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Transit Indoor Air Quality

Posted in Air Quality, on September 29, 2017

As we’ve already seen this month on the blog, as we head back to school and work our indoor air quality can be effecting how well we are able to perform our jobs or how our children do their schoolwork.

But good indoor air quality isn’t just limited to the buildings that we live and work in - a worrisome study released in spring 2017 looked at the indoor air quality of riders on the Toronto Transit Commission, or TTC. What they found wasn’t exactly the best news for your lungs. This study found that TTC subway stations and trains had the greatest levels of indoor air quality pollution when compared to Canada’s two other major transit systems in Montreal and Vancouver.

Initiated by Health Canada and run using researchers from the University of Toronto and McGill University, students using the transit system wore backpacks containing portable instruments to measure tiny particles in the indoor air quality. They then used the subway, traveling a single route continuously, or getting out and taking measurements at certain stations. Indoor air quality measurements often look for different things than outdoor air quality measurements, but the particles these researchers were hunting for can affect both indoor air quality and outdoor air quality. In this study, they were looking for airborne particles that are smaller than 0.00025 centimeters, or PM2.5.

These atmospheric particulates are most often emitted during combustion - such as cars, trains, or other from other machines run using gasoline. These particles are particularly dangerous to human health because their small size makes them easy to inhale, where they become lodged in the lungs. Long-term exposure to PM2.5 in your indoor air quality is suspected to cause cancer and other lung-related diseases. Researchers found that the particulate matter in TTC platforms and trains’ indoor air quality measured at an average of 100 micrograms per cubic meter - Health Canada recommends that safe indoor air quality has as “low as possible” levels of PM2.5. 

This level of indoor air quality pollution is comparable to a normal day in Beijing, China, a country with notoriously poor air quality. In the TTC system, these high levels of indoor air quality pollutants were found to be caused by high concentrations of metal particles; in the Montreal and Vancouver transit systems, poor indoor air quality was found to be caused by rubber tires, concrete rails, and other pollutants.

The good news about this is that this study is already seven years old, and major repairs and improvements have been made to the TTC’s system and indoor air quality. New trains on Line 1 have modern HVAC systems that help improve indoor air quality inside subway cars, and station improvements have aimed to increase air flow and station cleanliness. Despite the scary numbers about indoor air quality on the TTC, your risk as a commuter is generally low - for the average commuter spending about an hour underground a day, your exposure to indoor air quality pollutants only rises by about 20% overall, making it a better health experience than sitting on the 401 during rush hour.

If you have concerns about your indoor air quality, please get in touch with us at SafeAir for a professional assessment!

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