U.S. Regions With Highest Air Pollution Are in Calif., Report Finds

The five U.S. metropolitan areas with the highest air pollution rates are located in California, according to the American Lung Association's annual State of the Air report, the Vallejo Times-Herald reports (Rohrs, Vallejo Times-Herald, 4/30).

Details of Report

The 2014 report was based on quality-assured data that were collected from official monitors from 2010 to 2012.

The report ranked cities and counties based on:

• The average number of unhealthy days for ozone and short-term particle pollution; and
• Annual averages for year-round particle pollution.

National Findings

Despite major improvements in U.S. air quality, researchers found that about 147.6 million individuals -- about 50% of U.S. residents -- live in counties with unhealthy levels of air pollution (ALA release, 4/30).

According to the report, air quality declined between 2010 and 2012, but there still is less air pollution nationwide than 10 years ago (Rohit, Los Angeles Westside Today, 4/30).

The report noted that 13 of the 25 U.S. cities with the worst rankings reached their lowest air pollution levels yet.

Calif. Cities Top List of Most-Polluted Areas

ALA's annual report has regularly found California to have the most-polluted air in the U.S.

According to the 2014 report, Los Angeles-Long Beach had the highest level of ozone pollution nationally, followed by:

• Visalia-Porterville-Hanford;
• Bakersfield;
• Fresno-Madera; and
• Sacramento-Roseville.

Meanwhile, Fresno-Madera had the highest level of short-term particle pollution nationally, followed by:

• Visalia-Porterville-Hanford;
• Bakersfield;
• Los Angeles-Long Beach; and
• Modesto-Merced.

The five U.S. areas most polluted by long-term particle pollution are:

• Fresno-Madera;
• Visalia-Porterville-Hanford;
• Bakersfield;
• Los Angeles-Long Beach; and
• Modesto-Merced (ALA release, 4/30).

Reasons for High Air Pollution in Calif.

According to the ALA, improving air quality in California is difficult because of:

• The large population; and
• Weather and geography challenges.

According to the group, "Sunny weather and other conditions in the basin allow smog to form more easily," adding, "Surrounded by mountains on three sides, pollutants are also easily trapped as stagnant air lingers in the basin."

Report Recommendations

The report recommended that regions continue to focus monitoring efforts on pollution "hotspots," including:

• Freeways;
• Major roadways;
• Ports;
• Rail yards; and
• Trucking centers.