The first study into the global impact of wildfire-related pollution and deaths comprehensively links short term exposure to wildfire-related fine particulate matters (PM 2.5 ) in the air and all-cause, respiratory and cardiovascular mortalities across cities and regions around the globe.
The landmark study, published today in The Lancet Planetary Health, looked at data of more than 65.6 million deaths, from all causes, in 749 cities in 43 countries and regions from January 1, 2000 to December 31, 2016 – cross referencing to daily concentrations of wildfire PM 2.5 concentrations.
The research from an international team, led by Professor Yuming Guo and Dr Shanshan Li, from the Monash University’s School of Public Health and Preventive Medicine in Melbourne, Australia, found that over 33500 deaths occurred each year directly attributable to wildfire pollution, across the 749 cities in the study. According to the data, countries with the most deaths related to wildfire smoke include Japan, with over 7000 annual deaths in 47 cities, Mexico, over 3000 in 10 cities, China, over 1200 in 15 cities, South Africa, over 5200 in 52 cities, Thailand, almost 5300 in 62 cities, and the USA, with almost 3200 annual deaths in 210 cites relating to airborne wildfire PM 2.5 .
In recent years, there has been widespread wildfire devastation of wildfires - from the 45 million acres scorched during Australia’s 2019-2020 fire season, the more than 1.2 million hectares burnt across California since the start of 2019, to the record amount of carbon dioxide released from more than 190 wildfires across Siberia, which now make up more than the rest of the world’s wildfires combined.
According to Professor Guo, wildfires can have direct impacts on health such as injury and mental health consequences. “However the pollution from wildfire smoke can spread as far as 1000 kilometres away and the risk of wildfires is projected to increase as climate change worsens,” he said.
One of the pollutants within wildfires smoke that is the most concerning is fine particulate matter, PM 2.5 , as particles in this size range enter into the lungs, across the alveoli in the lung walls and into the circulation. Wildfire PM 2. is more toxic than that from urban fires because of its chemical composition, smaller particle size and associated high temperatures, the authors state in the paper.
The mortality data was obtained from the Multi-City Multi-Country (MCC) Collaborative Study and estimations for the daily concentrations of PM 2.5 were modelled by machine learning, outputs of chemical transport model, ground monitors’ measurements of PM 2.5 , and weather data.
The authors conclude that: “policy makers and public health professionals should raise awareness of wildfire pollution to guide prompt public responses and take actions to reduce exposure. Effective wildland management policies and practices should be implemented to manage vegetation and mitigate climate change as far as possible.”
DOI: https://doi.org/10.1016/S2542-5196(21)00173-X
Link: http://www.thelancet.com/journals/lanplh/article/S2542-5196(21)00173-X
Average annual deaths and attributable fraction due to exposure to wildfire-related PM 2·5 in 749 cities of 43 countries/regions
Country/region
Cities
numbers
All-cause mortality
Cardiovascular mortality
Respiratory mortality
Number
Fraction (%)
Argentina
3
478
0.77
NA
Australia
483
0.88
Brazil
18
1,610
0.70
Canada
26
440
0.33
132
35
0.32
Chile
4
190
0.43
China
15
1,289
0.66
527
0.67
166
0.65
Colombia
5
585
0.97
164
60
0.95
Costa Rica
1
16
0.94
0.92
Czech Republic
43
0.14
21
0.13
2
Ecuador
210
0.98
58
25
0.99
Estonia
13
0.17
Finland
11
0.15
France
127
0.12
8
0.11
Germany
12
172
Greece
95
44
10
0.34
Guatemala
238
3.04
Iran
41
14
0.28
Ireland
6
36
0.09
0.08
Italy
254
0.30
Japan
47
7,062
0.63
1,990
0.61
1,045
Kuwait
0.37
0.36
Mexico
3,078
1.72
778
1.69
300
1.77
Moldova
0.27
Netherlands
Norway
Panama
0.38
Paraguay
64
2.09
2.10
2.19
Peru
1,454
1.61
Philippines
436
0.79
140
0.80
48
0.78
Portugal
38
0.26
Puerto Rico
9
Romania
142
0.35
South Africa
52
5,278
790
1.00
740
1.10
South Korea
733
0.53
168
51
0.52
Spain
234
0.19
74
27
0.18
Sweden
0.10
Switzerland
19
7
Taiwan
348
0.58
75
0.57
Thailand
62
4,291
2.32
809
2.43
558
2.44
UK
70
188
USA
3,193
978
310
Uruguay
156
0.51
Vietnam
266
63
1.04
22
Note: Attributable numbers of deaths were calculated using the pooled global-level risk estimates.
The Lancet Planetary Health
Meta-analysis
People
Mortality risk attributable to wildfire-related PM2·5 pollution: a global time series study in 749 locations
8-Sep-2021
N?A