.687492
63203Thunder Bay421 James St. S.87568182429364422.956440
71078Sault Ste. MarieSault College875614232934405728.277580
75010North BayChippewa St. W., Dept. National Defence876410212732405226.274490
77233Sudbury155 Elm St.869810192531385124.862530

2020 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

IDCityLocationValid h10%30%50%70%90%99%MeanMax 10 minMax 1hMax 24hNumber of times above 10 min criteriaNumber of times above 1h criteriaNumber of times above annual criteria
12008Windsor Downtown467 University Ave. W.87070.00.00.10.20.84.30.3229.119.62.3000
12016Windsor WestCollege Ave./South St.83970.10.20.30.71.77.50.8146.232.28.2000
14111Sarnia700 Christina St. N.87180.00.10.20.53.537.61.9793.284.444.898740
29000Hamilton DowntownElgin St./Kelly St.87370.00.20.51.211.841.93.65144.589.730.81071090
29214Hamilton Mountain250 Fennell Ave. W.87340.00.00.20.88.228.72.45107.084.624.314200
34021Toronto North4905 Dufferin St., ECCC86940.00.00.00.10.41.80.1510.37.91.5000
35125Toronto West125 Resources Rd.85690.00.00.10.20.41.80.1913.810.01.6000
44029Milton1120 Main St. E.43670.30.40.50.61.33.4INS10.67.22.0000
51001Ottawa DowntownRideau St./Wurtemburg St.87690.00.00.10.10.30.80.125.14.00.8000
71078Sault Ste. MarieSault College87550.20.30.30.40.78.00.6348.229.85.3000
77233Sudbury155 Elm St.81290.10.20.30.41.712.00.90122.960.08.71530

2020 carbon monoxide (CO) annual statistics

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

IDCityLocationValid h10%30%50%70%90%99%MeanMax 1hMax 8hNumber of times above 1h criteriaNumber of times above 8h criteria
12008Windsor Downtown467 University Ave. W.84230.140.170.190.220.280.500.211.230.6900
29000Hamilton DowntownElgin St./Kelly St.87610.140.160.190.230.340.580.221.220.6900
34021Toronto North4905 Dufferin St., ECCC86180.140.160.180.210.270.440.191.000.8400
35125Toronto West125 Resources Rd.85040.150.180.200.230.310.540.221.551.1500
51001Ottawa DowntownRideau St./Wurtemburg St.86910.120.150.170.200.260.470.180.860.6500

2020 total reduced sulphur (TRS) compounds annual statistics

Unit: parts per billion (ppb)

IDCityLocationValid h10%30%50%70%90%99%MeanMax 1hMax 24h
12016Windsor WestCollege Ave./South St.84690000030.15264
14111Sarnia700 Christina St. N.77470000010.0721
29000Hamilton DowntownElgin St./Kelly St.87260000010.0341
71078Sault Ste. MarieSault College87240000010.0571

10-year trends

10-year trend for nitric oxide (NO)

Annual mean (ppb)

IDCity/Town2011201220132014201520162017201820192020Change
over
10 year
(%)
Trend
12008Windsor Downtown4.54.73.74.03.53.13.33.22.71.7-39.0SSS
12016Windsor West3.84.63.63.84.22.92.62.63.11.7-38.7SSS
13001Chatham1.91.81.61.51.71.41.91.81.41.5-3.4Non-SSS
14111Sarnia3.12.11.71.92.4INS1.51.81.71.6-14.1SSS
15020Grand Bend0.30.31.00.20.30.50.30.20.30.411.5Non-SSS
15026London3.34.21.41.31.41.01.00.80.90.7-52.3SSS
21005Brantford1.21.11.20.91.30.80.81.00.90.8-10.2Non-SSS
26060Kitchener2.02.11.61.61.61.31.00.91.20.7-28.4SSS
27067St. Catharines2.32.52.21.72.11.51.20.91.20.9-51.9SSS
28028Guelph2.32.21.11.21.31.11.11.20.90.8-37.0SSS
29000Hamilton Downtown4.84.64.33.91.34.23.93.94.02.9-18.3SSS
29118Hamilton West6.46.35.45.95.16.23.94.24.23.2-42.1SSS
29214Hamilton Mountain2.31.92.02.01.81.21.21.21.81.4-32.1SSS
33003Toronto East7.66.65.76.25.85.44.43.13.42.3-51.1SSS
34021Toronto North6.25.04.14.33.93.53.02.52.72.1-44.7SSS
35125Toronto West12.411.38.69.59.28.27.76.77.55.2-36.5SSS
44008Burlington4.64.64.64.63.93.93.42.73.02.3-44.5SSS
44017Oakville2.73.42.13.42.71.81.71.81.81.3-38.4SSS
44029Milton4.64.82.83.13.54.22.33.63.62.7-9.2SSS
45027Oshawa2.32.11.52.02.32.52.40.90.90.9-31.4SSS
46090Brampton4.64.44.64.03.83.42.22.22.21.4-49.7SSS
46108Mississauga4.13.83.12.93.13.62.01.62.61.4-39.0SSS
47045Barrie3.83.23.23.73.53.72.61.82.21.4-55.3SSS
48006Newmarket2.22.01.51.41.71.61.41.31.30.8-39.6SSS
49005Parry Sound0.90.50.50.60.80.60.50.50.70.4-12.5Non-SSS
51001Ottawa Downtown1.82.42.11.92.01.71.51.71.61.4-17.0SSS
52023Kingston0.50.40.20.80.90.70.60.60.60.721.6SSS
54012Belleville2.31.61.71.21.51.81.11.01.31.4-19.5SSS
56051Cornwall1.92.21.91.51.82.11.21.41.51.2-11.5SSS
59006Peterborough2.21.81.71.81.51.31.20.91.21.0-41.2SSS
63203Thunder Bay5.95.14.74.25.23.84.13.83.83.4-23.7SSS
71078Sault Ste. Marie2.01.71.32.01.71.01.31.21.51.6-29.3SSS
75010North Bay4.02.92.52.62.12.01.61.71.81.4-41.1SSS
77233SudburyN/AN/A2.93.32.93.32.52.32.82.4-22.9SSS

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 44029 was operated by the Halton Region prior to 2019.
  • 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).
  • Non-SSS - Non-Significant Sen's Slope (significant trend not detected).

10-year trend for nitrogen dioxide (NO2)

Annual mean (ppb)

