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Air Quality in Ontario 2015 Report
The Air Quality in Ontario Report, the 45th in a series, summarizes the state of ambient air quality in 2015 and 10-year trends for key airborne pollutants affecting Ontario’s air quality.
2015 Highlights
Overall, air quality in Ontario has improved significantly over the past 10 years due to substantial decrease in harmful pollutants such as nitrogen dioxide, sulphur dioxide and carbon monoxide that are emitted by vehicles and industry.
There has also been a significant decrease in fine particulate matter which is emitted directly into the atmosphere as a by-product of fuel combustion or formed indirectly in the atmosphere through a series of complex chemical reactions. Fine particulate matter includes aerosols, smoke, fumes, dust, fly ash and pollen, and can have various negative health effects, especially on the respiratory system.
The continued decrease in these pollutants is due in part to Ontario’s air quality initiatives such as:
- The phase-out of coal-fired generating stations
- Emissions trading regulations, (O. Reg. 397/01 and O. Reg. 194/05)
- Emissions controls at Ontario smelters
- Drive Clean testing of vehicle emissions
The following table shows the decreasing trend for airborne pollutant concentrations from 2006-2015 and emissions from 2006-2015:
| Pollutant | Concentrations |
|---|---|
| Nitrogen dioxide | ↓ 32% |
| Sulphur dioxide | ↓ 48% |
| Carbon monoxide | ↓ 53% |
| Fine particulate matter | ↓ 25% |
| Pollutant | Emissions |
|---|---|
| Nitrogen oxides | ↓ 38% |
| Sulphur dioxide | ↓ 44% |
| Carbon monoxide | ↓ 32% |
| Fine particulate matter | ↓ 11% |
Ozone trends
Ozone is a pollutant formed when nitrogen oxides and volatile organic compounds (a group of pollutants from sources such as transportation, industrial activities, and use of solvents) react in the presence of sunlight. This means that formation and transport of ozone is very dependent on weather conditions and air pollutant concentrations.
Overall, annual ozone concentrations have increased three per cent over the past 10 years. Ozone concentrations can vary due to the season: winter ozone concentrations have increased by nine per cent while summer ozone concentrations have decreased by four per cent.
The winter increases are due mainly to rising global background concentrations of ozone. The summer increases are a result of reductions in emissions of pollutants such as nitrogen oxides and volatile organic compounds within Ontario and the U.S.
The following table shows a decreasing trend for six volatile organic compounds from 2005-2014, based on data collected at eight ambient air monitoring stations:
| VOC | Concentrations |
|---|---|
| 1,3 Butadiene | ↓ 62% |
| Benzene | ↓ 42% |
| Toluene | ↓ 64% |
| Ethylbenzene | ↓ 79% |
| m-, p-xylene | ↓ 85% |
| o-xylene | ↓ 84% |
Introduction
This annual report, the 45th in a series, summarizes the state of ambient air quality in Ontario during 2015 and examines 10-year trends. It reports on the measured levels of six common air pollutants: ground-level ozone (O3), fine particulate matter (PM2.5), nitrogen dioxide (NO2), carbon monoxide (CO), sulphur dioxide (SO2) and total reduced sulphur (TRS) compounds, and how Ontario is performing compared to the province’s Ambient Air Quality Criteria (AAQC). This report also provides an overview and implementation of the new Air Quality Health Index (AQHI) and Air Quality Alert programs in Ontario, plus the monitoring of select volatile organic compounds (VOCs) in the province. Annual statistics, as well as 10-year trends of ambient air quality data are provided in the attached Appendix.
| Contaminant | 1-hour AAQC | 8-hour AAQC | 24-hour AAQC | Annual AAQC |
|---|---|---|---|---|
| O3 | 80 ppb | n/a | n/a | n/a |
| PM2.5 | n/a | n/a | 28 μg/m3(1) | n/a |
| NO2 | 200 ppb | n/a | 100 ppb | n/a |
| SO2 | 250 ppb | n/a | 100 ppb | 20 ppb |
| CO | 30 ppm | 13 ppm | n/a | n/a |
(1) Reference level based on Canadian Ambient Air Quality Standard (CAAQS).
Ontario continues to benefit from one of the most comprehensive air monitoring systems in North America, comprised of 39 monitoring sites across the province that undergo regularly scheduled maintenance and strict data quality assurance and quality control (QA/QC) procedures to ensure a high standard of data quality and data completeness. The data, which are collected continuously at these sites, are used to determine the current state of ambient air quality and are reported every hour on the Air Quality Ontario website.