Thousands of Americans are at risk of breathing in dangerous toxins on both the East and West Coasts, with officials warning that local air quality could cause 'serious health effects.'
The US Environmental Protection Agency (EPA) reported on Wednesday that air quality levels had reached 'unhealthy' levels in portions of California and Oregon, including over the city of Los Angeles, home to nearly four million people.
The increased leaves are due to little to no wind and high atmospheric pressure trapping pollution near ground level. In parts of Hollywood, Air Quality Index (AQI) readings reached 170, classified as unhealthy for all residents.
Air quality maps showed sharply elevated levels of PM2.5, microscopic particles composed of toxic compounds or heavy metals that are small enough to penetrate the lungs, creating hazardous conditions, especially for those with ailments such as asthma.
These particles come from automobile exhaust, factory fumes, and burning wood, which, when inhaled, can inflame the human respiratory system.
A large swath of Oregon, including the La Pine and the Deschutes National Forest, has seen AQI levels rise above 160 on Wednesday morning, fueled by polluted air being unable to move out of the area.
The EPA's AirNow monitoring system also highlighted large areas of Georgia and South Carolina, including cities like Savannah and Valdosta, that are seeing air quality deemed 'unhealthy for sensitive groups.'
Air quality levels are measured on a scale from 0 to 500: good (0–50) carries little risk, moderate (51–100) may affect sensitive individuals, unhealthy for sensitive groups (101–150) poses increased risk, and unhealthy (151–200) impacts everyone, limiting outdoor activity.
According to the live air quality-tracking website IQAir, Los Angeles is currently the most polluted city in the US.
IQAir warned that PM2.5 levels in the city were 5.2 times higher than the World Health Organization's recommended safe limit on Wednesday.
Health experts have cautioned that prolonged exposure can trigger respiratory problems, aggravate cases of asthma, strain the heart, and contribute to long-term lung damage.
Authorities in all affected states have urged residents to minimize strenuous outdoor activity and monitor local air quality forecasts on days when levels reach 'unhealthy' levels for the general public.
On Tuesday, the Oregon Department of Environmental Quality extended an air quality advisory for the region around Lake County and southern Deschutes County, explaining that stagnant air was trapping smoke and other pollutants near the ground.
Stagnant air means the air around you is barely moving, like it's stuck under a lid, so pollution, smoke, car fumes, and other particles can't blow away or mix higher up in the atmosphere, causing them to build up near the ground where we breathe.
This often happens during calm, high-pressure weather with light winds and a temperature inversion, where warmer air sits on top of colder air near the surface, trapping everything below it and making the air quality worse over time.
The alert is expected to last through Thursday, and the public has been advised to avoid using wood-burning stoves and other devices that produce indoor smoke.
'Use certified High Efficiency Particulate Air (HEPA) filters in indoor heating, ventilation, cooling and air purification systems,' Oregon DEQ said in a statement.
The National Weather Service (NWS) has also warned that widespread dense fog alerts are spreading the risk of poor air even further along the West Coast.
NWS revealed that the massive belt of 'radiation fog' has returned over a stretch of more than 200miles of Central California, from the San Joaquin Valley to Sacramento.
While it is unrelated to nuclear radiation and generally should not endanger human health, officials have warned that radiation fog can cause extreme risks for driver visibility and can severely impact air quality by trapping local pollutants close to the ground.
NWS has also issued a 'very high transportation risk' for drivers throughout this fog belt, with the alert reaching Level 5, the highest grade for motorist safety, meaning cars won't be able to see more than 200feet in front of them.
Both a dense fog and stagnant air alert has been issued in southern Oregon and western Idaho, affecting major cities like Boise, home to more than 200,000 people.
'Persons with respiratory illness should follow their physician's advice for dealing with high levels of air pollution during periods of stagnant air,' NWS said in a statement.