IDCity/Town2011201220132014201520162017201820192020Change
over
10 year
(%)
Trend
12008Windsor Downtown14.513.212.414.012.711.411.111.010.99.0-26.9SSS
12016Windsor West12.911.411.511.811.410.69.98.810.08.1-31.3SSS
13001Chatham6.65.76.06.86.85.46.15.15.85.1-17.3SSS
14111Sarnia8.68.68.19.09.3INS7.37.66.85.9-22.9SSS
15020Grand Bend3.63.64.43.13.42.83.03.32.52.3-31.6SSS
15026London8.36.36.46.96.65.45.85.45.84.5-25.5SSS
21005Brantford6.15.44.85.55.54.84.45.25.64.3-11.6SSS
26060Kitchener7.77.16.77.06.86.25.85.86.34.9-22.5SSS
27067St. Catharines8.58.17.77.37.36.66.66.06.05.3-34.5SSS
28028Guelph7.36.56.67.16.36.25.95.95.44.9-24.5SSS
29000Hamilton Downtown13.511.912.412.412.211.911.911.612.59.9-14.1SSS
29118Hamilton West13.112.112.712.812.211.810.411.011.39.5-22.3SSS
29214Hamilton Mountain9.98.69.09.39.07.97.87.88.86.9-19.5SSS
33003Toronto East15.214.013.614.213.912.111.510.610.28.4-41.0SSS
34021Toronto North15.413.412.913.412.912.010.510.410.58.9-35.6SSS
35125Toronto West19.116.316.117.116.615.715.014.414.612.1-26.6SSS
44008Burlington11.811.011.010.910.410.29.79.49.68.2-22.5SSS
44017Oakville10.39.19.28.27.58.28.28.59.16.8-20.1SSS
44029Milton12.110.48.58.49.49.37.79.88.97.6-16.7SSS
45027Oshawa7.05.65.96.86.66.36.43.83.53.6-36.3SSS
46090Brampton11.310.49.110.69.99.78.38.18.66.8-31.4SSS
46108Mississauga10.69.69.59.29.28.68.07.28.46.7-27.9SSS
47045Barrie8.68.17.88.17.48.17.36.46.35.6-27.4SSS
48006Newmarket8.17.26.86.86.86.56.36.15.54.5-32.5SSS
49005Parry Sound3.63.32.93.33.22.92.72.92.62.4-26.6SSS
51001Ottawa Downtown7.97.87.97.47.46.97.17.36.75.9-20.9SSS
52023Kingston4.64.03.63.94.44.44.44.24.03.5-12.4SSS
54012Belleville6.34.74.74.54.85.14.33.74.23.5-23.1SSS
56051Cornwall6.56.16.25.65.35.55.05.15.04.6-19.4SSS
59006Peterborough4.33.75.05.35.14.54.74.53.94.1-25.9SSS
63203Thunder Bay8.67.37.37.87.57.16.77.56.76.1-19.6SSS
71078Sault Ste. Marie5.34.85.05.34.84.04.44.44.53.7-25.5SSS
75010North Bay7.46.15.85.65.64.74.64.95.14.3-26.5SSS
77233SudburyN/AN/A7.27.37.27.06.86.56.96.3-12.6SSS

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 44029 was operated by the Halton Region prior to 2019.
  • 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).

10-year trend for nitrogen oxides (NOx)

Annual mean (ppb)

IDCity/Town2011201220132014201520162017201820192020Change
over
10 year
(%)
Trend
12008Windsor Downtown18.917.816.218.016.214.514.414.213.610.7-31.1SSS
12016Windsor West16.716.015.215.715.513.512.511.313.09.9-34.2SSS
13001Chatham8.47.57.78.28.56.88.06.97.26.6-16.1SSS
14111Sarnia11.710.79.810.911.7INS8.79.48.57.5-23.3SSS
15020Grand Bend4.03.95.43.43.83.33.43.42.72.7-30.0SSS
15026London11.610.57.88.38.06.56.86.26.65.2-39.1SSS
21005Brantford7.36.75.76.46.85.75.36.26.55.1-10.6SSS
26060Kitchener9.69.28.38.58.47.56.96.77.45.5-25.6SSS
27067St. Catharines10.910.69.99.19.48.27.96.87.16.2-38.0SSS
28028Guleph9.58.87.88.47.77.37.07.16.45.6-28.3SSS
29000Hamilton Downtown18.316.616.816.37.716.115.815.516.512.8-17.1SSS
29118Hamilton West19.518.418.118.717.317.914.215.216.512.6-30.1SSS
29214Hamilton Mountain12.210.511.011.310.99.29.18.915.48.3-21.7SSS
33003Toronto East22.820.619.420.419.717.515.813.713.710.7-46.8SSS
34021Toronto North21.518.517.017.716.915.413.512.813.211.0-39.2SSS
35125Toronto West31.527.624.726.525.723.822.721.122.117.2-32.4SSS
44008Burlington16.415.615.615.514.314.213.212.012.610.5-29.9SSS
44017Oakville13.012.611.211.610.110.19.910.410.98.0-26.3SSS
44029Milton16.715.311.812.013.213.510.013.412.510.3-17.8SSS
45027Oshawa9.27.87.48.88.98.88.84.74.44.5-34.7SSS
46090Brampton15.914.813.914.613.713.110.610.310.748.1-38.6SSS
46108Mississauga14.713.412.612.112.312.29.98.810.978.0-33.9SSS
47045Barrie12.411.311.011.810.911.99.98.38.526.9-37.2SSS
48006Newmarket10.39.28.48.28.58.17.87.46.785.2-32.0SSS
49005Parry Sound4.53.83.44.04.03.63.33.33.342.8-24.2SSS
51001Ottawa Downtown9.710.210.19.39.58.68.69.08.317.3-22.6SSS
52023Kingston5.34.63.84.85.35.24.94.74.554.1-12.7SSS
54012Belleville8.76.46.35.76.26.75.44.75.534.9-22.1SSS
56051Cornwall8.48.48.07.07.17.66.26.36.545.8-20.2SSS
59006Peterborough6.65.46.67.16.65.95.85.35.145.0-27.9SSS
63203Thunder Bay14.512.412.011.912.71110.811.310.449.5-20.7SSS
71078Sault Ste. Marie7.26.46.37.36.65.15.85.65.955.2-26.0SSS
75010North Bay11.59.18.38.17.86.76.26.66.915.6-31.6SSS
77233SudburyN/AN/A10.110.610.210.29.48.89.78.7-15.8SSS

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 44029 was operated by the Halton Region prior to 2019.
  • 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).

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

Annual mean (µg/m3)

IDCity/Town2011201220132014201520162017201820192020Change
over
10 year
(%)
Trend
12008Windsor Downtown9.49.89.210.19.38.17.88.57.87.1-25.6SSS
12016Windsor West9.79.510.010.79.98.58.58.79.18.8-14.0SSS
13001Chatham8.27.58.18.68.16.66.46.86.86.7-20.0SSS
14111Sarnia12.912.78.59.08.4INS7.07.47.17.1-36.1SSS
15020Grand Bend7.67.47.38.17.76.05.15.65.44.8-42.7SSS
15026London7.78.19.18.88.37.17.07.36.76.5-27.7SSS
16015Port Stanley7.57.47.48.28.06.56.36.86.76.5-18.4SSS
18007Tiverton6.06.05.86.56.45.15.15.75.04.8-21.9SSS
21005Brantford8.27.88.59.28.77.37.27.77.46.7-18.7SSS
26060Kitchener7.77.78.79.38.87.37.07.47.26.6-20.8SSS
27067St. Catharines7.87.98.58.88.46.97.07.07.06.3-22.7SSS
28028Guelph7.47.48.18.98.46.96.87.47.16.9-12.6SSS
29000Hamilton Downtown10.010.210.110.810.28.28.59.28.88.1-24.0SSS
29118Hamilton West8.89.09.69.99.97.97.58.27.87.8-21.5SSS
29214Hamilton Mountain8.38.19.29.49.07.27.47.77.97.1-21.8SSS
33003Toronto East7.87.88.28.98.57.07.47.27.06.7-17.4SSS
34021Toronto North9.59.08.39.29.47.37.47.66.86.4-29.5SSS
35125Toronto West8.78.88.89.18.57.07.47.77.26.9-24.9SSS
44008Burlington7.88.08.79.69.47.67.07.27.06.4-28.7SSS
44017Oakville8.07.68.08.58.37.06.97.47.26.3-18.1SSS
44029Milton8.07.98.510.38.87.17.07.57.57.1-16.2SSS
45027Oshawa6.96.97.47.77.55.95.96.46.16.2-20.3SSS
46090Brampton7.67.28.58.98.46.87.07.36.86.7-17.3SSS
46108Mississauga7.77.57.98.78.57.26.87.37.06.6-18.1SSS
47045Barrie7.27.17.57.67.66.57.07.77.56.8-4.5Non-SSS
48006Newmarket6.97.17.37.37.16.05.96.45.95.9-21.1SSS
49005Parry Sound6.06.05.85.85.74.84.65.04.44.4-32.7SSS
49010Dorset5.45.35.45.35.64.64.64.94.14.5-19.5SSS
51001Ottawa Downtown6.36.27.07.06.95.95.95.95.96.0-13.6SSS
51010Petawawa4.54.84.84.74.84.44.13.63.84.2-22.8SSS
52023Kingston8.58.36.56.86.35.85.35.65.45.6-31.1SSS
54012Belleville6.26.56.96.86.65.55.86.46.16.3-6.6Non-SSS
56051Cornwall7.36.97.77.06.96.45.96.35.96.0-22.5SSS
59006Peterborough7.06.37.46.96.85.85.86.36.05.6-19.5SSS
63203Thunder Bay6.25.46.36.66.54.95.16.05.15.5-16.6SSS
71078Sault Ste. Marie5.75.65.66.05.94.95.05.54.84.5-18.6SSS
75010North Bay5.55.35.25.35.34.64.65.54.54.6-17.7SSS
77233Sudbury5.25.15.76.06.35.45.05.45.05.12.3Non-SSS

