When the A.Q.I. reaches 100 or more, outdoor air is no longer safe for sensitive groups.
Air pollution affects people all year, not just during wildfire season. On Aug. 24, smoke from wildfires raging in the Bay Area made the air quality four times worse than in Beijing or New Delhi. Three days later, the E.P.A’.s smoke map showed much of Northern California buried under a dark gray haze.
Mr. Tasat said that from Aug. 18 to 24, the daily average particle pollution level in California was about 500 percent higher than it was the same week in 2019, largely because of the wildfires.
However, California is subject to air pollution throughout the year. Sometimes there are high levels of both ozone and particle pollution during a particular season. Ozone pollution tends to be worse in the summer, Mr. Tasat said.
Fine particles in the soot, ash and dust of wildfire smoke make up particle pollutants, which can be inhaled by the lungs. During summer, the mixture of smoke pollutants and hotter temperatures generate what Ms. Holmes-Gen calls a “double whammy of ozone pollution and particle pollution.”
“One unique aspect of this time period, unfortunately, is that people can be affected by multiple types of air pollution,” she said.
You can reduce your exposure to air pollution. The effects of air pollution can be mild, like eye and throat irritation, or serious, requiring hospitalization for heart or respiratory issues. Smoke and pollution can cause inflammation of the lung tissue and increase the vulnerability of infections, Ms. Holmes-Gen said.
The most effective way to reduce your exposure to air pollution is to stay indoors with windows and doors closed, said Melanie Turner, a public information officer for the California Air Resources Board. Air-conditioning should remain on continuously, not the auto cycle, which cycles on and off, Ms. Turner said. It’s also helpful to close the fresh air intake so that smoke doesn’t get inside the house. If your system allows for it, it’s recommended to install a high efficiency air filter, classified as MERV 13 or higher. Portable air cleaners can also reduce indoor particulate matter in smaller spaces, like individual rooms. CARB certifies all air cleaners that are currently sold in California to ensure they meet its regulations for ozone emissions.