In the early 1900s, the air in a city like New York was so bad you could measure the pollution by just catching the soot from the sky. But we didn’t really know what the soot did to us.
“There wasn't a whole lot of hard evidence other than the fact that when people died who lived in cities, their lungs were often terribly blackened,” says David Stradling, the author of Smokestacks and Progressives, a book on the history of air quality.
As the technology to measure air quality got better, researchers noticed relationships between the pollution in a particular city and the rates of heart and lung disease — and even deaths — of its residents.
Studies on those correlations eventually led to the enactment of the Clean Air Act in 1970, as well as other regulations.
But the science was based on average pollution levels for entire cities, not what specific people were exposed to.
“[Scientists] would use data from large central site monitors that might be the size of a van,” says Darby Jack from the Department of Environmental Health Science at Columbia University’s Mailman School of Public Health, “and might cost you a couple hundred thousand dollars.”
Take a deep breath
Air quality monitors are now smaller and much cheaper. But to track the direct health effects from pollution, you need to know more than just concentration rates.
“You’re missing out on another factor,” observes Steve Chillrud, an environmental chemist at Columbia’s Lamont-Doherty Earth Observatory, “which is how much air you’re breathing into your lungs.”
Partnering with WNYC — and our former health reporter Fred Mogul — Chillrud and Jack came up with the Biking and Breathing project, to measure people’s actual intake, or dosage, of pollution, particularly when they bike every day close to a pollution source, like traffic.
One person who heard WNYC’s call for participants was Jason Aloisio, who was working at the Bronx Zoo and commuting by bike from his home in Bushwick.
For a few days, Jason wore a spandex biometric shirt, a blood pressure cuff, and two air quality monitors that tracked PM 2.5 — particulate matter or dirt, soot or anything in the air that’s 2.5 micrometers or less.
The shirt tracked how much Jason’s chest expanded as he breathed in to estimate the volume of air he was inhaling. Along with data from the air monitors, the researchers could calculate Jason’s dose of pollution at different points along his route.
Jack and Chillrud’s team found that one of the worst spots on Jason’s commute was the middle of the Ed Koch Queensboro Bridge.
First, there is all the exhaust from the idling traffic on the bridge — then, add to that, Jason’s deeper breathing as he bikes up the hill to the middle of the bridge, which exacerbates the effects of that pollution.
Oddly enough, because it he get to look over the East River, Manhattan and Queens, the bridge was actually Jason’s favorite spot on his route. “You know if New York City was ever getting me down,” says Jason “stopping on the top and seeing that beautiful view on the top of Queensboro Bridge, especially sunrise, was always kind of a moment.”
How bad is bad?
The EPA doesn’t have standards for how much particulate matter is okay to you should breathe in; they only set limits on pollution for the air around you.
But if we assumed an average person breathed in the maximum amount allowed by the EPA, the cyclists from the Columbia study breathed in much more pollution during their commutes: about 2.5 times above this modified EPA limit.
Over the course of their entire day though, which they generally spent in cleaner air indoors, the cyclists inhaled less than the EPA threshold.
This summer, the researchers are hoping to recruit over 150 cyclists to figure out whether there are health effects from those short spikes in particulate matter dosage. They hypothesize that a cyclists’ blood pressure and heart rate may be affected — though not so much as to nullify the benefits of biking and exercise.