Notes:

  • From 2011-2012, 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 44029 was operated by the Halton Region prior to 2019.
  • 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.
  • Station 77233 replaced station 77219 as the Sudbury site in 2013.
  • SSS - Significant Sen's Slope (significant trend detected).
  • Non-SSS - Non-Significant Sen's Slope (significant trend not detected).

10-year trend for ground-level ozone (O3) 1h maximum

1h Maximum (ppb)
O3 1h AAQC: 80 ppb

IDCity/Town2011201220132014201520162017201820192020Change
over
10 year
(%)
Trend
12008Windsor Downtown1001288978899578898281-19.0Non-SSS
12016Windsor West1011288786879582908083-14.0SSS
13001Chatham921048578798490787677-16.3SSS
14111Sarnia9410183798383801018782-1.9Non-SSS
15020Grand Bend11512486908791821008593-15.7Non-SSS
15026London83888282778278767077-14.5SSS
16015Port Stanley941048587868490867776-19.1SSS
18007Tiverton899392868385821048175-15.2SSS
21005Brantford94887480798474767474-16.8SSS
26060Kitchener87897276768175757774-5.2Non-SSS
27067St. Catharines83989670738073757075-17.6Non-SSS
28028Guelph94947379798276787470-19.1SSS
29000Hamilton Downtown92888674747873776577-21.0SSS
29118Hamilton West88857870717874766576-15.3Non-SSS
29214Hamilton Mountain95918679797681807079-18.9SSS
33003Toronto East82898773919982726777-15.7Non-SSS
34021Toronto North85928782908582837795-7.1Non-SSS
35125Toronto West87948372827982767781-12.9SSS
44008Burlington85919273848088837486-6.6Non-SSS
44017Oakville959610172807484827181-17.8Non-SSS
44029Milton93949380807974817777-19.4SSS
45027Oshawa85929673738186766688-12.7Non-SSS
46090Brampton88928480847975837283-16.4SSS
46108Mississauga87818376797978796580-8.0Non-SSS
47045Barrie67917368807975727570-5.8Non-SSS
48006Newmarket8410572879294859188871.8Non-SSS
49005Parry Sound81947774867474806873-15.6SSS
49010Dorset72826979787469776466-12.5SSS
51001Ottawa Downtown66766764697371725764-6.8Non-SSS
51010Petawawa67776968706865665863-13.4SSS
52023Kingston80927981748294786872-16.9Non-SSS
54012Belleville86879280779686857381-10.5Non-SSS
56051Cornwall72767370697472685862-16.7SSS
59006Peterborough869074747885808668870.0Non-SSS
63203Thunder Bay60746370626251635656-22.5Non-SSS
71078Sault Ste. Marie80826673758070696177-11.3Non-SSS
75010North Bay74827271707869636374-12.2SSS
77233Sudbury67847673678069707562-13.4Non-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 44029 was operated by the Halton Region prior to 2019.
  • 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.
  • Station 77233 replaced station 77219 as the Sudbury site in 2013.
  • SSS - Significant Sen's Slope (significant trend detected).
  • Non-SSS - Non-Significant Sen's Slope (significant trend not detected).

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

Annual mean (ppb)

IDCity/Town2011201220132014201520162017201820192020Change
over
10 year
(%)
Trend
12008Windsor Downtown27.228.026.926.027.027.727.326.926.627.30.9Non-SSS
12016Windsor West26.428.026.727.226.527.727.027.027.326.01.2Non-SSS
13001Chatham29.729.529.629.329.629.629.528.729.229.1-1.9Non-SSS
14111Sarnia29.729.728.627.127.828.828.429.029.226.7-1.2Non-SSS
15020Grand Bend32.833.232.331.030.430.731.031.531.630.9-4.0SSS
15026London26.827.728.728.127.928.228.127.626.827.71.7Non-SSS
16015Port Stanley32.833.133.932.332.832.933.032.332.330.9-4.7SSS
18007Tiverton32.132.032.431.832.533.132.432.331.130.5-2.3Non-SSS
21005Brantford28.728.829.029.428.929.528.328.327.528.0-4.2SSS
26060Kitchener27.628.028.027.327.928.828.127.727.227.7-0.4Non-SSS
27067St. Catharines28.028.728.628.528.629.828.128.528.430.24.7SSS
28028Guelph28.928.829.027.827.728.728.428.926.327.0-4.1SSS
29000Hamilton Downtown25.425.725.025.325.926.725.625.624.426.32.4Non-SSS
29118Hamilton West24.224.224.422.723.924.425.025.523.625.24.0Non-SSS
29214Hamilton Mountain28.830.229.529.129.429.529.129.327.529.3-2.2Non-SSS
33003Toronto East23.324.624.123.423.525.524.425.224.626.110.0SSS
34021Toronto North23.625.725.325.325.725.924.025.524.126.04.3Non-SSS
35125Toronto West20.121.521.521.121.322.122.122.321.823.412.6SSS
44008Burlington25.926.726.425.526.527.627.127.626.628.39.1SSS
44017Oakville26.827.728.327.227.427.127.428.727.128.03.2Non-SSS
44029Milton25.726.527.627.127.227.227.528.126.926.84.0Non-SSS
45027Oshawa26.627.027.227.226.227.227.925.824.426.4-4.2SSS
46090Brampton26.126.626.726.526.527.127.228.626.528.48.5SSS
46108Mississauga24.125.625.225.425.426.026.226.124.525.63.7Non-SSS
47045Barrie25.326.325.525.625.425.925.927.525.725.93.2Non-SSS
48006Newmarket27.829.428.728.628.528.627.929.827.828.52.4Non-SSS
49005Parry Sound29.730.130.429.630.429.629.730.829.829.91.5Non-SSS
49010Dorset27.028.028.127.727.027.426.928.227.527.11.0Non-SSS
51001Ottawa Downtown24.226.025.624.825.625.625.526.425.925.24.4Non-SSS
51010Petawawa26.727.727.626.826.726.425.827.327.326.9-0.3Non-SSS
52023Kingston30.332.730.331.430.330.530.430.529.930.1-3.2Non-SSS
54012Belleville27.928.029.229.629.630.530.229.929.629.77.6SSS
56051Cornwall26.127.126.927.327.927.127.227.626.926.40.3Non-SSS
59006Peterborough27.929.128.629.229.329.728.929.728.327.60.6Non-SSS
63203Thunder Bay25.225.026.323.424.023.223.424.323.722.9-9.0SSS
71078Sault Ste. Marie27.828.828.928.427.827.328.129.728.128.20.6Non-SSS
75010North Bay26.726.127.426.727.026.426.426.026.426.2-1.8Non-SSS
77233Sudbury28.728.527.226.325.725.125.927.126.324.8-9.0SSS

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 44029 was operated by the Halton Region prior to 2019.
  • 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.
  • Station 77233 replaced station 77219 as the Sudbury site in 2013.
  • SSS - Significant Sen's Slope (significant trend detected).
  • Non-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)

