Poor air quality cause for concern at this weekend's Santa Rosa Marathon

Poor air quality is causing concern among participants at the Santa Rosa Marathon this weekend.

Thousands of people are signed up for two days of running: 5k and 10k races on Saturday and a half-marathon and full marathon on Sunday.

"We're all running, we got our t-shirts, whoo hoo!," exclaimed Emi Gao, picking up her race packet at Sports Basement Friday evening.

Gao's excitement was tempered by some unease: about the smoky skies and the thought of being in crowds of thousands.

"I'm keeping my mask on, it's going to be tough while running but I think with COVID and everything I think it's better with the masks," said Gao.

Other runners wondered if their cloth face coverings might mitigate the air pollution.

"We're debating whether to wear masks to filter it out a little bit but I'm not sure if it helps," said Tony Chen of Fremont, running the 5k with his son and other friends.

"We'll take a look at the air quality in the morning and if it's moderate we'll probably run but if it goes to 100 we'll probably drop out."

With 13 major wildfires burning in California, it might be a challenge finding a stretch of days without air pollution.

"These particles can travel a long way and it really depends on how the winds are going," said Dr. John Balmes, a pulmonologist and critical care medicine expert at UCSF.

"Last month, the particles from some of our fires made it all the way to New York City and Philadelphia and fouled the air there."

As uncomfortable as conditions get in the Bay Area, much of the Lake Tahoe area is miserable.

Readings are off the charts due to smoke from the Caldor fire, even ten times worse than Bay Area averages.

But experts note any amount of soot particulate is unhealthy.

It has been known to exacerbate heart and respiratory conditions.

New research shows it makes people more susceptible to COVID-19 by diminishing lung function.

"The particles can make it down to the deep lung, they're small enough to do that," said Balmes.

"They contribute to to lower respiratory tract infections and that leads to an increased risk of COVID infections and poor outcomes."

Friday evening, the Air Quality Index in Santa Rosa was dropping, but slowly, and still registering as "unhealthy for sensitive groups."

"I've done races up here before and I'm super-excited," said Gini Wright of Livermore, picking up her swag bag and modeling her t-shirt.

Like many runners, she has traveled from out-of-town, booked a hotel, and plans to enjoy the post-race street party in downtown Santa Rosa.

"I don't know, it's nice just to be able to get out there and run so we'll see, we'll play it by ear," said Wright.

A mother-daughter team from Petaluma wasn't quite as optimistic.

"I'm worried this will make everybody exhausted and be really bad for our lungs," said Megan Buck.

She and her mom plan to make running a race-day decision.

"If it's just a little bit bad, then I think the run should go on, but if it's hazardous they should cancel it to protect everybody," said Megan.

The advice as always: minimize exertion, reduce smoke exposure, stay indoors with doors and windows closed, recirculate the air and use filtration if possible.