LOS ANGELES - For weeks, millions of Californians were smothered by smoke from a record explosion of wildfires burning through grass, shrubs, conifer forests, houses and mobile home parks. Eyes watered. Lungs burned. Skies glowed orange.
People suffered sore throats, headaches and chest pains. Many cloistered themselves indoors as pollution spiked to "hazardous" levels, or worse, on the Air Quality Index.
While most people were not threatened directly by fires burning up and down the West Coast, smoke transported health dangers to nearly every corner of the state. State air quality officials are aware of no precedent for so many people breathing such high levels of wildfire smoke for so long.
Even as air quality begins to improve, many remain worried about long-term health impacts.
"Frankly, we don't really know about the long-term effects of wildfire smoke because community exposures haven't been long term before," said Dr. John Balmes, a professor of medicine at UC San Francisco and a member of the California Air Resources Board.
Health experts are fairly certain that such levels of wildfire smoke did significant harm in the immediate term by aggravating chronic lung and heart conditions, triggering asthma attacks, strokes and heart attacks. Scientists also suspect that heavy smoke has lowered people's defenses against the coronavirus, and put them at greater risk of severe symptoms.
But the question of lasting health damage remains hazier. Though the link between chronic exposure to the fine-particle pollution in urban smog and long-term health problems is well-established thanks to thousands of studies and decades of research, there has been relatively little research when it comes to wildfire smoke.
Understanding the long-term consequences is critical, scientists said, because wildfire smoke is a growing health hazard, responsible for an increasing share of the fine-particle pollution across the Western U.S. And with climate change warming and drying out landscapes, helping to fuel bigger, more intense fires, you can expect more smoky days in the future.
In just the last month, fires have generated both the highest readings and most widespread unhealthy levels of fine-particle pollution since continuous monitoring began in the late 1990s, California air quality officials said.