1. Concerns for Health from Smog and Heat
Presentation to Smog Workshop
for Ontario Medical Officers of Health
Convened by Clean Air Partnership and
Ontario Medical Association
Dr. David McKeown
February 2006

2. People can spend a lot of time close to pollution sources

3. Health Effects of Air Pollution
More and longer lasting respiratory symptoms
Reduced lung function
More bronchitis and asthma attacks
More emergency room visits
More lung cancer and heart attacks
More hospitalizations & early deaths

4. Burden of Illness Estimates – How Many People Are Affected?
Is a form of risk assessment
Applies risk coefficients from existing epidemiological studies worldwide
Uses community-specific data on daily pollution levels
Uses community-specific data on adverse health outcomes such as hospitalizations and mortality (e.g. for respiratory and cardiac causes)

5. Air Pollution Burden of Illness – Toronto (2004)
1,700 premature deaths/year
6,000 hospitalizations/year
Would likely not have occurred when they did without exposure to air pollution
Preventable
Increases severity or frequency of common medical conditions and illnesses
Created comprehensive agenda for provincial action to improve air quality

6. Pyramid of Health Effects Toronto Annual Estimates for Inhalable Particulates (PM10)
Premature mortality (acute)
177
Cardiovascular hospitalization
421
Respiratory hospitalizations
597
Adult chronic bronchitis
1,186
Emergency room visits
5,981
Bronchitis in children
11,997
Asthma symptom days
71,930

7. Air pollution makes asthma worse

8. Comparison of Illness Estimates for Toronto from Air Pollution

9. Air Quality Benefits Assessment Tool (AQBAT)
Computer simulation tool developed by Health Canada
Estimates human health benefits or impacts from changes in air quality
Pollutants – CO, NO2, O3, SO2, PM2.5, PM10
Health Endpoints
– Mortality (acute and chronic)
– Acute respiratory symptom days
– Chronic bronchitis
– Cancer
– Cardiac and respiration hospitalizations
– Emergency room visits
– Restricted activity days

10. Smog and Heat Problems Compounded in Cities
- shows canyon effect
- cycling close to vehicle exhaust
- what happens when you ‘subtract’ vehicles from the city?
- Atlanta during 17 days of Atlanta summer Olympic games, improved availability of public transit meant big reduction in peak downtown traffic and better air quality
- during this time, there was a 40% reduction in asthma episodes in children (peak levels important)

11. Urban Populations at Increased Risk
Vehicles and people are in close proximity
Canyon effect of buildings traps pollutants
Urban heat island effect
Roads contribute to heat retention in cities
Local emissions compound transboundary pollution
Elevated exposures during commuting (whether walking, cycling, waiting streetside for transit, or inside a vehicle in stagnant traffic)
- people in cities often closer to the source of vehicle emissions than in rural settings; therefore personal exposures higher, including infiltration of traffic-related pollutants to inside homes along major traffic routes
- dense urban centres typically several degrees warmer that rural periphery
- roads themselves contribute significantly to heat retention (heat sink that gives off heat at night as well, slowing nighttime cooling)
- roads occupy a greater proportion of surface area of landmass in cities than in rural setting, in which natural landscapes contribute to cooling
- many studies demonstrate elevated pollution levels inside vehicles during commuting in dense traffic corridors
- cycling - inhalation rates may be 6 times higher than when sedentary; if cycling close to heavy traffic, get increased inhalation of pollutants
- mouth breathing with heavy exertion - by-passes filtration capacity of nose, resulting in higher pollutant exposure

12. Climate Change is Happening
Green House gas (GHG) emissions increasing in Canada
Mean global temperature increased about 0.6C in last 100 years (1C in Canada)
Mean global temperatures expected to increase about 3 C this century
Kyoto Protocol - reduce GHG by 6% below levels by 2010
Kyoto Protocol delays doubling CO2 levels by about 15 years

13. Temperature Trend Today Today Temperature Change
- temperatures have been relatively stable in pre-industrial times
- have increased about 1 degree C in the last century, yet associated with more extreme weather events already
- more frequent tornados, more severe droughts, more flash floods and hail storms
- Intergovernmental Panel on Climate Change has estimated that inflation-adjusted cost of storms around the world has increased more than 20-fold over the past 30 years
- Insurance Bureau of Canada reports cost of disaster losses in Canada rose by 65% between the late 1980s and early 1990s
Today
Source: Environment Canada

14. Health Concerns with Extreme Heat
Death occurs when core body temperature rises 5 C
Seniors and infants at increased risk due to reduced capacity for temperature regulation
Contributory factors include high blood pressure, obesity, physical inactivity, medication use
about 10,000 Americans died due to oppressive heat in summer 1980
about 11,000 Europeans died from heat in summer 2003

15. Major Study Undertaken (Toronto Public Health, Environment Canada and Health Canada)
What are the combined effects of weather and air pollution?
What can we expect in the future?
How can we improve the heat warning system?

