Millions of Californians are breathing harmful air as hundreds of wildfires are happening in the state, especially in the northern and central parts of California.

With these wildfires, it deteriorated the air quality over large swaths when residents are already at a high risk of pulmonary disease because of the COVID-19 pandemic.

"Most, if not all, major urban areas in California have been affected by poor air over the past week," the California Air Resources Board said in a report.

Fine particles than can reach deep into the lungs was recorded at highest level of PM2.5 in Santa Cruz County and Monterey Bay region.

Environmental Protection Agency's Air Quality Index said that about one-third of the Golden State was deemed to have an air quality unhealthy for all members of the general public.

The assessment was as of 2:30 p.m., Monday. It also included highly populated areas like the San Francisco Bay Area, Fresno, and the capital city of Sacramento.

Monday afternoon's rating of 548 west of San Jose was three times higher than the closest global figure, according to purpleair.com

"The concentration of the tiny particles (PM2.5) in the Bay Area is roughly five times the daily average limit set by the EPA. It's worse in the Bay Area now than mega cities like New Delhi, which are known for poor air quality," said Coty Jen, assistant professor at the Center for Atmospheric Particle Studies at Carnegie Mellon University.

Jen said even healthy people are reporting headaches and bloody noses during this current smoke event.

Air Quality

The EPA calculates a daily Air Quality Index based on five major pollutant on the Clean Air Act.

These are round-level ozone, particle pollution (also known as particulate matter), carbon monoxide, sulfur dioxide and nitrogen dioxide.

Fine particles pose the most serious health threat.

AirNow website said that these microscopic particles can penetrate deep into people's lungs.

These particles can cause a range of health problems like burning eyes and runny nose. Chronic heart and lung diseases can also be an effect.

"Exposure to particle pollution is even linked to premature death," EPA warned.

EPA said that surgical and cloth masks and bandannas do not protect against smoke inhalation. Higher-grade N-95 masks can be helpful but they are in short supply.

N-95 masks are mostly reserved for medical purposes too.

The Air Resources Board said people in affected areas to stay inside with their windows and door shut.

It also advised to run air conditioners in the recirculate setting and keep track of conditions.

California COVID-19

The state of California has registered around 673,000 of the 5.7 million cases of COVID-19 in the U.S.

Dr. John Watson, an expert on air quality measurements and the impact of air pollutants at the Desert Research Institute in Reno, Nevada, said that the prevalence of smoke only makes residents more vulnerable to COVID-19.

Watson said they are going to be more prone to have more damage. The smoke alone causes a lot of asthma, bronchitis, and bronchitis among others.

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