Recent wildfires in Indonesia and the USA have been making the headlines – how will these deadly and destructive blazes affect us?
In Colorado, a series of fires have been blazing across the state since June 10th resulting in deaths, damage to property and displacement from homes. Over 115,000 acres of the Centenniel State have been affected.
In Arizona, the fire which was sparked by lightning on June 28th captured public hearts after 19 elite fire fighters perished in the blaze.
The fires in both states are still not yet fully under control.
Illegal slash-and-burn forest clearance in Indonesia caused the Pollution Standards Index in Singapore to reach 401 out of 500, the highest level in the country’s history. The public were recommended against any excessive activity and advised to stay indoors.
The most obvious effects of wildfires on humans are direct loss of life and destruction of property. Less direct, and therefore less obvious, is the effect of wildfire air pollution on humans. While research investigating the health effects of urban air pollution is now commonplace, studies looking at wildfires in particular are more scarce.
This is largely due to the unpredictable nature of wildfires, and has consequences for the public perception of the hazard. Importantly, the frequency and magnitude of these events appear to be increasing. A study at the University of California identified a fourfold increase in wildfire occurrences in the Western USA, and a six fold increase in affected areas since the mid 1980s.
What’s Wildfire Smoke Made Of?
Wildfire smoke is a complex mixture of water vapour, carbon dioxide, particulate matter, carbon monoxide, hydrocarbons, nitrogen oxides and trace minerals. Dr Kelly BéruBé, head of the Lung and Particles Research Group at Cardiff University, UK, told Decoded Science that of all wildfire smoke constituents particulate matter is commonly observed to be of most concern. This is due to its well-substantiated links with adverse health effects and large increases during vegetation burning. Dr BéruBé told us that burning vegetation creates the smallest particles, PM2.5 (particles with a diameter of less than 2.5 μm). These particles are small enough to evade our defense mechanisms, and reach far into the lung, to the gaseous exchange region.
While European law states that daily PM10 (particles with a diameter of less than 10 μm) levels should not exceed 50 μg/m3 (with some exceptions), during wildfire episodes, PM10 is often at levels of hundreds of micrograms.