Thousands of residents across a part of California, including communities in San Bernardino, Orange, and Riverside counties, have received an air quality alert from the National Weather Service (NWS) and have been advised to stay inside through Sunday, as particle pollution in the atmosphere has reached “harmful levels.” 

What’s Causing Poor Air Quality in California?

According to the NWS, the elevated level of particle pollution across an area in California is due to windblown dust.

Particle pollution can also come from smokestacks and wildfires, as well as from emissions from power and industrial plants and vehicles.

Who Will Be Affected By Poor Air Quality?

The NWS air quality alert—which has been in place since Saturday morning and is expected to expire by Sunday evening—warns that everyone in the affected areas could be impacted by poor air quality, especially those in sensitive groups, such as the elderly, children, and those with existing heart and lung conditions. 

The affected area includes the San Bernardino and Riverside County Valleys (the Inland Empire), the Riverside County Mountains and Santa Ana Mountains and foothills, the Coachella Valley, the San Gorgonio Pass near Banning, and inland Orange County.

Cities impacted include Riverside, San Bernardino, Ontario, Moreno Valley, Fontana, Rancho Cucamonga, Corona, Idyllwild‑Pine Cove, Indio, Palm Springs, Cathedral City, Palm Desert, Palm Desert Country, La Quinta, Coachella, Santa Ana, Anaheim, Garden Grove, Irvine, Orange, Fullerton, and Mission Viejo.

What Should People In Areas With Poor Air Quality Do?

All members of the public should take steps to avoid exposure to polluted air by either avoiding or limiting the intensity and duration of outdoor physical activities. 

They should also try to reduce the amount of dust in the air by slowing down while driving on unpaved or dirt roads and stabilizing any loose soil.

This is because the particles of pollution can often be so small—sometimes less than 2.5 micrometers in size, which is smaller than the width of a strand of hair—they can “get deep into the lungs and cause serious health problems such as asthma attacks, heart and lung disease symptoms, and increased risk of lung infections,” according to the NWS. They can also trigger symptoms that range from coughing and nose, eye, and throat irritation to chest tightness and shortness of breath. 

Alongside avoiding air outdoors and reducing dust in the atmosphere, residents in affected areas should also try to keep the air inside as clean as possible, including in their homes. 

The NWS advises them to keep windows and doors closed and, if possible, use an air conditioner, purifier, or filter to help circulate clean air around the house. They shouldn’t use house fans or swamp coolers, as they can bring outdoor air inside, and they should avoid burning candles, incense, wood-burners, and indoor fires until conditions improve. 

Residents should monitor local forecasts and the Environmental Protection Agency’s (EPA) AirNow Map for updates, as air quality can often change quickly.Â