FRESNO, Calif. (KFSN) -- As thousands of Central Valley students head back to school this week, the chances of unhealthy air quality increases.
High-pressure building over California in the summer creates an inversion layer that traps pollution on the Valley floor and increases ozone levels.
"That is because of increased traffic. So during this time frame, we ask parents to be mindful as much as possible when they are picking up and dropping off their children and not idle their vehicles and turn it off," said Cassandra Melching, San Joaquin Valley Air Pollution Control District.
She says they worked with Fresno Unified to put up signs outside schools encouraging parents to turn off their car's engine while waiting for their child.
"The reason for that is that because the exhaust that comes out of those tailpipes, it just doesn't automatically drift off into the air. It kind of hangs around lower levels. So those little kids are walking right through that," she said.
So far this summer Fresno County has had only three days of unhealthy air quality.
But Melching pointed out a lack of wildfires and cooler temperatures this summer are helping with better air quality.
Residents in the Central Valley can do their put to help out.
"You know, I try to carpool as much as possible and take lunches to work. Get into an electric vehicle or a low emission vehicle," said Melching.
The Valley Air District also suggests keeping your vehicles tuned up and avoiding the use of drive-through services.
Hot weather affecting the air quality as students return to school
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