IDCity/Town2011201220132014201520162017201820192020Change
over
10 year
(%)
Trend
12008Windsor Downtown33.836.832.530.933.333.432.833.731.432.7-3.3Non-SSS
12016Windsor West31.935.730.930.931.833.031.832.431.230.6-2.7Non-SSS
13001Chatham34.436.634.232.434.432.933.132.131.932.5-8.5SSS
14111Sarnia32.936.632.029.431.132.132.034.031.530.1-4.2Non-SSS
15020Grand Bend33.938.933.131.532.332.032.132.731.731.7-6.1SSS
15026London30.734.430.929.531.030.429.830.527.429.1-9.7SSS
16015Port Stanley35.538.436.933.735.635.235.035.333.732.8-12.1SSS
18007Tiverton31.736.032.530.833.334.132.232.929.730.5-8.2Non-SSS
21005Brantford31.133.530.129.931.232.229.430.428.329.5-8.6Non-SSS
26060Kitchener30.233.529.828.530.231.829.830.629.229.6-2.7Non-SSS
27067St. Catharines31.235.031.229.531.733.229.831.329.732.6-1.3Non-SSS
28028Guelph31.334.530.428.930.231.229.631.727.329.0-8.1Non-SSS
29000Hamilton Downtown28.732.428.427.529.530.627.829.726.129.4-4.9Non-SSS
29118Hamilton West26.229.226.422.726.527.126.828.524.427.73.6Non-SSS
29214Hamilton Mountain32.337.432.531.633.933.231.534.029.632.3-7.0Non-SSS
33003Toronto East27.430.627.125.927.729.726.029.226.028.8-4.1Non-SSS
34021Toronto North27.532.729.428.630.730.726.330.425.929.3-6.5Non-SSS
35125Toronto West23.627.524.423.525.025.924.326.324.325.96.5Non-SSS
44008Burlington29.232.529.227.430.130.529.031.828.831.25.6Non-SSS
44017Oakville29.934.230.628.330.229.929.532.428.830.4-4.4Non-SSS
44029Milton29.232.230.628.230.430.629.634.328.928.6-7.7Non-SSS
45027Oshawa28.531.128.327.928.929.428.626.624.427.4-10.8Non-SSS
46090Brampton29.332.729.528.930.331.229.532.728.231.01.3Non-SSS
46108Mississauga26.730.426.526.528.028.527.228.324.927.0-2.8Non-SSS
47045Barrie26.229.725.625.426.827.425.629.024.725.8-3.8Non-SSS
48006Newmarket30.534.230.329.431.231.729.033.228.430.1-5.8Non-SSS
49005Parry Sound28.732.830.128.231.428.927.730.927.828.5-5.0Non-SSS
49010Dorset23.828.325.324.424.625.123.025.823.923.7-5.8Non-SSS
51001Ottawa Downtown25.129.326.524.627.827.525.327.625.625.7-2.9Non-SSS
51010Petawawa22.828.124.522.924.423.421.123.722.922.7-10.1Non-SSS
52023Kingston32.038.532.432.732.233.330.933.130.031.3-6.5Non-SSS
54012Belleville29.932.730.630.433.233.730.932.430.031.01.7Non-SSS
56051Cornwall26.730.728.127.029.728.727.129.426.126.3-7.1Non-SSS
59006Peterborough29.834.229.530.031.532.329.232.228.128.4-6.3Non-SSS
63203Thunder Bay24.225.324.722.723.622.020.422.121.821.3-17.7SSS
71078Sault Ste. Marie26.430.328.227.428.126.326.329.126.226.4-5.4Non-SSS
75010North Bay26.328.526.926.227.826.424.726.325.724.4-8.9SSS
77233Sudbury26.929.828.027.027.726.625.828.825.923.7-12.3Non-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 44029 was operated by the Halton Region prior to 2019.
  • 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.
  • Station 77233 replaced station 77219 as the Sudbury site in 2013.
  • SSS - Significant Sen's Slope (significant trend detected).
  • Non-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)

IDCity/Town2011201220132014201520162017201820192020Change
over
10 year
(%)
Trend
12008Windsor Downtown22.521.722.822.822.423.623.322.423.123.54.6Non-SSS
12016Windsor West22.522.323.424.522.723.923.623.124.422.83.3Non-SSS
13001Chatham26.724.326.227.126.327.226.826.227.426.72.1Non-SSS
14111Sarnia27.424.726.225.425.4INS26.025.427.624.3-1.9Non-SSS
15020Grand Bend32.129.131.830.629.129.830.230.731.630.5-0.6Non-SSS
15026London24.222.926.927.125.826.626.925.626.426.77.1Non-SSS
16015Port Stanley31.029.331.831.331.231.231.530.231.429.6-1.8Non-SSS
18007Tiverton32.229.232.432.731.932.432.631.932.130.6-0.9Non-SSS
21005Brantford27.125.428.328.827.227.727.526.726.927.0-1.9Non-SSS
26060Kitchener25.724.026.726.526.126.627.125.625.826.42.3Non-SSS
27067St. Catharines25.824.126.827.926.327.227.026.427.528.58.8SSS
28028Guelph27.224.828.027.026.026.827.526.925.725.6-3.3Non-SSS
29000Hamilton Downtown23.120.922.523.723.323.924.222.623.224.16.3Non-SSS
29118Hamilton West22.720.623.022.822.122.523.723.323.023.54.7SSS
29214Hamilton Mountain26.325.027.327.326.326.827.425.925.927.21.2Non-SSS
33003Toronto East20.420.322.021.620.522.523.322.423.524.218.6SSS
34021Toronto North20.820.722.322.822.122.622.322.022.823.710.2SSS
35125Toronto West17.717.219.519.418.619.420.519.420.121.618.5SSS
44008Burlington23.522.524.424.123.825.625.724.725.226.212.8SSS
44017Oakville24.723.126.626.525.325.125.926.026.026.35.9Non-SSS
44029Milton23.322.225.526.324.924.725.924.925.525.68.5Non-SSS
45027Oshawa25.224.126.426.724.325.627.325.424.525.72.2Non-SSS
46090Brampton23.822.224.624.823.824.125.625.625.326.511.1SSS
46108Mississauga22.522.224.324.723.624.225.524.624.224.79.7Non-SSS
47045Barrie24.723.925.525.824.424.826.326.526.426.17.1SSS
48006Newmarket25.826.027.528.126.626.327.227.327.327.56.0Non-SSS
49005Parry Sound30.428.130.630.629.830.031.130.731.331.03.5SSS
49010Dorset29.527.730.130.128.829.029.630.030.129.52.4Non-SSS
51001Ottawa Downtown23.623.524.925.124.024.325.625.526.224.97.4SSS
51010Petawawa29.527.529.929.628.528.629.329.830.430.03.9Non-SSS
52023Kingston29.028.628.830.428.928.530.228.629.929.20.8Non-SSS
54012Belleville26.424.628.229.127.028.229.728.129.328.711.5Non-SSS
56051Cornwall25.724.225.727.626.626.027.426.327.526.54.1Non-SSS
59006Peterborough26.625.528.028.627.727.828.727.928.527.32.9Non-SSS
63203Thunder Bay26.124.727.423.824.224.225.625.925.124.1-2.4Non-SSS
71078Sault Ste. Marie28.927.629.429.227.728.029.530.229.529.63.2SSS
75010North Bay27.024.427.827.126.426.427.625.926.927.41.2Non-SSS
77233Sudbury30.027.626.625.824.324.026.126.026.725.7-4.4Non-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 44029 was operated by the Halton Region prior to 2019.
  • 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.
  • Station 77233 replaced station 77219 as the Sudbury site in 2013.
  • SSS - Significant Sen's Slope (significant trend detected).
  • Non-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

