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Out of the Haze: Air Quality Hazards from Wildfires

Bill Jones

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Nov 8, 2019

The Amazon rainforest in South America covers more than 2 million square miles (roughly the size of Texas), with approximately 60% located in Brazil. While wildfires in the Amazon are not uncommon, the number of wildfires jumped greatly this year, causing massive destruction across the region and spurring deforestation. By the end of the summer, it’s estimated that 3,500 square miles of the Amazon rainforest had burned. A thick wildfire-fueled smoke spread over a very large area—the city of Sao Paulo, Brazil, nearly 1,000 miles from the fires, was plunged into a daytime darkness.

How Harmful is Wildfire Smoke?

Beyond the obvious threat to life and property in the burn zone, smoke and ash can produce tremendous amount of air pollution leading to very poor air quality lasting for days or weeks. This threatens the health of thousands of people—often hundreds of miles from where the wildfires originate. Pollutants such as particulate matter, carbon monoxide, nitrogen dioxide, and volatile organic compounds are often emitted. Indirect pollutants stemming from wildfires also include fine particulate matter and ozone.

Another factor to consider is that wildfires, particularly if they impact populated areas, can burn much more than trees and brush. Cars, tires, gasoline, paints—anything in a developed area can burn—and many of these items will release very toxic pollutants into the atmosphere.

Assessing Full Scope of Air Quality Hazard

The focus of any wildland firefighting effort should always be preventing the spread of fire to populated areas. However, even if the flames are kept away from a populated area, it’s likely that surrounding areas will be significantly impacted by the air pollution caused from a nearby wildfire. Consequently, in the event of a wildfire burning near a populated area, it’s important for local governments and other organizations to be able to quickly and accurately ascertain air pollution levels. They can then advise the local population as to any health risks and what measures they can take to protect themselves.

Without proper preparation, it can be extremely difficult to quickly determine air pollution levels while a wildland fire is underway. The best approach is to have an established air quality monitoring network around an area so that, when a wildfire does develop, air pollution levels can be instantly understood. Where to place these monitors is very important as improperly sited monitors can provide misleading data which can cause officials to make poorly informed—and incorrect—decisions.

By assessing both local climatological conditions as well as local topography, meteorologists and air quality scientists can assess a situation to identify the best locations for monitors, ultimately providing local officials with the accurate information they need to advise people of air quality issues and how best to protect themselves.