Current air regulations treat all PM2.5 air pollution as equally dangerous. But recent research suggests particulate matter in wildfire smoke is significantly more toxic than it is in typical outdoor ambient air pollution. Wildfire smoke may be far more dangerous than current air quality indexes indicate.
Wildfire Smoke: Why PM2.5 Is So Important
Tiny particulate matter (PM2.5) is one of the most dangerous and well studied air pollutants. PM2.5 is so tiny the particulates can enter deep into your bloodstream and damage your organs. Studies have shown that PM2.5 from wildfire smoke can exacerbate a range of health problems including respiratory and cardiovascular issues.
It is estimated PM2.5 is responsible for 4.2 million deaths globally each year. These PM2.5 particles are 2.5 microns or smaller in size. To get an idea of how small these particles are, see the graphic below in comparison to a strain of hair.
Due to the danger PM2.5 poses to humans, PM2.5 levels are often used to gauge the severity of air pollution. For example, the air quality is considered worse with 50 micrograms of PM2.5 compared to 40 micrograms. In other words, focus is typically put on the amount of PM2.5 in the air, rather than the exact composition of the PM2.5 and source of the particles.
But recent research shows perhaps more focus should be put on the source of the PM2.5 pollution, not just the quantity.
Fine Particles From Wildfire Smoke More Dangerous Than Other Sources
The study shows that fine particles in wildfire smoke are significantly more dangerous to one’s health than fine particles from other sources in equal quantities. After isolating just the wildfire-specific PM2.5, the study found respiratory-related hospitalizations increased between 1.3 to 10%. Contrary, non-wildfire PM2.5 was associated with 0.67 to 1.3% increases in respiratory-related hospitalizations.
Why PM2.5 From Wildfires Is More Toxic Than Ambient PM2.5
The composition of PM2.5 from wildfire smoke is quite different from ambient urban PM2.5. Wildfire PM2.5 is largely comprised of carbon (5–20% elemental carbon and over 50% organic carbon). Due to wildfire smoke having more polar organic compounds, wildfire smoke generates more free radicals which can result in increased inflammation and oxidative stress in the body.
Take Away: Not All PM2.5 Is The Same
Current air quality standards do not distinguish between the source of PM2.5. Since research shows that PM2.5 from different sources have different risks, lower PM2.5 levels may not always mean healthier air. More research should be done in this domain to help better assess the dangers of PM2.5 from different sources and update air quality guidelines accordingly to better account for these dangers.