How Air Quality Affects Health
A new report (August 2008) by the Canadian Medical Association estimates that in 2008, up to 21,000 Canadians will die from air pollution — specifically, particulate
matter and ground-level ozone. Most of these deaths will be from chronic disease, rather than acute episodes.
The CMA report predicts that, in B.C., there will be 306 premature deaths due to air pollution in 2008, increased emergency-room visits, hospital admissions and doctor’s-office visits. Air pollution
is expected to cause about two and a half million minor illnesses in 2008, in this province alone.
In the past, scientists thought that respiratory disease was the major outcome of exposure to air pollution. However, scientists such as the American College of Cardiology have now found that cardiovascular
morbidity and mortality is a significant problem, too. To find out more, visit the CMA site: What
Is Air Pollution Costing You?
Indoor Air Quality
Indoor air can also carry pollutants that cause or aggravate illness. For more information, see Indoor
Air Quality (BC HealthFiles)
and Indoor Air Quality (Environment Canada).
At current levels, particulate matter is the most serious kind of local air pollution in the province. It poses more danger to human health than ground-level ozone (in smog), and other common air pollutants like carbon monoxide.
From our lungs' point of view, bigger particulates are less harmful. Because of their weight, the larger particulate matter — between 10 and 2.5 microns in diameter (PM10) — settles
to the ground quickly. If we do inhale it, this particulate matter collects in our nose and throat. Then our body eliminates it through such processes as sneezing and coughing.
In contrast, particulate matter that's less than 2.5 microns in diameter (PM2.5) can remain in the air for days to weeks. It can penetrate deep into our lungs, collecting
in tiny air sacs (alveoli) where oxygen enters the bloodstream. Health problems begin when the body starts to react to these foreign invaders. Another danger is that PM2.5 can contain a number
of potentially harmful substances, such as cancer-causing chemicals.
Coughing and wheezing are two of the mild problems associated with inhaling PM2.5. However, this type of air pollution can also cause or worsen serious illnesses such as asthma, heart disease,
chronic bronchitis, emphysema and pneumonia. Exposure to PM2.5 is associated with a significant rise in the number of premature deaths from respiratory
and heart disease. It's also linked with more emergency room visits, hospitalization, and time off work and school. Long-term exposure in pregnant women can cause premature births and low birth weights.
Senior citizens, infants, and people who already have lung, heart and other illnesses (such as diabetes) are the most vulnerable.
However, healthy adults and children can be affected, too.
PM2.5 and asthma are a bad mix. PM2.5 can increase the number of asthma attacks, and make them more severe. Over 1.2 million Canadians suffer from this condition, and asthma is the most common cause of medical emergencies in children.
A 2002-3 BC Lung Association study of air quality in the Lower Fraser Valley found that even low amounts of PM2.5 in the air can harm our health. In fact, the study pointed out that a safe
level of PM2.5 (below which there are no health impacts) has not been found. As PM2.5 increases, so do the health problems. Long-term exposure to PM2.5 is an added health hazard.
Low concentrations of ground-level ozone can irritate the eyes, nose and throat. Ozone can also irritate the lung airways, and make them red and swollen (inflammation). As the amount of ground-level
ozone increases, it can trigger more serious illnesses, including coughing, asthma, bronchitis, chest pain, breathing difficulties during outdoor exercise and greater susceptibility to
lung illnesses like pneumonia. Prolonged exposure can damage lung tissue, cause premature aging of the lungs and contribute to chronic lung disease.
As with particular matter and other forms of air pollution, children, the elderly and people with impaired lung function are considered to be most at risk. However, even healthy people and athletes who are active outdoors can be affected when ozone levels are high.
Carbon monoxide is an invisible gas that is a fast-acting poison. When carbon monoxide is inhaled, it gets into the bloodstream. Then it attaches itself to the oxygen-carrying red cells and stops them
working. Without oxygen the body cannot function properly.
It doesn’t take much carbon monoxide to make people sick. At low amounts, carbon monoxide can make healthy people feel tired, and cause chest pain in people with heart disease. Higher concentrations can cause impaired vision and coordination, headaches, dizziness, confusion, nausea — and flu-like symptoms that clear up after leaving the polluted area. Carbon monoxide is fatal at very high concentrations.
Other Air Pollutants
Other pollutants, such as sulphur dioxide (SO2), nitrogen oxides (NOx), mercury, polycyclic aromatic
hydrocarbons (PAHs), benzene, and dioxins and furans can cause a wide range of health effects. These
include cancer, lowered immunity, disorders of the nervous system, and interference with child development. Dioxins and furans are among the most toxic chemicals in the world.