Study details hazards from wildfire smoke
A new study found that tiny particles of soot from wildfires, which millions of Californians are breathing in, are up to 10times as harmful to human respiratory health as particulate pollution from other sources.
Choking smoke from record wildfires blanketed Northern California last summer and fall. It turned Bay Area skies an otherworldly orange, raising health concerns over a hazard that is increasing as temperatures continue to climb and poorly managed forests burn out of control each year across the West.
With this winter being extraordinarily dry, the chances of another big wildfire year are high. But the flames may not pose the biggest danger to the most people: A new study published Friday found that tiny particles of soot from wildfires, which millions of Californians are breathing in, are up to 10 times as harmful to human respiratory health as particulate pollution from other sources such as car exhaust, factories or power plants.
“We’ve been really successful in reducing air pollution across the country by improving standards for automobiles, trucks and power plants,” said Tom Corringham, a research economist who studies climate and atmospheric science at the Scripps Institution of Oceanography at UC-San Diego. “The trend has been a decrease in air pollution. But these wildfires are getting worse.”
Corringham and his fellow researchers studied the number of people admitted to hospitals with respiratory problems daily from 1999 to 2012 in Southern California. They compared it to data from fires, Santa Ana winds and smoke plumes from San Diego to Santa Barbara.
They found that when air pollution of tiny particles called PM 2.5 — for particulate matter 2.5 microns or smaller, so small that 30 of them can line up along the width of a human hair — increased modestly, the number of people admitted to hospitals for respiratory ailments like asthma increased by 1% on average. But when PM 2.5 levels
from wildfire smoke went up by the same amount, or 10 micrograms per cubic meter, there was a 10% increase in those hospital admissions.
The tiny particles can penetrate deep into people’s lungs, enter the bloodstream and increase the risk of heart attacks, strokes and other serious health issues.
Last year, 4.2 million acres — an area 13 times the size of the city of Los Angeles — burned in California, the most in modern times. Fires from the Santa Cruz Mountains to the Southern Sierra sent enormous plumes of smoke over the state’s largest cities, and as far away as the East Coast. On Sept. 9, smoke mixed with the marine layer, turning Bay Area skies an apocalyptic orange.
The Bay Area Air Quality Management District called 30 “Spare the Air” days in a row from August 18 to September 16. Soot levels nearly as bad blanketed the Bay Area during the Camp Fire in 2018 and Wine Country fires in 2017. In the Sierra, the Sacramento Valley and parts of Southern California, air quality was even worse least year, reaching 10 to 15 times the federal health standard.
A study by Stanford researchers concluded that the fires last fall caused 1,200 excess deaths and 4,800 extra emergency room visits in California, mostly among people 65 and older with pre-existing conditions like respiratory problems, diabetes and heart disease.
More is on the way. Wildfire risk is expected to be high this summer due to the unusually dry winter. Last fall, state and federal officials signed an agreement to double the rate of thinning forests that have grown unnaturally thick due to generations of fire suppression. Gov. Gavin Newsom added $1 billion to California’s state budget this year for increased forest management, fuel breaks, fire inspections and fire crews.