Air pollution in Hamilton similar to ‘smoking one cigarette a week’: study


Published July 14, 2023 at 2:04 pm

The leading researcher of a Hamilton air quality study has compared the harmful effects of air pollution found in the city to smoking one cigarette a week.

The impact for Hamiltonians most exposed to the pollutants comes particularly from the chemical and air pollutant benzo[a]pyrene, considered carcinogenic to humans, according to a new study.

“I know it’s not a perfect analogy but it is one that I think people can understand kind of give a sense of the magnitude of this potential health risk,” said Matthew Adams, assistant professor from the University of Toronto’s Department of Geography, Geomatics and Environment, during a public Zoom webinar on July 11. Adams has lived in Hamilton since 2011.

The study found elevated amounts of benzo[a]pyrene in all locations of Hamilton except rural areas. Its effects are intensified with sunlight. In the short term, it can irritate the skin or eyes.

“Benzo[a]pyrene is maybe a bit more than I would expect it elevated across all of the locations in urban areas of our city,” Adams said.

Adams told webinar attendees that the new air monitoring initiative collected air quality data across every ward in Hamilton using passive air samplers at 67 sites. These air samplers gathered 30-day samples, four times per year during every season. Air pollutants sampled include nitrogen dioxide, nitric oxide and nitrogen oxides, ozone, sulphur dioxide, benzene, and polycyclic aromatic hydrocarbons (PAHs) including benzo[a]pyrene. (PAHs are chemicals derived from coal, crude oil and gas, or from burning certain materials). 

According to the study, Hamilton has some of the highest emissions of the benzo[a]pyrene pollutants in Ontario, especially the closer you are to the industrial core. “Unfortunately, what we see is across almost the entire city of Hamilton, really all of the urban areas … benzo[a]pyrene is above Ontario’s Ambient Air Quality Criteria.”

Rural residents advised to pay attention to air quality index

On the brighter side, the study found Hamilton isn’t exceeding the 2025 Canadian Ambient Air Quality Standards for the transportation-related air pollutant nitrogen dioxide, Adams said. The standards focus on health and environmental-based outdoor air quality.

“We do see more of the pollution in downtown. This is not really surprising,” he explained during the public webinar. “But it’s not just related to that industrial core, it’s really related to what’s going on with traffic in the lower city paired with the industrial core. … As we move further into the rural community, the concentrations just drop off.”

Ozone concentrations were typically lower in urban areas where there’s higher nitrogen dioxide. They’re highest in the rural regions, which he said are likely underestimated. Ozone is linked to cardiorespiratory illnesses and disease. “From kind of a health perspective, you know ozone is an infrequent issue, but when it does become an issue it really spikes up.  So I think we need to think about ozone-related air pollution really in our rural communities because it may actually be underestimating what they’re exposed to but the air monitors … represent urban exposure to ozone quite well but not so much rural exposure to ozone.”

He recommended people even in rural areas to pay attention to Air Quality Health Index alerts because having higher ozone levels will mean a higher risk. “Just because you live in a rural area, you may not be thinking about air pollution but ozone is one of the contributors to the Air Quality Health Index,” he said. “Ozone can have great short-term health effects because we often see big peaks in the summer … tenfold increases during the day.”

The industrial-related pollutant sulphur dioxide showed up across most of the city in “generally low concentrations.” But Adams noted that the study found “elevated concentrations” around the industrial areas, in the lower city and along Beach Boulevard.

“(Sulphur dioxide) used to be more prevalent across Ontario before coal-fired power plants were removed, but we’ll see it’s still an issue here in Hamilton.”

Sulphur dioxide forms when fuel that contains sulphur, such as coal, oil or diesel, is burned.

“So we still need to be paying attention to this pollutant within really anything below the escarpment,” Adams said, adding that people could see levels that could be up to 25 times higher than expected during the summer. “It might be really high one day and it’ll drop down and be low again for a week or two. So we need to keep paying attention to (sulphur dioxide) long term.” 

Large number of vehicles a pollution problem: researcher

The researchers said the project is unique as it uses many passive air monitors across the city and it’s designed to include the community in the process, including discussing the data with the team. For the study, at least one passive air monitor was located in every ward in the city. The project also monitored the air quality through all four seasons.

Although the city has seen industrial reductions of pollutants, a large number of vehicles have offset the improvements, Adams said. 

City of Hamilton staff from the Air Quality and Climate Change Office spearheaded the project, teaming up with Adams and Environment Hamilton.

For the study, filters were hung on street poles for up to two months and taken back to the laboratory for analysis to determine how much  pollutants were in the air. “So we’re able to capture what air pollution looks like across space near and around where people are living,” Adams said.

Public meeting ‘Zoombombed’

Some City officials, researchers and about 100 participants attended the July 11 Zoom meeting. The webinar was halted midway for less than a minute when an unknown person posted a pornographic video clip. The presentation continued without any other disruptions after the person was kicked out of the system.

Ian Borsuk, interim executive director of Environment Hamilton, said the “Zoombombing” is a “pretty common and absolutely frustrating problem” based on his experience and the experience of other organizations in Hamilton and elsewhere that he spoke with.

“The issue is also why most governments don’t use Zoom but instead use other services like Webex — but for a group like us, Zoom is the most affordable option — but of course because it’s the most affordable and most popular option, trolls can easily find ways to disrupt meetings,” he said in an email to “What pissed me off the most was that this was our final webinar and we didn’t have any interruptions on the previous (three meetings).”

Click here to view the edited webinar detailing the findings.


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