Millions of Americans are being told to stay indoors as dangerous air pollution reaches unhealthy levels across parts of multiple states on Friday.
The National Weather Service has issued multiple air quality alerts covering major population centers of Colorado and California as ozone smog, fine particle pollution and windblown dust threaten to worsen respiratory conditions.
The alerts affect communities stretching from Colorado’s Front Range Urban Corridor to Southern California’s Coachella Valley and parts of East Los Angeles.
Breathing in ozone can significantly damage human lungs, along with triggering breathing difficulties, asthma attacks and other health problems, particularly among children, older adults and people with existing lung disease.
In Colorado, hot temperatures and stagnant weather conditions are allowing ozone pollution to build near the ground.
Officials in California are battling separate pollution events driven by harmful fine particles and wind-blown dust.
Residents in affected areas are being urged to reduce strenuous outdoor activity and take steps to keep indoor air clean.
The alerts remain in effect Friday, with some areas expected to remain under warnings through Saturday morning.
The alerts affect communities stretching from Colorado’s Front Range Urban Corridor to Southern California’s Coachella Valley and parts of East Los Angeles.
The Colorado Department of Public Health and Environment issued an Ozone Action Day Alert for the Front Range Urban Corridor, covering Douglas, Jefferson, Denver, western Arapahoe, western Adams, Broomfield, Boulder, Larimer and Weld counties.
The alert began Thursday afternoon and remains in effect until 4pm local time on Friday, according to the NWS alert.
Officials warned that hot, stagnant weather will allow ozone levels to climb into the ‘Unhealthy for Sensitive Groups’ category.
Ground-level ozone, often referred to as smog, forms when sunlight reacts with pollutants emitted by vehicles, industrial facilities and other sources.
Residents were asked to reduce driving whenever possible in an effort to limit additional pollution.
The warning affects millions of residents living along the busy Interstate 25 corridor from the Denver metro area north toward Fort Collins.
Meanwhile, Southern California is facing two distinct air-quality threats.
The South Coast Air Quality Management District issued an alert for the Coachella Valley due to harmful levels of particle pollution generated by windblown dust.
The alert covers communities including Indio, Palm Springs, Cathedral City, Palm Desert, La Quinta and Coachella and remains in effect until 11am local time on Saturday.
Officials warned that particle pollution can penetrate deep into the lungs and contribute to serious health issues, including asthma attacks, worsening heart and lung disease symptoms and an increased risk of respiratory infections.
Another air quality alert was issued for Boyle Heights and East Los Angeles because of elevated levels of fine particle pollution.
The warning remains active until Friday afternoon.
Fine particle pollution, known as PM2.5, consists of microscopic particles that are small enough to travel deep into the respiratory system and, in some cases, enter the bloodstream.
According to officials, exposure can increase the risk of heart attacks, bronchitis, asthma flare-ups and breathing difficulties.
While anyone can experience health impacts from poor air quality, officials said certain groups face significantly greater risks.
These include people with heart or lung disease, older adults, pregnant women, children and those who spend long periods outdoors.
Residents in affected areas are being advised to keep windows and doors closed, run air conditioning systems or air purifiers when possible and avoid activities that could further worsen indoor air quality.
Officials also recommend avoiding fireplaces, candles, incense, grilling and gasoline-powered lawn equipment during periods of poor air quality.
Air quality can change rapidly depending on weather conditions, wind patterns and local emissions, meaning pollution levels may vary considerably even within the same city.
Forecasters said residents should continue monitoring local air quality reports and limit outdoor exertion when pollution levels rise into unhealthy categories.
