BILLINGS, Mont. — Huge gaps between air quality sensors in the western U.S. have created blind spots in the warning system for wildfire smoke plumes sweeping North America this summer, amid growing concern over potential health impacts to millions of people exposed to the pollution.
Government programs to alert the public when smoke pollution becomes unhealthy rely on about 950 permanent monitoring stations and dozens of mobile units deployed around significant fires.
Those stations are heavily concentrated around major cities on the West Coast and east of the Mississippi River — a patchwork leaves some people unable to determine local risks from smoke, including in rural areas where air quality can quickly degrade when fires ignite nearby. The problem persists far beyond fire lines because wildfire smoke travels for thousands of miles and loses its tell-tale odor yet remains a danger to public health.
The monitoring gaps underscore what officials and public health experts say is a glaring shortage of resources for a type of pollution growing worse as climate change brings increasingly long and destructive wildfire seasons to the U.S. West, southern Europe, and eastern Russia.
Microscopic particles in wildfire smoke can cause breathing issues and more severe problems for people with chronic health conditions. Long-term effects remain under study, but some researchers estimate chronic smoke exposure causes about 20,000 premature deaths a year in the U.S.
“It’s a very frustrating place to be where we have recurring health emergencies without sufficient means of responding to them,” said Sarah Coefield, an air quality specialist for the city of Missoula, Montana. “You can be in your office just breathing smoke and thinking you’re OK because you’re inside, but you’re not.”
Perched along the Clark Fork River with about 75,000 people, Missoula is surrounded by mountains and has become notorious as a smoke trap. All across the region are similar mountain valleys, many without pollution monitors, and smoke conditions can vary significantly from one valley to the next. Montana has 19 permanent monitoring stations. That’s about one for every 7,700 square miles (20,000 square kilometers) or an area almost as big as New Jersey. New Jersey has 30. Data on air quality is particularly sparse in eastern Montana, where smoke from a 266-square-mile (690-square-kilometer) fire on the Northern Cheyenne Indian Reservation got so bad this month that officials closed a health clinic when air filters couldn’t keep up with the pollution.