Transcript Climate Change and Air Quality: What We Can Expect

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
• People can
spend a lot
of time close
to pollution
sources
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
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)
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
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
Air pollution makes
asthma worse
Comparison of Illness Estimates for
Toronto from Air Pollution
Year
Published
Data
Period
Annual
Mortality
Annual
Hospitalization
Toronto
Public
Health
2004
1999
1,700
6,000
Health
Canada
2005
1998 to
2000
1,840
----
Ontario
Medical
Association
2005
2005
1,450
3,980
Investigator
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
Smog and Heat Problems
Compounded in Cities
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)
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
1990 levels by 2010
Kyoto Protocol delays doubling CO2 levels
by about 15 years
Temperature Change
Temperature Trend
Source: Environment Canada
Today
Today
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
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?
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
Key Findings - Historical Analysis
• On average (for period 1954 - 2000), 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
Distribution in Mean Annual Mortality
Attributable to Extreme Temperatures and Air
Pollution
Toronto
12
10
78
Montreal
11
13
76
Heat-related
Cold-related
Ottawa
Windsor
9
12
79
11
10
79
0%
20%
40%
60%
Air pollution-related
80%
% of Annual Mortality
100%
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
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
Ontario Air Quality Index (AQI)
Increasing severity of health
effects
AQI Scale
Category
0 - 15
Very Good
16 - 31
Good
32 - 49
Moderate
Smog Alert
50 - 99
100+
Poor
Very Poor
At AQI = 50, OMOE
calls Air Quality
Advisory
Smog Alert Days in Toronto
60
48
Number of Days
50
40
30
20
20
10
10
5
3
1
5
7
18
12
9
14
3
0
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
In 2005, Toronto experienced 48 smog alert days
Diurnal fluctuation in hourly pollutant levels
(Toronto, 1997-2000)
Toronto NO2 (1997-2000)
Toronto O3 (1997-2000)
80
40
35
30
25
20
Days with AQI >=50
Days with AQI <50
15
Concentration (ppb) .
Concentration (ppb) .
45
Days with AQI >=50
70
Days with AQI <50
60
50
40
30
20
10
0
10
01
03
05
07
09
11
13
Hour
15
17
19
21
23
01
03
05
07
09
11
13
Hour
15
17
19
21
23
Diurnal fluctuation in hourly pollutant levels
(Toronto, 1997-2000)
Toronto PM 2.5 (1997-2000)
35
3
Concentration (ug/m )
60
3
Concentration (ug/m )
Toronto PM 10 (1997-2000)
50
40
30
20
Days with AQI >=50
10
Days with AQI <50
0
30
25
20
15
10
Days with AQI >=50
5
Days with AQI <50
0
01
03
05
07
09
11
13
Hour
15
17
19
21
23
01
03
05
07
09
11
13
Hour
15
17
19
21
23
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
Proposed National Air Quality Health
Index (AQHI)
Percent of days at low, moderate, high or
very high health risk levels, 2001
AQHI Level
Low health risk
0-3
Moderate health risk
4-5
High health risk
6-10
Very high health risk
Over 10
Vancouver Hamilton Toronto
Montreal
84
33
36
43
16
46
47
44
1
20
16
13
0
0
1
0
Source: With permission from Dr. Dave Stieb, Health Canada
Heat Alert Days in Toronto
Number of Days
Heat Alerts 2001-05
30
25
20
15
10
5
0
18
Extreme heat alert
Heat alert
2
3
14
6
2001
2002
3
3
0
2
8
2003
2004
2005
Year
In 2005, Toronto has experienced 26 heat alert days of which 18
were in the extreme heat category
Fluctuations in Frequency
of Hot Weather Days in Toronto
(1954 to 2000)
70
3:00 p.m. Temperature ≥ 30°C
60
Hot Weather Types
Frequency of Hot Weather
Events
50
40
30
20
10
0
1954
1959
1964
1969
1974
1979
Year
1984
1989
1994
1999
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