IDCity/Town2011201220132014201520162017201820192020Change
over
10 year
(%)
Trend
12008Windsor Downtown3.52.82.42.41.91.11.00.60.40.3-86.7SSS
12016Windsor West3.42.82.62.81.91.40.90.70.80.8-76.2SSS
14111Sarnia5.34.13.83.53.2INS1.71.91.92.0-50.4SSS
29000Hamilton Downtown5.24.84.85.14.33.23.55.04.83.7-19.9SSS
29214Hamilton Mountain4.13.72.82.92.61.81.82.43.52.5-29.2SSS
35125Toronto West1.50.60.60.71.00.60.50.30.30.2-52.2SSS
44029Milton1.01.31.21.31.10.90.70.7INSINS-34.6SSS
51001Ottawa Downtown0.40.30.30.30.400.10.20.20.1-25.0SSS
71078Sault Ste. Marie0.80.60.80.80.80.60.70.80.70.6-11.8Non-SSS
77233Sudbury1.51.32.82.42.42.11.31.21.20.9-60.0SSS

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 44029 was operated by the Halton Region prior to 2019.
  • SSS - Significant Sen's Slope (significant trend detected).
  • Non-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

IDCity/Town2011201220132014201520162017201820192020Change
over
10 year
(%)
Trend
12008Windsor Downtown3.82.11.91.81.92.32.61.92.31.2-23.1Non-SSS
29000Hamilton Downtown1.81.72.02.91.31.42.11.71.91.2-19.7Non-SSS
35125Toronto West1.41.41.41.61.31.71.20.91.51.66.5Non-SSS
51001Ottawa Downtown1.50.90.90.80.80.90.71.00.70.9-22.2Non-SSS

Note:

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

10-year trend for benzene

Annual mean (µg/m3)
Benzene 1y AAQC: 0.45 µg/m3

IDCity/Town2010201120122013201420152016201720182019Change
over
10 year
(%)
Trend
12016Windsor West0.687INS0.5580.5190.6100.5660.5210.4500.4780.445-28.9SSS
14111Sarnia0.961INS0.9000.8201.0071.1910.6890.6040.5740.419-42.3SSS
15026London0.490INS0.4550.4130.4460.4510.3410.3390.3210.296-39.5SSS
26060Kitchener0.537INS0.479N/A0.4830.5480.3950.4460.3550.290-41.6SSS
29000Hamilton Downtown1.060INS0.977INS0.8991.0920.6750.5690.6390.568-35.1SSS
48006Newmarket0.416N/A0.3710.4060.4220.4250.3280.385INS0.250-32.4SSS
51001Ottawa Downtown0.4510.4180.4220.4420.4130.4530.3650.3880.4050.323-20.7SSS

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)

IDCity/Town2010201120122013201420152016201720182019Change
over
10 year
(%)
Trend
12016Windsor West1.679INS1.3921.0171.5421.2481.2720.9721.1310.797-35.7SSS
14111Sarnia2.037INS2.5391.5871.9082.3501.7781.5501.0140.779-41.1SSS
15026London1.334INS1.4080.8870.8391.0130.7270.6330.6570.491-50.9SSS
26060Kitchener1.477INS1.322N/A1.2781.0521.0201.0020.6250.572-47.7SSS
29000Hamilton Downtown2.842INS2.067INS2.2292.2491.6421.2960.8620.817-47.2SSS
48006Newmarket0.878N/A0.8770.9160.7321.3401.1180.807INS0.418-30.8SSS
51001Ottawa Downtown1.2120.9290.8990.9750.7410.9820.9020.8260.7040.618-29.4SSS

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)

IDCity/Town2010201120122013201420152016201720182019Change
over
10 year
(%)
Trend
12016Windsor West0.275INS0.2210.1790.2670.2380.2340.1810.1870.137-37.4SSS
14111Sarnia0.392INS0.2780.2550.2530.3620.2820.2110.2350.118-36.6SSS
15026London0.190INS0.1430.1250.1210.1490.1080.1050.1410.070-43.5SSS
26060Kitchener0.220INS0.162N/A0.1670.1680.1590.1640.1090.079-37.9SSS
29000Hamilton Downtown0.278INS0.193INS0.1920.2100.1860.1870.1290.126-28.7SSS
48006Newmarket0.154N/A0.1150.1340.1250.2490.2150.130INS0.067-29.4SSS
51001Ottawa Downtown0.1440.1220.1050.1120.0990.1230.1190.1200.0880.064-24.9SSS

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 m- and p-xylene

Annual mean (µg/m3)

IDCity/Town2010201120122013201420152016201720182019Change
over
10 year
(%)
Trend
12016Windsor West0.818INS0.6890.5360.8250.7020.6350.5050.5020.409-41.9SSS
14111Sarnia0.790INS0.6760.5100.6290.8500.4950.4990.5630.256-32.3SSS
15026London0.500INS0.3880.3450.3180.3980.2670.2680.4070.200-38.2SSS
26060Kitchener0.639INS0.478N/A0.4690.4640.4340.4510.2760.223-39.1SSS
29000Hamilton Downtown0.842INS0.603INS0.5940.6210.5180.5320.3590.398-30.2SSS
48006Newmarket0.437N/A0.3330.3620.3340.5820.4840.350INS0.191-33.6SSS
51001Ottawa Downtown0.4290.3550.3100.3290.3090.3630.3380.3340.2220.186-30.6SSS

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 o-xylene

Annual mean (µg/m3)

IDCity/Town2010201120122013201420152016201720182019Change
over
10 year
(%)
Trend
12016Windsor West0.255INS0.2280.1840.2830.2390.2320.1900.1840.147-32.2SSS
14111Sarnia0.262INS0.2440.1710.2260.3130.1780.1920.2130.101-30.2SSS
15026London0.147INS0.1260.1180.1130.1460.1030.1030.1480.074-31.8SSS
26060Kitchener0.188INS0.157N/A0.1660.1640.1530.1640.1070.082-40.9SSS
29000Hamilton Downtown0.241INS0.195INS0.2060.2160.1890.1980.1310.145-18.5SSS
48006Newmarket0.133N/A0.1160.1260.1340.2180.1920.128INS0.068-24.8N-SSS
51001Ottawa Downtown0.1470.1280.1180.1180.1110.1360.1270.1320.0890.078-18.5SSS

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

10-year trend for 1,3-butadiene

Annual mean (µg/m3)
1,3-butadiene 1y AAQC: 2.0 µg/m3

IDCity/Town2010201120122013201420152016201720182019Change
over
10 year
(%)
Trend
12016Windsor West0.056INS0.0480.0360.0420.0350.0320.0340.0280.028-41.0SSS
14111Sarnia0.167INS0.2050.2090.1240.2160.0890.0770.0880.054-46.8SSS
15026London0.050INS0.0400.0230.0250.0260.0200.0350.0250.025-36.0SSS
26060Kitchener0.056INS0.042N/A0.0290.0290.0230.0380.0260.025-35.1SSS
29000Hamilton Downtown0.060INS0.046INS0.0320.0370.0250.0390.0280.028-31.5SSS
48006Newmarket0.051N/A0.0390.0210.0200.0280.0240.035INS0.025-32.2SSS
51001Ottawa Downtown0.0520.0410.0400.0350.0260.0300.0270.0370.0320.027-36.9SSS

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

PM2.5 and ozone CAAQS metric values for designated sites across Ontario (2020)

