More people around the world are exposed to wildfire smoke that has the potential to harm human health, and their numbers are growing, new research finds.
More than 2 billion people are exposed to at least one day of potentially health-impacting wildfire smoke each year, a figure that has grown by almost 7% in the past decade, according to a study led by Australian scientists.
Moreover, each person in the world had on average 9.9 days of exposure per year, a 2% increase over 10 years, the researchers found. They also said exposure levels in poor countries were about four times higher than in high-income countries.
The recent Canadian wildfires that spread smoke across North America highlighted the increase in severity and frequency of wildfires due to climate change.
“The exposure to air pollution caused by landscape fire smoke traveling hundreds and sometimes even thousands of kilometers can affect much larger populations, and cause much larger public health risks,” said Yuming Guo from Monash University’s School of Population Health and Preventive Medicine.
“Mapping and tracking the population exposure to landscape fire-sourced air pollution are essential for monitoring and managing its health impacts," Guo said in a university news release. This will also help prevention efforts and strengthen arguments for mitigation of climate change, he added.
Those health impacts can include increased death and disease, with a global worsening of heart and lung conditions and mental health.
For the study, the researchers used a machine learning approach to estimate the global daily air pollution from all fires from 2000 to 2019. They also looked at global landscape fire-sourced ozone.
The study defined landscape fires as any fire burning in natural and cultural landscapes, including wildfires, and planned or controlled fires.
Exposure levels of PM2.5 — fine particle air pollution — were particularly high in Central Africa, Southeast Asia, South America and Siberia.
The findings were published online Sept. 20 in the journal Nature.