Smog, smog alerts and human health
Health effects of smog
How big a health issue is smog? Green Ontario claims that
smog kills 1800 Ontarians each year.1
Health Canada analyzed air pollution in relation to deaths in
eight Canadian cities, and, (considering both short- and
long-term effects), concluded that air pollution causes 5,900
deaths each year in these cities alone.2
On smoggy days, emergency room visits, hospital admissions and
medication use all go up. As usual, the most vulnerable are
children, the elderly, and those with underlying lung and heart
problems. Pets, with their relatively fast respiration and small
body size, suffer too.
What about asthma? It is controversial whether outdoor air
pollution actually causes asthma.3
While asthma is often worse when air pollution is high, it is
not clear whether this is due to the general increase in
pollutant levels or to specific allergies to ozone, nitrogen
oxides or particulate.4
What is in it?
The dirty yellow smog that we see consists mainly of
ground-level ozone and fine particulate matter (PM). It is most
common when sunlight and hot stagnant air trap pollutants in the
lower atmosphere.5
Smog levels usually peak mid-afternoon, when the sun is at
maximum intensity.
Most smog is due to human activity; though some is also caused
by forest fires, volcano dust, etc.6
Despite Ontario's Anti-Smog Action Plan, it's likely to get
worse with time. Climate change is expected to bring hotter
temperatures, more forest fires, worse air pollution, and more
smog, in future years.
Keeping track of it
Ontario's Ministry of the Environment (MOE) has an extensive
website that shows "air quality indices".7
The MOE issues smog advisories when they expect smog levels to
be elevated over a relatively large area, and to persist. In
2005, there were 15 smog advisories (for a total of 53 days); in
2007, 13 such advisories (for a total of 39 days). In last
year's wet summer, there were only 8 advisories (for a total of
17 days) and in 2009 (to the end of June) only two advisories
(for 2 days total) had been issued.8
The MOE reports air quality indices (AQI) every hour, every day
of the year.9
The AQI is based on six air pollutants that adversely affect
human health: ozone, PM, nitrogen dioxide, sulfur dioxide, total
reduced sulfur compounds and carbon monoxide. Forecasts on the
site are pretty generic, but easy to understand - air quality is
categorized as "good", "moderate" and "poor".
If you want more detail, MOE provides hourly air concentrations
for five pollutants at various "stations" (i.e., cities and
towns) around the province.10
There are also useful links that explain the nature, source and
effects of each pollutant.
What is being done about it
Ontario has an anti-smog action plan: details at
http://www.greenontario.org/strategy/smog.html.
Most of the plan involves using less energy (especially for
transportation), burning it cleanly, and promoting renewables.
Closing Ontario's coal-fired power plants should help a lot,
although more than half of our smog blows in from the US.
The best way to tackle smog is to design our cities,
transportation systems, and energy use in such a way that it
reduces air pollution. Smog is not an isolated problem; it is an
indicator of poor urban and economic development.11
In addition, the MOE is encouraging municipalities to take a
stronger role in fighting smog, and publishes a municipal guide
for smog alert response.12
Individual and community action on smog issues looks about the
same as action on climate change and energy conservation. Small
wonder. Coal and petroleum are the biggest contributors to smog,
and energy use is one of the easiest targets for individual
action. Trees and other green plants also help clean the air, so
if you have a street tree nearby, look after it!
Six suggestions if you or a loved one is vulnerable13
- Pay attention to smog alerts.
- Chemicals: don't use aerosol sprays or oil-based paints and
volatile chemicals that add to poor air quality both indoors and
outdoors; don't smoke.
- Exercise: During smog alerts, vulnerable people should avoid
strenuous outdoor exercise, especially in late afternoon when
ground-level ozone peaks. (Glad I'm a morning person).
- Stay inside: when there is a smog alert, as susceptible
individuals may suffer difficulty breathing as well as
irritation of the eyes and/or throat.
- If you have asthma, increase monitoring lung capacity during
smog alerts and adjust medication doses accordingly.
- Complain to your politicians. Make them take smog seriously.
1
http://www.greenontario.org/strategy/smog.html
2 Environment Canada. Health
issues - air pollution is linked to varying degress to a number
of health concerns…
http://www.ec.gc.ca/cleanair-airpur/Health_Concerns-WSC8A1FE65-1_En.htm
3 The Global Initiative for Asthma - Global strategy for asthma
management and prevention (2008 update):1-92 at 6. GINA
guidelines Available at
http://www.ginasthma.org/Guidelineitem.asp??l1=2&l2=1&intId=1561
4 GINA at 56
5 Environment Canada. Smog.
http://www.ec.gc.ca/cleanair-airpur/Smog-WS13D0EDAA-1_En.htm.
Winter smog, due mainly to PM, can occur when stagnant air
results in a buildup of air pollutants, e.g., through increased
wood burning and use of vehicles
6 Environment Canada. Revised mortality estimates due to air
pollution in Canada.
http://www.ec.gc.ca/cleanair-airpur/Revised_Mortality_Estimates_Due_to_Air_Pollution-WS2BFC7599-1_En.htm
7 Ontario Ministry of the Environment - Smog alert site -
http://www.airqualityontario.com/alerts/alert.cfm
8 MOE - How many smog advisories were issued in previous years?
http://www.airqualityontario.com/press/smog_advisories.cfm
9
http://www.airqualityontario.com/alerts/alert.cfm
10 Ontario MOE - Pollutant Concentrations -
http://www.airqualityontario.com/history/summary.cfm
11
http://www.greenontario.org/strategy/smog.html
12 Smog Alert Response - A
municipal guide to action. 2005:1-101. Available at
http://www.ene.gov.on.ca/envision/gp/5093e.pdf
13 Ontario Ministry of the Environment - Spare the air actions.
http://www.airqualityontario.com/science/spareair.cfm; Abelsohn
A, Stieb D, Sanborn MD, Weir E. Identifying and managing adverse
environmental health effects: 2. Outdoor air pollution. CMAJ
2002;166(9):1161-7
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