Thousands of residents in communities across parts of California have been advised to stay inside by the Environmental Protection Agency (EPA), as it has recorded pockets of fine particle pollution (known as PM2.5) that have reached “unhealthy” levels, as of Sunday, February 22, at 4.30 a.m. ET.
Which Parts of California Are Experiencing ‘Unhealthy’ Air Quality?
According to the EPA’s AirNow Map—which the environmental agency uses to track, measure, and communicate the quality of air across the United States—the pockets of PM2.5, which have reached “unhealthy” levels, are across two separate parts of California.
One area includes Portola, Cromberg, Sattley, the Sierra Valley, and the Plumas National Forest. The other lies farther south in the eastern Sierra and includes Mammoth Lakes, Mono Lake, Whitmore Hot Springs, and the Silver Divide.
What To Do When the Air Is ‘Unhealthy’
When the EPA issues a warning of “unhealthy” air quality, everyone is advised to minimize their exposure to the polluted air. Those in sensitive groups, which include the elderly, children, and people with existing heart or lung conditions, should be especially careful and avoid intense or lengthy outdoor activities. Everyone else should reduce the intensity and duration of outdoor activities until conditions improve.
This is because PM2.5 is one of the most dangerous types of air pollution, according to the EPA. Particles are so small—less than 2.5 micrometers in diameter, which is smaller than the width of a single strand of human hair—they can be easily inhaled, traveling deep into the lungs and bloodstream. Exposure to PM2.5 can trigger or worsen certain health conditions (like asthma) and cause symptoms like chest tightness, shortness of breath, coughing, and eye, nose, and throat irritation.
The EPA is also warning residents in the affected areas that the polluted outdoor air could impact indoors as well, including in their homes. They should, therefore, avoid burning candles, indoor fires, and wood-stove burners, use air filters or purifiers, and keep windows and doors shut to keep the air as clean as possible.
It also advises people to keep monitoring the AirNow Map and local weather forecasts for further updates, as the air quality and conditions can often change rapidly.
What Is Causing the ‘Unhealthy’ Air Across California
Although the EPA hasn’t yet confirmed what’s causing elevated levels of PM2.5 across parts of California, it can come from a variety of sources. The most common causes of PM2.5 include smoke caused by wildfires or smokestacks, dust rising from unpaved roads, dirt tracks, and construction sites, or emissions entering the atmosphere from vehicles or industrial and power plants.