Air zone areaCity/Town24-hour PM2.5
(μg/m3)
Annual PM2.5
(μg/m3)
8-hour ozone
(ppb)
SarniaSarnia197.272*(41)
HamiltonHamilton Downtown228.762(48)
HamiltonHamilton Mountain198.666*(51)
SudburySudbury145.260(45)
Sault Ste. MarieSault Ste. Marie134.960(46)
Northern OntarioThunder Bay145.550(46)
Southern OntarioWindsor Downtown197.871*(42)
Southern OntarioChatham176.863*(42)
Southern OntarioLondon186.864*(49)
Southern OntarioBrantford187.363*(49)
Southern OntarioKitchener197.162(49)
Southern OntarioGuelph207.161(51)
Southern OntarioSt. Catharines176.862(49)
Southern OntarioBurlington186.965*(53)
Southern OntarioOakville186.965*(50)
Southern OntarioMilton197.465*(52)
Southern OntarioMississauga187.061(47)
Southern OntarioBrampton197.066*(52)
Southern OntarioToronto West187.263*(48)
Southern OntarioToronto DowntownINSINSINS
Southern OntarioToronto North197.066*(51)
Southern OntarioToronto East197.061(45)
Southern OntarioOshawa176.262(48)
Southern OntarioBarrie207.060(47)
Southern OntarioPeterborough176.061(48)
Southern OntarioKingston145.563*(47)
Southern OntarioOttawa Downtown165.955(47)

Note:

  • Designated sites normally refer to communities with populations greater than 100,000.
  • The CAAQS for 24h PM2.5 is 27 μg/m3 based on the 98th percentile measurement annually, averaged over three consecutive years.
  • The CAAQS for annual PM2.5 is 8.8 μg/m3 based on the annual average of the daily 24-hour average concentrations averaged over three consecutive years.
  • The CAAQS for ozone is 62 ppb based on the consecutive three-year average of the annual 4th highest daily maximum eight-hour running average.
  • An asterisk denotes an exceedance of the CAAQS.
  • INS denotes insufficient data to report a valid CAAQS metric.
  • Value in parenthesis is the calculated 8h ozone CAAQS metric once the transboundary influence was removed.

NO2 and SO2 CAAQS metric values for designated sites across Ontario (2020)

Air zone areaCity/Town1-hour NO2 (ppb)Annual NO2 (ppb)1-hour SO2 (ppb)Annual SO2 (ppb)
SarniaSarnia365.9612.0
HamiltonHamilton Downtown439.987*3.7
HamiltonHamilton Mountain416.9572.5
SudburySudbury496.3460.9
Sault Ste. MarieSault Ste. Marie323.7370.6
Northern OntarioThunder Bay426.1N/AN/A
Southern OntarioWindsor Downtown449.0150.3
Southern OntarioChatham315.1N/AN/A
Southern OntarioLondon314.5N/AN/A
Southern OntarioBrantford284.3N/AN/A
Southern OntarioKitchener364.9N/AN/A
Southern OntarioGuelph344.9N/AN/A
Southern OntarioSt. Catharines345.3N/AN/A
Southern OntarioBurlington438.2N/AN/A
Southern OntarioOakville436.8N/AN/A
Southern OntarioMilton517.6N/AN/A
Southern OntarioMississauga386.7N/AN/A
Southern OntarioBrampton456.8N/AN/A
Southern OntarioToronto West5112.170.2
Southern OntarioToronto DowntownINS12.3N/AN/A
Southern OntarioToronto North458.950.1
Southern OntarioToronto East478.4N/AN/A
Southern OntarioOshawa233.6N/AN/A
Southern OntarioBarrie405.6N/AN/A
Southern OntarioPeterborough344.0N/AN/A
Southern OntarioKingston323.5N/AN/A
Southern OntarioOttawa Downtown415.920.1

Note:

  • Designated sites normally refer to communities with populations greater than 100,000.
  • The CAAQS for 1h NO2 is 60 ppb is based on the 3-year average of the annual 98th percentile of the daily maximum 1-hour average NO2 concentrations.
  • The CAAQS for annual NO2 is 17.0 ppb based on the average over a single calendar year of all the 1h average NO2 concentrations.
  • The CAAQS for 1h SO2 is 70 ppb based on the 3-year average of the annual 99th percentile of the SO2 daily maximum 1-hour average concentrations.
  • The CAAQS for annual SO2 is 5.0 ppb based on the average over a single calendar year of all 1h average SO2 concentrations.
  • An asterisk denotes an exceedance of the CAAQS.
  • INS denotes insufficient data to report a valid CAAQS metric.
  • N/A denotes not applicable (parameter not monitored at location).

PM2.5 and ozone CAAQS metric trends for designated sites across Ontario (2011-2020)

Air zone areaCity/Town10-year trend (%) based on
24-hour PM2.5
10-year trend (%) based on
annual PM2.5
10-year trend (%) based on
8-hour ozone
SarniaSarnia-34.5-50.00.0*
HamiltonHamilton Downtown-27.0-14.5-7.5
HamiltonHamilton Mountain-13.6-9.6*-7.7
SudburySudbury0.0*-15.0-11.9
Sault Ste. MarieSault Ste. Marie-24.1-14.3*-10.9
Northern OntarioThunder Bay-11.3-8.0*-11.1
Southern OntarioWindsor Downtown-18.8-19.1-9.6
Southern OntarioChatham-21.4-19.4-16.7
Southern OntarioLondon-12.9*-17.8-11.9*
Southern OntarioBrantford-20.5-11.2*-14.1
Southern OntarioKitchener-14.3-10.2*-8.2
Southern OntarioGuelph-7.1*-3.5*-13.0
Southern OntarioSt. Catharines-21.4-17.3-10.7
Southern OntarioBurlington-20.5-14.4*-3.4*
Southern OntarioOakville-12.9-10.8*-6.5
Southern OntarioMilton-10.7*-7.4*-4.3
Southern OntarioMississauga-14.3*-8.5*-6.9
Southern OntarioBrampton-6.1*-6.2*-3.3*
Southern OntarioToronto West-18.4-22.0-11.3
Southern OntarioToronto DowntownINSINSINS
Southern OntarioToronto North-27.7-23.30.0*
Southern OntarioToronto East-13.6-13.0-10.2
Southern OntarioOshawa-16.9-14.9*-9.9
Southern OntarioBarrie0.0*3.7*-9.7
Southern OntarioPeterborough-22.5-11.7-12.7
Southern OntarioKingston-50.4-39.8-12.2
Southern OntarioOttawa Downtown-21.4-8.4*-5.2*

Notes:

  • Designated sites normally refer to communities with populations greater than 100,000.
  • *Non-Significant Sen’s Slope (significant trend not detected).
  • INS denotes insufficient data for a valid 10-year trend.

NO2 and SO2 CAAQS metric trends for designated sites across Ontario (2011-2020)

Air zone areaCity/Town10-year trend (%) based on
1-hour NO2
10-year trend (%) based on
annual NO2
10-year trend (%) based on
1-hour SO2
10-year trend (%) based on
annual SO2
SarniaSarnia0.0*-22.9-40.6-50.4
HamiltonHamilton Downtown-9.4-14.115.0*-19.9
HamiltonHamilton Mountain0.0*-19.5-36.0-29.2
SudburySudburyINS-12.6-29.2*-60.0
Sault Ste. MarieSault Ste. Marie-11.8-25.5-5.1*-11.8*
Northern OntarioThunder Bay0.0*-19.6N/AN/A
Southern OntarioWindsor Downtown-19.0-26.9-77.6-86.7
Southern OntarioChatham-12.5-17.3N/AN/A
Southern OntarioLondon-20.0-25.5N/AN/A
Southern OntarioBrantford-23.7-11.6N/AN/A
Southern OntarioKitchener-20.0-22.5N/AN/A
Southern OntarioGuelph-14.8-24.5N/AN/A
Southern OntarioSt. Catharines-15.0-34.5N/AN/A
Southern OntarioBurlington-7.5-22.5N/AN/A
Southern OntarioOakville-12.5-20.1N/AN/A
Southern OntarioMilton0.0*-16.7-37.0*-34.6
Southern OntarioMississauga-15.7-27.9N/AN/A
Southern OntarioBrampton-11.5-31.4N/AN/A
Southern OntarioToronto West-12.2-26.6-46.2-52.2
Southern OntarioToronto DowntownINSINSINSINS
Southern OntarioToronto North-11.3-35.6N/AN/A
Southern OntarioToronto East-6.8*-41.0N/AN/A
Southern OntarioOshawa-7.9*-36.3N/AN/A
Southern OntarioBarrie-5.6*-27.4N/AN/A
Southern OntarioPeterborough0.0*-25.9N/AN/A
Southern OntarioKingston0.0*-12.4N/AN/A
Southern OntarioOttawa Downtown0.0*-20.9-56.3-25.0

Notes:

  • Designated sites normally refer to communities with populations greater than 100,000.
  • *Non-Significant Sen’s Slope (significant trend not detected).
  • INS denotes insufficient data for a valid 10-year trend.
  • N/A denotes not applicable (parameter not monitored at location).
  • Milton is based on 8 years of available data.

