Clean Air Hamilton has issued another mostly favourable report card on air quality in Hamilton. The report is drawn from air sampling conducted from a network of air quality monitoring stations across Hamilton. This network consists of provincially-owned air quality monitoring stations, air monitors owned and operated by members of the Hamilton Air Monitoring Network (HAMN), as well as two air-pointer monitors owned and operated by the City of Hamilton. The report shows significant declines in most pollutants since the 1990s as a result of increasingly stringent vehicle emission standards, and better abatement practices with industry.
Some of the highlights include:
Total Suspended Particulate (TSP)
• The two Industry Stations in Hamilton show a decreasing trend of TSP and all stations (two City & two Industry) are below the annual objectives.
Inhalable Particulate Matter (PM10)
• PM10 makes up 40-50% of TSP in Hamilton and is primarily derived from vehicle exhaust emissions, industrial stack and fugitive dusts (non-stack), and the finer fraction of re-entrained road dust;• The two Industry and two City stations located in Hamilton show decreasing trends since 2018.
Respirable Particulate Matter (PM2.5)
• PM2.5 is derived from residential and transportation sectors. In Hamilton, there would also be some industrial contributions. Another significant portion of PM2.5 is regionally generated emissions that can travel hundreds of kilometres via wind from where they originated. These transboundary flows play a significant role in Ontario’s air quality and according to the Hamilton Airshed Modelling System (HAMS), transboundary emissions in Hamilton for PM2.5 amounted to approximately 91%;
• The Hamilton Mountain and Hamilton Downtown air quality stations show a decreasing trend of PM2.5, whereas the Hamilton West station shows an increase between 2019 to 2020;
• MECP data shows that Hamilton Downtown continues to have the highest concentrations of PM2.5 relative to other municipalities across Ontario that have air quality stations measuring PM2.5.
• The number of hourly exceedances greater than 50 parts per billion (ppb) increased in 2020 in comparison to 2019 for the Hamilton Downtown, Hamilton Mountain, and Hamilton West monitoring stations, but is below 2018 levels;
• Hamilton’s 30-year ozone trend is comparable to many other municipalities in Ontario. Recent 2020 concentrations show Hamilton having one of the lowest concentrations of O3, compared to other jurisdictions.
Sulphur Dioxide (SO2)
• Concentrations since 2016 have shown a slight increase in the industrial area, with
the annual average being recorded above the provincial Annual Objective;
• Conversely, SO2 monitored at the Hamilton Downtown station has been decreasing since 2018 and was below the annual objective in 2020;
• While SO2 concentrations in downtown Hamilton are achieving the provincial Annual Objectives, the average concentrations are higher compared to other Ontario municipalities.
Nitrogen Dioxide (NO2)
• Sectors producing the majority of NO2 emissions are transportation and industry. The level of vehicle use across Hamilton has increased slightly during the past decade, however overall NO2 levels have decreased most likely due to improved vehicle engine technologies;
• NO2 concentrations have shown a significant decrease since 1999. In recent years, the Hamilton Downtown air monitoring station recorded a steep decrease for 2019 to 2020. There is an increasing trend observed in industrial areas since 2018;
• NO2 concentrations in Hamilton are higher when compared to other Ontario municipalities.
• Benzene is a carcinogenic (cancer-causing) volatile organic compound (VOC) that is emitted from some operations within the steel industry, specifically coke ovens and coke oven by-product plant operations. Gasoline can also be up to 5% benzene. Vapours containing benzene may be released during pumping at gasoline stations. Transboundary benzene levels amount to 70% according to HAMS;
• Concentrations of benzene for all monitoring stations (Industry 1, 2, 3, and Hamilton Downtown) remain above the Annual Objective.
• BaP, also a carcinogen, is emitted when carbon-based fuels such as coke, oil,
The report noted that there is significant amount of transboundary (air emission sources outside of Hamilton) contributions to local airshed pollution concentrations in Hamilton. For example, and as noted above, HAMS estimated that transboundary sources contribute approximately 90% of PM2.5, 70% of Benzene, and 29% of BaP concentrations locally across Hamilton. However, local industrial, on-road and off-road transportation emissions continue to contribute to localized air pollution and downwind airsheds as well.
In 2020, Hamilton did not experience any Special Air Quality Statements or Smog and Air Health Advisory instances2. For more information on current and historical air quality concentrations in Hamilton and across Ontario see: http://www.airqualityontario.com/.
The air quality picture in Hamilton will improve likely further, with the announcement by ArcelorMittal Dofasco of plans to transition away from operating blast furnaces to electric arc steelmaking.