Fires burning across California and Colorado are pumping out smoke that would be bad enough on its own, but might also worsen coronavirus symptoms, doctors warned Thursday.

Three doctors in California say residents should be aware that wildfire smoke worsens respiratory symptoms and could lead to increased ER visits for asthma and other respiratory issues.

Smoke particles from the fires, which spread for hundreds of miles, damage the lungs, said Dr. Stephanie Christenson, a University of California San Francisco assistant professor of medicine.

The particles, 20 to 30 times smaller than the diameter of a hair follicle, “can get in and lodge deeply in the lungs and cause inflammation,” Christensen told a briefing sponsored by UCSF.

“And that is also what we were worried about in Covid-19, whereas people get more severe disease, the inflammation in their lungs can overwhelm the system, and potentially cause really severe issues,” she said.

It’s not certain smoke worsens coronavirus symptoms, she said, but it probably does.

ER visits may soar

Emergency rooms can expect an increase in the number of patients showing up with respiratory symptoms, said Dr. Jahan Fahimi, medical director of the UCSF Emergency Department.

“During times of poor air quality, emergency departments will oftentimes be on the receiving end of patients with respiratory complaints and so we do expect that in places where the wildfires are particularly raging bad, that those ERs will likely see an uptick in the number of patients presenting to the ER,” Fahimi said.

This is where things get tricky when dealing with a pandemic and wildfires.

People are being told the outdoors is safer for averting coronavirus infections. “That certainly is true,” Fahimi said.

“However, when the air quality is this bad, outdoor poses a whole new risk with respect to the wildfire exposure. All the more reason to shelter in place and stay at home.”

Cotton masks not adequate

And then there is the issue of masks.

“Important to remind people that the cloth face coverings that people are wearing with regard to Covid-19 do not protect you – by in large, do not protect you – from wildfire smoke exposure,” said Dr. John Balmes, a UCSF professor of medicine in the divisions of occupational and environmental medicine and pulmonary and critical care.

That doesn’t mean people should nix the cotton masks altogether. “If you can’t get either a surgical mask or an N95, wear the cloth mask, because the most important thing right now is to protect others from transmission of the virus,” Balmes said.

Plus, said Fahimi, people infected with Covid-19 “who are irritated by wildfire smoke may cough and sneeze and spread that virus, so ever more important for everyone to wear to wear masks.”

And what about the firefighters working on the front lines, in close quarters, sleeping in tents and eating together?

“It’s an issue,” Balmes said. “The US Forest Service has been concerned about this for months.”

Crews with the US Forest Service are trying to camp separately and socially distance. When firefighters aren’t on the front lines, they are wearing masks, he said.

Compounding the issues — CalFire often utilizes prisoners on the fire lines.

“Prisoners have been particularly hard hit with SARS-CoV-2 infection,” Balmes said. This year at a fire training camp for prisoners, “I think about half of the people being trained came down with the SARS-CoV-2 infection,” he said.

“It’s a big problem and we have to really support our firefighters. They are working really hard in very dangerous conditions and are really at risk for both Covid-19 and the effects of wildfire smoke,” he said.