STEVE INSKEEP, HOST:
In the western United States, it's unseasonably hot and dry. Monday August program, we learned that California is experiencing its worst drought in recorded history. The extreme conditions are affecting farms, they affect water reservoirs, they increase the threat of wildfires. And then, there's the air quality.
NPR's Nathan Rott reports.
NATHAN ROTT, BYLINE: Standing up here at the Baldwin Hills Scenic Overlook in Culver City, California, you can usually see most of Los Angeles. You can see downtown LA, the Hollywood Hills, even the ocean, all the way to the west. Today though - and for the last couple of days - they've all been shrouded in a haze of gray.
Telvin McMillin just hiked up to the top of the hill and he's looking over towards the ocean.
TELVIN MCMILLIN: You can actually see the line of the smog and it's really disgusting.
ROTT: California's weird winter weather is having a big effect on air quality here. San Francisco has been socked in smog. Parts of the Central Valley have been on high alert, with fine particle counts that are more than three times the federal standard. And it's not just noticeable in the air.
DR. ALAN KHADAVI, ALLERGIST: Their throat is irritating them, and their chest is irritating them and patients who have never had asthma are complaining of cough and shortness of breath.
MCMILLIN: Dr. Alan Khadavi is an allergist in LA. He says he's been seeing far more patients than he normally does this time of year. The reason? California's long running drought. 2013 was the driest year on record in California and 2014 hasn't been any better.
ROTT: Anthony Wexler is the director of the Air Quality Research Center at UC, Davis. He says that drought can affect air quality in a lot of ways.
ANTHONY WEXLER: One, of course, is just dust.
ROTT: It gets blown into the air off of the parched landscape.
WEXLER: Yet another one are wildfires.
ROTT: Which Angelinos experienced just last week, when a fire engulfed nearly 2,000 acres like it was late August. It filled the air with smoke.
WEXLER: Another way is that when weather fronts come through, they kind of blow all of the air pollution out and we get a fresh start.
ROTT: And that's the key. Without a significant weather event - rain or wind - air just sits stagnant, collecting more and more pollution - which is bad news for West Coasters. Forecasters aren't predicting any rainstorms or significant weather events through the end of the month.
Nathan Rott, NPR News. Transcript provided by NPR, Copyright NPR.