Management levels for Canadian Ambient Air Quality Standard pollutants

Ozone

Management level8-hour
2020
Red> 62 ppb
Orange57 to 62 ppb
Yellow51 to 56 ppb
Green≤ 50 ppb

Fine particulate matter (PM2.5)

Management Level24-hour
2020
Annual
2020
Red> 27 µg/m3> 8 µg/m3
Orange20 to 27 µg/m36.5 to 8.8 µg/m3
Yellow11 to 19 µg/m34.1 to 6.4 µg/m3
Green≤ 10 µg/m3≤ 4.0 µg/m3

Sulphur dioxide (SO2)

Management Level1-hour
2020
Annual
2020
Red> 70 ppb> 5.0 ppb
Orange51 to 70 ppb3.1 to 5.0 ppb
Yellow31 to 50 ppb2.1 to 3.0 ppb
Green≤ 30 ppb≤ 2.0 ppb

Nitrogen dioxide (NO2)

Management Level1-hour
2020
Annual
2020
Red> 60 ppb> 17.0 ppb
Orange32 to 60 ppb7.1 to 17.0 ppb
Yellow21 to 30 ppb2.1 to 7.0 ppb
Green≤ 20 ppb≤ 2.0 ppb

AQHI and Air Quality Alert Program Reporting

2020 Air Quality Health Index summary

Station IDCity/TownNo. of valid hoursLow risk AQHI=1Low risk AQHI=2Low risk AQHI=3Moderate risk AQHI=4Moderate risk AQHI=5Moderate risk AQHI=6High risk AQHI=7High risk AQHI=8High risk AQHI=9High risk AQHI=10Very high risk AQHI=+No. of days at least 1 hour > 6
12008Windsor Downtown87142.9051.5438.546.610.4000.0100001
12016Windsor West83704.1753.7336.505.200.3800.0200001
13001Chatham86999.9261.1324.963.810.180000000
14111Sarnia872911.5161.9021.464.400.7200.0100001
15020Grand Bend862117.0966.3714.072.180.1500.1400005
15026London861914.2962.1521.262.260.030000000
16015Port Stanley855914.2461.9520.762.800.250000000
18007Tiverton833914.6467.8615.731.730.040000000
21005Brantford865714.0160.8822.432.620.060000000
26060Kitchener867912.7061.8023.422.030.050000000
27067St. Catharines86857.2958.6330.743.290.050000000
28028Guelph869614.2061.2821.812.640.060000000
29000Hamilton Downtown87373.5546.1840.478.470.980.34000000
29118Hamilton West86085.9649.7236.806.660.760.10000000
29214Hamilton Mountain87405.9052.7133.926.700.660.09000000
31129Toronto Downtown85973.4341.2943.649.561.880.19000000
33003Toronto East87227.4455.0031.095.820.600.05000000
34021Toronto North86848.6550.2634.555.780.630.020.1000004
35125Toronto West86123.8945.0542.867.370.690.130.0100001
44008Burlington87525.1251.5136.795.920.6400.0200001
44017Oakville86717.6157.8429.964.170.4000.0100001
44029Milton84517.0355.5132.274.720.470000000
45027Oshawa847722.5161.2713.852.010.310.010.0500001
46090Brampton87238.7753.9031.514.950.8300.0300002
46108Mississauga872811.7060.5524.533.000.220000000
47045Barrie834717.7355.1623.673.280.160000000
48006Newmarket874715.0859.4522.572.620.2500.0300003
49005Parry Sound867421.9660.1816.661.190.010000000
49010Dorset862326.5858.4814.450.480.010000000
51001Ottawa Downtown872019.7154.2723.202.580.240000000
51010Petawawa856028.7957.2113.660.3500000000
52023Kingston858613.7263.9220.242.1200000000
54012Belleville857713.2063.0420.792.890.0700.0100001
56051Cornwall872718.5561.8017.541.960.150000000
59006Peterborough837620.4958.3918.822.160.1200.0200001
63203Thunder Bay870122.8060.1415.441.450.170000000
71078Sault Ste. Marie850621.5361.1115.871.400.090000000
75010North Bay874324.8559.1614.721.250.020000000
77233Sudbury873421.4255.6119.912.860.190000000

2020 air quality alert summary

Air quality forecast regionSpecial air quality statementSmog and air health advisory
Algonquin00
Atikokan - Upsala - Quetico00
Attawapiskat00
Bancroft - Bon Echo Park00
Barrie - Orillia - Midland00
Belleville - Quinte - Northumberland00
Big Trout Lake - Sachigo Lake00
Brockville - Leeds and Grenville00
Burk's Falls - Bayfield Inlet00
Chapleau - Gogama00
City of Hamilton00
City of Ottawa00
City of Thunder Bay00
City of Toronto20
Cornwall - Morrisburg00
Dryden - Ignace00
Dufferin - Innisfil00
Dunnville - Caledonia - Haldimand00
Elgin10
Elliot Lake - Ranger Lake00
Fort Frances - Rainy Lake00
Fort Hope - Webequie10
Fort Severn00
Geraldton - Manitouwadge - Hornepayne10
Greater Sudbury and Vicinity00
Grey - Bruce00
Haliburton00
Halton - Peel20
Huron - Perth20
Kapuskasing - Hearst00
Kenora - Nestor Falls00
Kingston - Prince Edward00
Kirkland Lake - New Liskeard - Temagami00
Lake Nipigon - Wabakimi00
London - Middlesex10
Manitoulin - Northshore - Killarney00
Moosonee - Fort Albany00
Niagara00
Nipigon - Marathon - Superior North00
North Bay - West Nipissing00
Oxford - Brant00
Parry Sound - Muskoka00
Peawanuck00
Peterborough - Kawartha Lakes00
Pickle Lake - Wunnummin Lake10
Prescott and Russell00
Red Lake - Ear Falls10
Renfrew - Pembroke - Barry's Bay00
Sandy Lake - Pikangikum10
Sarnia - Lambton40
Sault Ste. Marie - Superior East00
Simcoe - Delhi - Norfolk00
Sioux Lookout - Savant Lake00
Smiths Falls - Lanark - Sharbot Lake00
Stirling - Tweed - South Frontenac00
Superior West00
Timmins - Cochrane00
Waterloo - Wellington00
Wawa - White River - Pukaskwa00
Windsor - Essex - Chatham - Kent40
York - Durham20
Ontario60

COVID‑19 pandemic period

Traffic volumes and air pollution concentrations in baseline years and changes in 2020 at the Highway 401 roadside station

Means in baseline years
ParameterPre-COVID periodStay-at-home periodRe-opening period
Car volume (counts/hour)734075697639
Truck volume (counts/hour)114613531302
BC (µg/m3)1.21.21.6
NO2 (ppb)22.619.217.2
PM2.5 (µg/m3)10.68.08.8
O3 (ppb)18.224.017.4
Changed means in 2020 relative to the baseline years
ParameterPre-COVID periodStay-at-home periodRe-opening period
Car volume (counts/hour)134-2349-924
Truck volume (counts/hour)13-28111
BC (µg/m3)0.05-0.27-0.30
NO2 (ppb)-2.2-4.2-2.3
PM2.5 (µg/m3)-1.6-1.20.4
O3 (ppb)-0.5-0.51.1
Changes attributable to the pandemic (%)
ParameterStay-at-home periodRe-opening period
Car volume (counts/hour)-33%-14%
Truck volume (counts/hour)-22%0%
BC (µg/m3)-27%-23%
NO2 (ppb)-10%0%
PM2.5 (µg/m3)6%23%
O3 (ppb)0%9%

Notes:

  • Baseline years: 2017-2019.
  • Pre-COVID period: January 1 - March 18; Stay-at-home period: March 19 - May 18; Re-opening period: May 19 - December 31.

