Environment & Science

Smog declined in Southern California over the last year

A hazy view from behind the Hollywood sign.
A hazy view from behind the Hollywood sign.
Photo by Steve Boland via Flickr Creative Commons

Listen to story

00:53
Download this story 0MB

Here's a breath of fresh air: Southern California's air continues to get cleaner.

That's according to the South Coast Air Quality District, which said we had 10 fewer high ozone days during 2015's peak smog season than the previous year. Ozone is the primary gas in smog and can damage lungs.

In total, there were only 82 days when smog levels exceeded federal standards for clean air. That may sound bad, but it’s better than in 2014 when there were 92 such days.

A high smog day is defined as any day in which the amount of ground level ozone reaches more than 75 parts per billion.

Typically, the region sees the most smog between May and October, in part because there is more sunlight which helps the chemical reaction that creates ozone pollution.

Joe Cassmassi with the Air Quality Management District said eco-friendly cars and pollution cutting programs helped cut down the number of smog days.

So did Mother Nature.

"We had two instances this summer where we actually had tropical moisture come over the area and give us rainfall," Cassmassi explained.

Rain can clean the air and helps prevents smog from forming. 

Next year the number of high smog days will likely jump, since new federal standards will take effect this winter.

The new standard for acceptable levels of ozone, as set by the Environmental Protection Agency, will be 70 parts per billion starting December 28th.

Under those criteria, Southern California experienced 112 days of high smog during 2015's peak season.

Officials at AQMD say they’re already working on new programs to cut smog even further next year. 

The EPA is giving California until 2037 to meet the new goal of zero days where ozone exceeds the federal limit.