16. Key Findings - Historical Analysis
Heat-related mortality significantly higher for seniors and those with cardiovascular illness than others
On those days with extreme heat, average daily mortality about twice as high as for comfortable days

17. Key Findings - Historical Analysis
On average (for period ), of the acute deaths each year in Toronto:
120 were heat-related
105 cold-related
822 were air pollution-related
About 20% mortality associated with extreme temperature and 80% with air pollution

18. Distribution in Mean Annual Mortality Attributable to Extreme Temperatures and Air Pollution

19. Key Findings - Projections for Future
Based on average of five climate change scenarios and current air emissions remaining constant, the study projects:
heat-related mortality will double by 2050 and triple by 2080
air-pollution related mortality will increase by 20% in 2050 and 25% in 2080, largely because of increased ozone levels from global warming
Global warming will make air pollution problems worse

20. Public Warning Systems
Air Quality Index (AQI) - smog advisory issued by OMOE when AQI predicted to be 50 or greater (regional and persistent)
Heat Health Alert system- alerts issued by Toronto Public Health (other Canadian cities exploring similar system)
Extreme Heat Alert - greater than 90% chance of heat-related excess mortality
Heat Alert - greater than 65% chance of heat-related excess mortality
- AQI - purpose is to let people know air pollution levels throughout the days, and predicts when air quality is expected to be particularly poor (issues a smog alert or advisory)
- was improved by OMOE in August 2002 when it added respirable particles (PM2.5) to the AQI; expect an increase in the number of poor air quality days
- purpose of smog advisories is to warn people when air pollution levels are so poor that everyone should protect themselves, such as by avoiding strenuous activity outdoors
- people with respiratory and cardiac problems are at increased risk from the effects of air pollution.
- these people make up a significant portion of the population; prevalence of childhood asthma is high (about 12% of children under 14) and has greatly increased over the last 2 decades
- heat alert system modeled on that of other major U.S cities such as Chicago
- gives advance warning of when heat-related mortality is expected
-enables people to protect vulnerable populations (seniors, homeless)
- in Toronto, all heat alerts also occurred on Smog Alert days, however there were more smog alert days than heat alerts
- in 2001, 6 heat alert days; 3 extreme heat alerts; 20 smog alerts

21. Ontario Air Quality Index (AQI)
AQI Scale
Category
0 - 15
Very Good
Good
Increasing severity of health effects
Moderate
Smog Alert
Poor
At AQI = 50, OMOE
calls Air Quality Advisory
100+
Very Poor

22. Smog Alert Days in Toronto
In 2005, Toronto experienced 48 smog alert days

23. Diurnal fluctuation in hourly pollutant levels (Toronto, 1997-2000)

24. Diurnal fluctuation in hourly pollutant levels (Toronto, 1997-2000)

25. Guidance Regarding Physical Activity and Air Pollution
Be physically active outdoors
Reduce intensity of outdoor activity at AQI levels that trigger symptoms or when AQI exceeds 50
To reduce exposure, plan strenuous activity such as running or jogging before morning rush hour and in low traffic areas

26. Proposed National Air Quality Health Index (AQHI)
Percent of days at low, moderate, high or very high health risk levels, 2001
AQHI Level
Vancouver
Hamilton
Toronto
Montreal
Low health risk
0-3 84 33 36 43
Moderate health risk
4-5 16 46 47 44
High health risk
6-10 1 20 13
Very high health risk
Over 10
Source: With permission from Dr. Dave Stieb, Health Canada

27. Heat Alert Days in Toronto
In 2005, Toronto has experienced 26 heat alert days of which 18 were in the extreme heat category

28. Fluctuations in Frequency of Hot Weather Days in Toronto (1954 to 2000)

30. Conclusions Air pollution continues to pose considerable health risk
Global warming makes air pollution and its impacts worse
Public health sector can catalyze and support reduction in emissions of air pollutants and greenhouse gases
Heat and smog alert warning systems help individuals take personal precautions