Air quality alert issued in San Diego County as fires burn in Southern California

Multiple wildfires burning north of San Diego County have prompted the National Weather Service to issue an air quality alert for most of the county through Friday evening.

Wildfire smoke may be creating particle pollution through at least Friday at 8 p.m., when the alert is expected to expire for the county's mountains and valleys. This could be an issue for those with respiratory problems like asthma and the elderly, according to NBC 7 meteorologists.

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"If you smell smoke or see ash due to a wildfire, remain indoors with windows and doors closed or seek alternative shelter, if feasible," the NWS said. "Avoid vigorous physical activity and run your air conditioner and/or an air purifier."

Outdoor activities, youth sports impacted in San Diego due to air quality concerns

Some sports clubs in the county were so worried about the air quality that they canceled outdoor practice even before the NWS issued an alert.

Seth Tunick coaches Crusaders Soccer Club. His soccer league has about 1,500 children, ranging from 4-18 years old. He says soccer practice was canceled on Wednesday because the health of his players is top priority.

"Practices are very vigorous," Tunick said. "We don't know what's in the air, and so we have to assume the air quality, and they're running around with a little bit of heat, is going to affect them in a way that would be negative to their health, so we just feel it's best not to let them play."

Air quality experts say the concerning fine particle pollution levels are from the windblown dust of the fires.

"Air quality is a function also of the weather, and what we have are prevailing winds really pulling the pollution down from wildfires into San Diego area," Glory Dolphin Hammes with IQ Air North America said.

The NWS says exposure to those particles can cause serious health problems and increase the risk of respiratory infections. The levels of pollution can vary hour by hour and by location based on the fire behavior and the local weather conditions, according to the agency.

What fires are burning in Southern California?

San Diego crews are helping in firefight against several wildfires to our north, which have collectively scorched more than 100,000 acres.

California Gov. Gavin Newsom issued a state of emergency in Los Angeles, San Bernardino, Orange and Riverside counties due to the fires. He had proclaimed a state of emergency for San Bernardino County for the Line Fire on Monday.

Here's where the fires are burning:

Los Angeles County

The Bridge Fire in Los Angeles and San Bernardino counties is the largest active fire burning in California, according to L.A. County Sheriff Robert Luna. It has prompted evacuation orders for nearby neighborhoods and has destroyed dozens of homes.

The blaze has burned more than 50,000 acres and was 0% contained as of Wednesday at 6:50 p.m.

Orange County

The Airport Fire in Orange County's Trabuco Canyon grew to more than 23,000 acres with 5% containment by Wednesday night.

The blaze, which was first reported on Monday, is now also affecting Riverside County, according to Cal Fire.

Several communities were under evacuation orders and warnings. Two people were injured, while 10 firefighters were treated for minor injuries.

San Bernardino County

The Line Fire burned more than 36,000 acres and was 18% contained as of Wednesday night. It threatened around 65,600 structures in the area.

A man was arrested on suspicion of starting a fire that spread wildly to the Line Fire.

San Diego County

The Roblar Fire that erupted over the weekend has burned 1,000 acres near Camp Pendleton.

The fire was 100% contained as of Wednesday night, according to Cal Fire.