By Robin Culverwell

PHILADELPHIA (CBS) — Again today, Philadelphia and its surrounding counties are under a “code orange,” meaning the air contains unhealthy levels of ozone.

Kevin Sunday, a spokesman for the Pennsylvania Department of Environmental Protection, says high temperatures trap ground level ozone, allowing it to “bake” in the hot sun.  And that, in turn, makes it difficult for those with sensitive respiratory systems to breathe.

His best advice is to avoid the outdoors when the ozone and heat are at their worst: during the midday hours and rush hours.  As an alternative, he says, going out in the evening or early morning is best.
Other ways people all help?

“Fueling their cars at night, carpooling or using public transportation, cutting down on electric usage.”

Overall, Sunday says, the air around us is getting cleaner, due in large part to more efficient cars, which are the biggest contributor to ozone pollution.