Week 2: Winds change on measuring air quality
A new air quality index sets out risks to human health in no uncertain terms
BY Jesse McLean
Each week for six weeks, This Magazine’s Jesse McLean delves into the state of air quality in Canada. In this instalment, how a new air quality index is an important (though far from sufficient) step in battling pollution.
Inside the chilled member’s lounge of Toronto’s city hall, the assembled health and environment officials didn’t need to think about the blazing 34°C sun or the threat of a smog advisory. But it was still on their minds. On July 9, supported by the federal and provincial government, the city of Toronto announced the Air Quality Health Index (AQHI)—a $30-million, 18-month pilot project that will let residents know more about the air they breathe. It’s a costly change of wind in the ongoing health battles against air pollution. But, then again, it’s a costly war: lung diseases, which are susceptible to and affected by dirty air, cost Canada’s health-care system more than $15-billion a year.
The current Air Quality Index (AQI) tracks the concentration of pollution in the air and the staff issue daily reports. But can an additional letter really improve how we deal with air pollution? Where the existing system reflects a region’s air quality in relation to provincial standards, AQHI will rate air quality based on its risk to human health—and that might make all the difference. While Canadians are generally well aware of the dangers air pollution carries for those with asthma and pre-existing lung conditions, few outside the research community know the vastness of its impact. For ozone and particulate matter, the two main ingredients of smog, there is no safe level of exposure. On bad-air days, everyone’s affected, says Kenneth Maybee, the national co-chair of the AQHI. “Some people are more sensitive to air pollution, but no one’s safe.”
More than six million Canadians, one in every five, currently suffer from some form of lung disease. But experts say that Canada’s rise in rates—and its possible link to air pollution—is what’s really worth alarm. In the past 20 years, asthma cases among children have quadrupled. Chronic obstructive pulmonary disease (COPD), commonly known as chronic bronchitis and emphysema, is the fourth leading cause of death, and it’s the only one still rising. While almost every other cancer has been on the decline, lung cancer remains the exception. But it’s not just disease rates that are rising: In 2005, Canada recorded 53 smog advisory days, with winter advisories popping up in Ontario and Quebec for the first time ever. Yet Dr. David Yap, an environmental monitor for the province of Ontario, says it’s hard to extrapolate trends from the increase in smog advisories: In 2003, AQI sites started recording particulate matter, increasing the pollutants being monitored, and hence the likelihood of more smog forecasts. “The science is evolving and giving us more information about the impact of air pollution. The awareness is getting better; the air quality isn’t getting worse,” explains Yap. Several Health Canada specialists use a similar reasoning to explain the spikes in asthma and COPD.
But the uncertainty in the science field creates a medical paradox. There’s no doubt that air pollution exacerbates asthma; and research confirms that if people live in areas with a heavily polluted air shed, there’s a higher chance of developing the disease. Yet there’s still great hesitation in associating a real relationship between the two. “That’s always the question,” says Maybee. “How close do you have to be to be 100 percent sure?” The AQHI isn’t waiting to find out. Rather, the new index sidesteps the question and applies what it does know to allow people to moderate their exposure to airborne poisons. Launched last year in the greater Vancouver area and eight other British Columbia communities, the index works as a 10-point scale. As the AQHI value rises, so do the health risks. Behind the concept is what air-quality officials call “self-calibration,” the notion that people know their body’s tolerance, and can use the AQHI’s values to avoid levels that they know will be harmful. Like canaries in a coalmine, people suffering from asthma will feel the effects sooner—and can use the index proactively to prevent asthma attacks. But smog spares no one, and the AQHI prepares each person to adjust her exposure level.
In addition to offering a health-impact index, the AQHI upgrades the current index from reporting just the highest measured pollutant, instead releasing data on area’s ozone, particulate matter and nitrogen oxide levels. “You’re never just breathing in one toxin, you’re breathing in a soup,” says Brian Stocks, the Ontario Lung Association’s air quality manager. By reporting on more than one toxin, the index is providing a measure of more than a general health risk: It will educate people of the effects certain toxins have. For example, research shows that particulate matter is worse for the heart than the lungs. Although larger airborne particles get trapped by the lungs and coughed out, finer pieces of soot, lead and mercury seep into the bloodstream and line themselves along the walls of the heart. “People are generally surprised when I mention that,” says Stocks, who is leading the AQHI in Windsor, Ont. “There’s this assumption that air quality only affects the lungs, and it’s just not true. People with cardiovascular illnesses are incredibly vulnerable to air pollutants.”
Canada is the first country in the world to adopt the health-risk oriented index, and those involved call it a groundbreaking step in preventing deaths triggered by dirty air. But the AQHI is a tool to gauge the problem of air pollution. It’s not a solution. In order to clean the air, the provincial and federal governments need a legislative commitment to reducing emissions. Yet the lack of legislation doesn’t render the index useless. As Maybee argues, change will only come with motion, and that’s what the AQHI offers. “Is what we’re doing the best it could be? Probably not. But the only way for it to be better is for it to be out and active, and we’ll improve it with time.
“Waiting around will just mean more people dying.”
