How the air can impact your health
The Air Quality Health Index (AQHI) is an indicator of Ontario’s daily air quality based on air pollutants that have adverse effects on human health and the environment.
The AQHI is important to know because it tells you how clean or polluted the air that you breathe is, and what associated health effects you may experience within a few hours or days after breathing polluted air.
In many parts of the country, summer has the worst air quality of any season. When the air forecast indicates a code red air quality day, what does it mean for your health?
“The answer depends on many factors. There’s no simple answer for everyone,” says Dr. Darryl Zeldin, acting clinical director of Environmental Health Sciences at the National Institutes of Health.
He and other NIH-supported researchers have been studying how substances in the air can affect health.
“The combination of high temperatures, few winds and breezes, pollution and airborne particles can brew up an unhealthful mixture in the air, just waiting to enter your lungs. These substances can make it hard to breathe and can sap your energy. If the air quality is especially poor, it may take a few days for your body to recover. If you’re regularly exposed to high levels of unhealthy air, health consequences can linger for months or years,” he says.
One of the most studied pollutants in summertime air is an invisible gas called ozone. It’s created when sunlight triggers a chemical reaction between oxygen-containing molecules and pollution that comes from cars, power plants, factories and other sources.
“Ozone is produced only when you have sunlight and high temperatures or stagnant air, which is why ozone is generally not a problem in winter,” says Dr. Frank Gilliland, an expert in environmental health at the University of Southern California. “High levels of ozone reduce lung function and lead to inflammation, or swelling in the airways. When levels are high enough your chest might hurt when you breathe.”
You may also feel faint, dizzy, short of breath or think you’re having a heart attack. Ozone is a highly reactive molecule that can irritate the lining of your airways and lungs.
“When some people are exposed to just a little bit of ozone, the amount of inflammation in the lungs goes way up, and, as a result, air passages narrow, which makes it harder to breathe,” says Zeldin.
Ozone effects can come on quickly and linger or worsen with time.
“When it’s a bad air day, most people expect their breathing will be affected that day. But, in fact, they often feel effects most strongly a day or two after. We often see an increase in emergency room visits, hospitalizations and use of asthmarelated ‘rescue’ medications and oxygen,” says Dr. David Peden, environmental medicine researcher at the University of North Carolina.
Researchers have also been studying particulates — the fine and course particles that spew from anything that burns fuel, such as cars, industry, wildfires and smoke. Particulates can cause year-round health problems and have been linked to worsening lung problems and increased cardiovascular events such as stroke and heart attack.
Studies by Gilliland and colleagues found children living near busy roadways are more likely to develop asthma and other breathing disorders that substantially affect their lung development.
I had the unfortunate experience of being exposed to poor air quality while vacationing near Roatan, Honduras, in March.
A “poor” air quality red alert was issued there on March 22 due to smoke from burning crops on the mainland combined with air pollution.
When a red alert is issued, it means air pollution concentrations are unhealthy for the general population and going outdoors should be avoided.
The air quality alert stated: “The air has reached a high level of pollution — higher than the maximum limit for 24 hours exposure declared by the World Health Organization.”
I was exposed to this toxic air pollution for seven days. During that time, there was a thick layer of smog hovering over the island that blocked out the sun, sunrises and sunsets.
On Good Friday, I had a severe respiratory attack, shortness of breath, dizzy spells and weakness. When I reached the point of passing out, I was taken to a small clinic and hooked up to an oxygen tank and IV drip. I finally recovered enough to get back to Canada and am now seeking diagnosis and treatment here because I still have symptoms.
I hope no one else ever goes through what I experienced from poor air quality.
NIH research teams have found that genes may affect responses to air pollution. At least one gene protects against the harmful effects of ozone. Unfortunately, 40 per cent of the population lacks a working copy of this helpful gene, so they’re more susceptible to ozone damage.
“Hours after exposure to ozone, they have much more inflammation in the airways compared to those with a working copy of the gene,” says Peden.
Fortunately, there are 286 air quality health index monitors in populated communities throughout Canada.