If You Breathe Air, Stay Inside -- It's Hot And The Air Quality Is So, So, So Terrible

By Riley Beggin & Elina Shatkin with Mike Roe

Thinking about going outside? Taking a jog? Or a walk? Or a crawl? You're going to want to dial back your outdoor activities and exercise during this week's prolonged heat wave. Beyond the risks of hot weather, the forecast also includes unhealthy air through Sunday.

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.

An ozone advisory has been issued that's in effect until Sunday. Sam Atwood with the South Coast Air Quality Management told KPCC during a similar event 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.

On behalf of our lung cells, no thanks.

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.

It's bad all over, but it's most likely to reach officially "unhealthy" or even "very unhealthy" levels in the Santa Clarita Valley, the San Gabriel Mountains, the San Fernando and San Gabriel valleys, the Inland Empire, and the San Bernardino Mountains.

Young children, the elderly, and people with asthma or other heart or lung conditions are especially vulnerable to complications from poor air quality. And even once the current warning ends, the heat is going to last into next week. Stay safe out there, friends of all ages.

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