According to the 16th annual State of the Air report released by the American Lung Association (ALA) on Wednesday, drought conditions are worsening air pollution throughout California.

ALA experts said that high levels of short-term particle pollution have been recorded in many Western cities, as well as Riverside County.

Fine particles of pollution close to the ground get trapped by low levels of precipitation, causing asthma attacks and hospitalizations for respiratory disease. The hotter weather also increases levels of ozone or smog in the air.

According to the ALA, smog's common sources include automobile exhaust and factories. Breathing it can shortness of breath, asthma attacks and increased risk of respiratory infection.

Alexander Sheriffs, a member of the California Air Resources Board and a family physician based in Fresno said, "With the increasing frequency of heat events, we can expect more stagnant air days, which will increase ozone days. Agricultural burning and wildfires, which are going to become much more common, will contribute to poor air quality".

According to Janice Nolan, vice president for national policy and advocacy at ALA, levels of air pollutants have been falling steadily since the 1990s, but are ticking back up in some communities.

Nolan added that many cities, especially in the West, had record numbers of days with high short-term particle pollution. These are often associated with wood smoke in wintertime. As part of the drought people are witnessing wildfires as well as dust blowing in the west.

The report gave Riverside County 'F' grades for ozone and for particle pollution. This indicated the county had unhealthy levels of both types of pollution.

Riverside was ranked second among California's counties for its number of days where ozone exceeded healthy levels. The county averaged 97 days per year with unhealthy ozone levels between 2011 and 2013.