High ozone levels are to blame for the recent advisories. Not to be confused with atmospheric ozone, which protects us from the Sun’s ultraviolet rays. This is low-level ozone, a pollutant that comes from the marriage of sunlight and volatile organic compounds in the air - mainly car exhaust.

Summertime in Phoenix is rife with both sunshine and cars, and air quality meteorologist Michael Graves said a stubborn high pressure system is making matters worse.

“Things are less likely to move, there’s less mixing," Graves said. "So when you have ozone forming and there’s less mixing it’s just going to accumulate because it’s not moving out.”

High ozone levels can trigger allergy symptoms and are dangerous for people with asthma, young children and the elderly. If you have to be outside, Graves recommends limiting your exertion.

The Arizona Department of Environmental Quality issues a High Pollution Advisory when ozone levels exceed 70 parts per billion. The EPA recently lowered the standard from 75 parts per billion.

There were 36 HPA days in Maricopa County in 2016 and county officials say we are on track for more this year.