Baseline concentrations of black carbon and changes in 2020

Means in baseline years (µg/m3)
IDCity/TownPre-COVID periodStay-at-home periodRe-opening period
12008Windsor Downtown0.40.40.6
29000Hamilton Downtown0.50.70.8
33003Toronto East0.40.40.6
34021Toronto North0.40.40.6
35033Etobicoke South0.70.80.9
83126Highway 4011.21.21.6
Changed means in 2020 relative to the baseline years (µg/m3)
IDCity/TownPre-COVID periodStay-at-home periodRe-opening period
12008Windsor Downtown0-0.14-0.16
29000Hamilton Downtown0.02-0.18-0.15
33003Toronto East0.02-0.07-0.09
34021Toronto North0.06-0.08-0.05
35033Etobicoke South0.07-0.080.03
83126Highway 4010.05-0.27-0.30
Changes attributable to the pandemic (%)
IDCity/TownStay-at-home periodRe-opening period
12008Windsor Downtown-34%-25%
29000Hamilton Downtown-28%-22%
33003Toronto East-24%-19%
34021Toronto North-31%-17%
35033Etobicoke South-20%-4%
83126Highway 401-27%-23%

Notes:

  • Baseline years: 2017-2019.
  • Pre-COVID period: January 1 - March 18; Stay-at-home period: March 19 - May 18; Re-opening period: May 19 - December 31.

Baseline concentrations of nitrogen dioxide and changes in 2020

Means in baseline years (ppb)
IDCity/TownPre-COVID periodStay-at-home periodRe-opening period
12008Windsor Downtown14.210.210.1
29000Hamilton Downtown13.613.011.2
29118Hamilton West12.411.710.2
33003Toronto East13.89.910.0
34021Toronto North13.69.89.7
35033Etobicoke South17.415.414.0
35125Toronto West18.214.013.6
63203Thunder Bay11.07.65.4
75010North Bay8.14.83.8
83126Highway 40122.619.217.2
Changed means in 2020 relative to the baseline years (ppb)
IDCity/TownPre-COVID periodStay-at-home periodRe-opening period
12008Windsor Downtown3.1-2.6-1.9
29000Hamilton Downtown-1.7-3.0-2.3
29118Hamilton West-1.4-2.1-1.4
33003Toronto East-2.7-3.1-2.2
34021Toronto North-2.0-2.1-1.4
35033Etobicoke South-1.3-3.7-2.9
35125Toronto West-1.8-3.5-2.8
63203Thunder Bay-1.1-1.6-0.5
75010North Bay-1.1-1.4-0.4
83126Highway 401-2.2-4.2-2.3
Changes attributable to the pandemic (%)
IDCity/TownStay-at-home periodRe-opening period
12008Windsor Downtown-1%6%
29000Hamilton Downtown-10%-5%
29118Hamilton West-6%0%
33003Toronto East-5%5%
34021Toronto North-1%6%
35033Etobicoke South-16%-12%
35125Toronto West-12%-7%
63203Thunder Bay-7%10%
75010North Bay-5%19%
83126Highway 401-10%0%

Notes:

  • Baseline years: 2017-2019.
  • Pre-COVID period: January 1 - March 18; Stay-at-home period: March 19 - May 18; Re-opening period: May 19 - December 31.

Baseline concentrations of fine particulate matter and changes in 2020

Means in baseline years (µg/m3)
IDCity/TownPre-COVID periodStay-at-home periodRe-opening period
12008Windsor Downtown9.06.98.0
29000Hamilton Downtown8.89.08.8
29118Hamilton West8.27.77.8
33003Toronto East8.16.47.1
34021Toronto North8.26.57.2
35033Etobicoke South8.87.67.9
35125Toronto West8.16.37.5
63203Thunder Bay5.84.65.5
75010North Bay4.94.45.0
83126Highway 40110.68.08.8
Changed means in 2020 relative to the baseline years (µg/m3)
IDCity/TownPre-COVID periodStay-at-home periodRe-opening period
12008Windsor Downtown-1.4-1.0-0.8
129000Hamilton Downtown-0.9-1.2-0.6
129118Hamilton West-1.0-0.80.5
133003Toronto East-0.9-0.4-0.4
134021Toronto North-1.2-1.0-0.7
135033Etobicoke South-1.3-1.3-0.3
135125Toronto West-1.2-0.5-0.4
163203Thunder Bay-0.40.40.2
175010North Bay-0.3-0.5-0.2
183126Highway 401-1.6-1.20.4
Changes attributable to the pandemic (%)
IDCity/TownStay-at-home periodRe-opening period
12008Windsor Downtown6%7%
29000Hamilton Downtown-2%4%
329118Hamilton West3%19%
33003Toronto East8%8%
34021Toronto North2%7%
35033Etobicoke South0%12%
335125Toronto West11%11%
363203Thunder Bay17%10%
375010North Bay-5%1%
83126Highway 4016%23%

Notes:

  • Baseline years: 2017-2019.
  • Pre-COVID period: January 1 - March 18; Stay-at-home period: March 19 - May 18; Re-opening period: May 19 - December 31.

Baseline concentrations of ozone and changes in 2020

Means in baseline years (ppb)
IDCity/TownPre-COVID periodStay-at-home periodRe-opening period
12008Windsor Downtown23.632.226.6
29000Hamilton Downtown25.129.923.9
29118Hamilton West25.230.123.0
33003Toronto East24.630.523.2
34021Toronto North24.130.823.0
35033Etobicoke South21.826.921.3
35125Toronto West21.127.720.8
63203Thunder Bay26.931.820.6
75010North Bay28.132.723.9
83126Highway 40118.224.017.4
Changed means in 2020 relative to the baseline years (ppb)
IDCity/TownPre-COVID periodStay-at-home periodRe-opening period
12008Windsor Downtown-0.4-1.61.2
129000Hamilton Downtown0.1-0.81.9
129118Hamilton West-1.4-1.01.6
133003Toronto East0.20.32.0
134021Toronto North0.4-0.22.2
135033Etobicoke South0.10.30.8
135125Toronto West1.20.41.6
163203Thunder Bay-1.7-2.80.0
175010North Bay1.30.3-0.7
183126Highway 401-0.5-0.51.1
Changes attributable to the pandemic (%)
IDCity/TownStay-at-home periodRe-opening period
12008Windsor Downtown-4%6%
29000Hamilton Downtown-3%8%
329118Hamilton West1%13%
33003Toronto East1%8%
34021Toronto North-2%8%
35033Etobicoke South1%3%
335125Toronto West-3%2%
363203Thunder Bay-4%8%
375010North Bay-3%-8%
83126Highway 4010%9%

Notes:

  • Baseline years: 2017-2019.
  • Pre-COVID period: January 1 - March 18; Stay-at-home period: March 19 - May 18; Re-opening period: May 19 - December 31.