Paul Atkinson/KJZZ

Phoenix, Arizona.

You may have noticed a lot of High Pollution Advisories in the Valley this year. The advisories serve as a warning that our air has become dangerous to breathe based on standards set by the federal government.

Arizona used to be synonymous with clean air. In fact, people from all over the country suffering from breathing problems like tuberculosis and asthma used to come here to live in sanatoriums and tents. The thinking was the crisp, dry air would be good for what ailed them.

But over time rising levels of allergens and pollutants generated what we affectionately know as the Brown Cloud and that’s not good for people susceptible to respiratory problems.

In addition to dust and pollen, the Valley also has high levels of Ozone. This isn’t the stuff that protects us from the sun’s UV rays - that’s way up in the atmosphere. This is low level ozone, created when volatile organic compounds and nitrogen oxides react in the presence of sunlight.

“Researchers compare it to a sunburn on the lungs because it’s such a powerful irritant,” said Paul Billings of the American Lung Association. “It can trigger asthma attacks, but even for healthy adults they can start to get into trouble with their breathing on a high ozone day.”

Billings said Ozone causes lung inflammation and shortness of breath.

(Photo by Jimmy Jenkins - KJZZ)

Ben Davis runs the monitoring sites for the Maricopa County Air Quality Department.

The state and counties track Ozone levels and issue warnings based on the National Air Quality Standards set in the Clean Air Act. If Ozone levels rise above a certain threshold, the agencies issue what’s called a High Pollution Advisory. In Maricopa County this year, there has already been 26 HPA days due to Ozone.

Philip McNeely is the Director of the Maricopa County Air Quality Department. His agency regulates industries that produce precursors for Ozone.

“We’ll write a permit on how much they can emit, how many hours they can operate, what type of chemicals they can actually use," McNeely said. "That’s one way we control emissions going into the atmosphere.”

The county also operates 25 air quality monitoring sites around the valley.

There are three sites still detecting Ozone levels above the Federal standard. A long tube sticking out of the roof sends air down into a humming equipment room.

Ben Davis runs the monitoring for the County Air Quality Department. He points to a rack of sensors cranking out data. “You can literally watch the ozone levels increase and decrease in almost a real time method," Davis said. "Generally what we do for the EPA is an hourly average so we take one number every hour.”

One of the reasons Ozone is high in the East Valley is because of the geography.

Ira Domsky is a consultant with the Air Quality Department, he said polluted air gets trapped in the Valley and moves back and forth creating a sloshing effect. “So at night you kind of have the air creeping down the rivers and the streams and arroyos but in the afternoon, when the s surface of the Earth heats up, it drifts more up towards the mountains," Domsky said.

The East Valley monitoring sites are what’s keeping Maricopa County from meeting the EPA standards. The Clean Air Act requires the EPA to evaluate those standards every five years. They look at new scientific data and set thresholds to ensure public health.

In 2015 the EPA lowered the standard for Ozone from .075 to .070 parts per million.

Arizona Sen. Jeff Flake believes the new standard goes too far, too fast. He’s introduced legislation that would roll back the Ozone standard and move the review period back to every 10 years.

The American Lung Association’s Billings said postponing the standards means we’ll spend more time breathing bad air.

“We’ve made tremendous progress as a nation over the last 50 years because of the Clean Air Act," Billings said. "We need to continue that progress until every day is a clean air day in every city in the country.”

In the meantime it looks like Sen. Flake’s bill has resonated with the Trump Administration.

The new EPA director Scott Pruitt recently granted Arizona a year extension to meet the new Ozone standard.

(Photo by Jimmy Jenkins - KJZZ)

The monitoring sites take in air for testing at 25 sites across the county.

(Photo by Jimmy Jenkins - KJZZ)

This device monitors and records air quality data.