Smoke Signals: How Wildfire Smoke Puts America’s Health at Risk
Warning! Air Quality Alert.
Phones along both coasts, and more recently Maui, have increasingly lit up with health alerts cautioning individuals to take care against hazardous air pollution. A warning once only familiar on the west coast has spread across the mainland US as Canada's raging wildfires exhale their smoke toward Boston, New York City, and Washington DC.
According to a recent study published in The Lancet, at least 33,000 people die every year around the world due to wildfire smoke pollution. Most of these deaths have historically occurred in Central and South America.
Unfortunately for US residents, regular disruption from wildfire smoke appears to be an increasing reality in North America. Wildfires are increasing in intensity and size across the US. Since 2000, wildfires in the US have burned about 7 million acres per year, almost double the amount burned in the 1990s – and equivalent to the entire state of Massachusetts going up in flames. The top four worst wildfire smoke days since the data started being recorded in 2006, occurred in the last three years.
Most attention over the years has been on the dangers of wildfires to infrastructure, the environment, and the economy. But discussions about their threat to public health have also grown in urgency.
The long-term health impacts of wildfire smoke inhalation are still being studied and have traditionally been difficult to ascertain. But a growing body of research has linked wildfire smoke exposure to respiratory morbidity and exacerbated episodes of respiratory risks like asthma. These effects can be particularly dangerous to the most vulnerable populations, including fetuses.
To better understand the risks of wildfire smoke, exposure to cigarette smoke is a helpful comparison.
A Berkley Earth research study compared general air pollution, measured by particulate matter density in the Air Quality Index (AQI), with cigarette smoke exposure. Building on this research, we can estimate the impact of wildfire smoke in terms of cigarette smoke using Stanford University’s ECHO lab data. This combined data set captures pollutant density from wildfire smoke across the contiguous United States, from 2006 through 2020.
Applying this methodology to the US for the most recently available data, the 2020 fire season, produces a bleak picture. At the extreme, residents of Mono County, California (Pop. 13,195), experienced the equivalent of 90 cigarettes in a single week (September 13th, 2020). In 2020, wildfire smoke exposed nearly 25 million people to the equivalent of over 4 cigarettes (over 100 ug/m3) for at least one day.
And the consequences of wildfire smoke pollution extend far beyond the local communities ravaged directly by fires, reaching as far as the East Coast. During that same week in September 2020, 98% of counties within the contiguous United States experienced some level of air pollution due to wildfire smoke.
As wildfires continue to worsen, the health risks associated with wildfire smoke are clearly intensifying. If only we could ban wildfires, like indoor smoking, or walk away like it was avoidable second-hand smoke. While not as simple, the CDC recommends limiting exposure to wildfire smoke as much as possible including wearing N95 masks, staying indoors, and making use of air filters to keep smoke outside.
About the Data
The Stanford Echo Lab’s Daily 10km wildfire smoke PM2.5 data set contains daily smoke particle estimates from January 1, 2006 to December 31, 2020 for the contiguous United States. Estimates are based off machine learning models driven by ground, satellite, and reanalysis data sources.
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The Team
Data Research & Story: Nicole Varela
Design: Anna Davis
Editor: Biniam Gebre