The Fresno State community found it difficult to take a breath of fresh air this week as air quality dipped below federal health standards.

The San Joaquin Valley Air Pollution Control District issued an air alert warning on Monday. Air alerts notify Central Valley residents when smog levels may exceed health standards. That warning was lifted on Wednesday.

To quantify the level of pollution and the risk that it poses to certain groups, the pollution control district uses the Air Quality Index (AQI).

The AQI places the amount of pollution levels on any given day on a scale of zero to 500. Anything more than 100 on the AQI indicates that air conditions may be unhealthy for sensitive groups.

The pollution control district only releases its air quality forecasts 24 hours in advance. The air quality condition forecast for today is moderate and is expected to be 93 on the AQI scale.

Fresno may not be in the clear yet. Air quality conditions have relapsed and continued to decline since the air alert was lifted.
Warmer weather conditions forecast for the weekend may impact the problem.

“We’re anticipating, with high pressure building up again, that we’re going to have some more stagnant conditions and the ozone will probably increase,” said district spokesperson Janelle Schneider. “There’s the possibility that we might be seeing some more smoke impacts over the weekend.

“People who have respiratory conditions, small children, elderly people, people with compromised health situations””they’re more susceptible to [bad] air quality. But if the air quality is poor enough, everybody starts feeling the effects of it.”

Gary Sanger, a meteorologist with the National Weathers Service in Hanford, said the main cause [of bad air quality] is smoke from the Rim Fire up by Yosemite.

The fire, while mostly contained, is still producing a large amount of polluting smoke that sinks down to the Valley floor.

“Any time you have a high pressure system above the area like we have now””that’s giving us our warm temperature””that just creates an inversion that traps smoke, haze and dust all over the Valley,” Sanger said.

Higher temperatures tend to negatively affect air quality.

The National Weather Service is forecasting increased temperatures for Fresno over the weekend. This upward trend on the temperature gauge is expected to reach its apex today with a high temperature of 99 degrees.

The high temperatures are expected to decrease throughout next week.