SAN JOSE-- The Santa Clara Valley and Livermore Valley typically see higher levels of air pollution than the rest of the Bay Area, according to the Bay Area Air Quality Management District.
Officials came to that conclusion after looking at historical data of the Bay Area's air quality over the past four decades.
Harmony Oswald loves hiking at the Santa Teresa County Park in San Jose. One of her favorite things about it is the view.
"You get a really great view of the city," said Oswald. "You can even see the downtown area."
From high above, Harmony has the perfect view of the city and the city's air quality.
"In the last week, I've been noticing when I've been up top, you can see a bit of haze and fog down in the city area, kind of laying down in there," said Oswald.
"Santa Clara Valley is a valley surrounded by hills and air pollution can get trapped there in the region," said Bay Area Air Quality Management District spokesperson Erin DeMerritt.
DeMerritt said the Santa Clara Valley and Livermore Valley have higher levels of air pollution than other parts of the Bay Area. The Air Quality District looked at data as far back as the 1980s for ozone pollution and smog and since 2000 for particulate matter in the Bay Area.
DeMerritt said higher air pollution has to do with the Santa Clara Valley and Livermore Vlaaey's topography and ozone pollution or smog from a combination of heat, sunlight and vehicle tailpipe emissions. Also, particulate matter can build up to unhealthy levels near the ground, settling into the valleys which can happen when there is a temperature inversion.
"So what happens is, you have a layer of warm air that acts like a lid over a layer of cooler air at the surface, and that can trap emissions from people burning wood in their fireplaces near the ground level," said DeMerritt.
Michael Carey has lived in the South Bay for 64 years. He said he sees the haze often.
"Santa Clara Valley tends to collect a little more I think than up near San Francisco," said Carey.
"During the times when the temperatures get a little warmer and you don't have the air blowing, there's definitely a haze. You can see it in elevation looking over the valley. You can definitely see the haze."
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