Dial back your outdoor activities and exercise during this week’s prolonged heat wave: Officials have forecast unhealthy air quality through the rest of the week.
If you do want to go outside and get moving, the best time is early in the morning or after sunset, when ozone levels will be at their lowest.
Sam Atwood of the South Coast Air Quality Management told KPCC how high ozone levels can exacerbate existing heart and lung disease symptoms.
"Ozone high in the stratosphere protects us from harmful ultraviolet radiation, but down close to the ground it can kill lung cells,” Atwood said.
Higher temperatures mean more ozone in the atmosphere. High temperatures also usually come with high air pressure.
“These high pressure systems create what’s called an inversion layer: Basically a lid on the atmosphere that traps the pollution relatively close to the ground and allows it to build up to unhealthy concentrations,” Atwood said.
When ozone levels rise, so do emergency room visits and hospitalizations.
Young children, the elderly and people with asthma and other heart or lung conditions are especially vulnerable to complications from poor air quality.
Areas that will be experiencing the highest levels of ozone pollution this week are the San Gabriel Valley, the San Fernando Valley, the Inland Empire and the San Gabriel and San Bernardino mountains.