Researchers at the National Centre for Atmospheric Science (NCAS) have tracked air pollution emissions across North America as part of a six-week study in Toronto with York University.
To build a more complete picture of poor air quality across North America, a team of scientists used satellites, research aircraft, monitoring vehicles and stationary sensors to detect the sources of air pollution. The extensive scope of the study included observing emissions from transport, industry, agriculture, consumer products and wildfires.
Dr Pete Edwards, an atmospheric chemist at NCAS and the University of York, said, “The six-week study is known as The Toronto Halogens, Emissions, Contaminants and Inorganics eXperiment (THE CIX). It’s a ground-site measurement campaign associated with the large-scale program Atmospheric Emissions and Reactions Observed from Megacities to Marine Areas (AEROMMA), which is led by the US National Oceanic and Atmospheric Administration [NOAA].”
Both the THE CIX study and the wider AEROMMA project aim to quantify the emissions that are contributing to poorer air quality, and to understand how these emissions react with one another in the air. Findings from THE CIX and AEROMMA will be shared with state and local environmental officials to inform decisions about the most effective ways to reduce air pollution.
Air pollution is predominantly caused by emissions of nitrogen oxide gases (NOX) and volatile organic compounds (VOCs). These emissions contribute to the formation of ‘ground-level ozone’, a harmful air pollutant that can trigger several health issues.
The sources of these emissions have changed over recent decades. Emissions of NOX and VOCs from vehicles have fallen significantly. However, consumer and industrial volatile chemical products (VCPs) are an increasing source of VOC emissions.
VCPs include a number of everyday products, such as paint, domestic cleaning agents and perfume, and are a large source of VOC emissions in densely populated urban areas. Every product releases a different set of VOCs into the air, leaving behind a kind of chemical fingerprint. These chemicals then interact with one another in the air, sometimes creating new pollutants in a process known as secondary formation.
This summer wildfires have raged across Canada, and recent figures released by the Canadian Interagency Forest Fire Centre reported 909 active wildfires. In June 2023, many cities across North America were engulfed by smoke from the wildfires. The air pollution caused by the smoke led to health officials distributing face masks and advising people to stay indoors.
Preliminary results from the THE CIX study have directly observed negative impacts on Toronto’s air quality caused by wildfire smoke. These results show not only the expected increase in pollutants such as particulate matter but also changes in atmospheric chemistry, such as increases in gas-phase chlorine compounds, which can influence the subsequent formation of secondary pollutants like ozone.
As global temperatures continue to rise, dry weather and heatwaves create conditions in which extreme wildfires are more likely to occur. It is anticipated that the frequency and intensity of wildfires will increase because of global warming. For this reason, NCAS finds it important to understand the impacts of wildfire smoke on air quality.
To find out more about NCAS’s latest developments, click here.