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Blowin' in the Wind, Issue #083 Air Quality in California - June 1, 2011
June 01, 2011
Hello ,

Air Quality in California

The air quality in California air quality in California has improved over the course of the past twenty years. According to the California Air Resources Board, ozone (O3)and particulates, which are the main pollutants that were once measured at harmful levels, have been reduced significantly. Other substances of concern are lead, carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2).

These are now down to levels that are not considered health threats. Improvements in air quality are the result of a combination of better identification of pollutants, increased monitoring and enforcement of regulations.

Particulate matter, ozone, and other pollutants have been shown to lead to increased risks of respiratory diseases, cancers, breathing difficulties, and other chronic health problems.

Pictures of Air Pollution

When we think of polluted air, inevitably an image of yucky brown smog comes to mind. Sometimes pollutants that can be seen are still not present in measurably unhealthful levels. At other times particulate matter can be present in the air at unhealthful levels long before it can be detected by eye. Carbon monoxide cannot be seen or smelled.

The best way to know the actual pollution level on any given day is to check news outlets for the air quality index, or AQI. The United States Environmental Protection Agency developed the AQI as way of reporting air quality and possible health effects in a consistent and easily understandable way.

The EPA developed the AQI to provide accurate, timely and easily understandable information about daily levels of ozone and particulate matter air pollution. Newspapers, TV, radio, and web sites usually report pollution levels in terms of the AQI.


Photochemical smog occurs when chemical reactions occur between automobile and industrial emissions and sunlight, creating ozone. The smog condition worsens when accompanied by weather conditions known as thermal inversions, in which warm air that is heavy with particulates traps a layer of cooler air close to the ground. Air pollution in Los Angeles has a special situation. L.A. and neighboring California cities are set in geographic basins surrounded by mountain ranges, preventing the trapped air from escaping sideways. This makes the smog problems even worse, as contaminants from the city below continue to fill the trapped portion of the atmosphere. Yet, in recent years, smog problems in the area have become relatively rare.

There is a seasonal pattern to Air quality in California. Late winter and early spring are the times of year when air is generally best. Summertime, from June on into winter, is when it tends to be worst. There are regional variations as well, caused by micro-meteorological patterns and local topography.

The Air Resources Board is responsible for maintaining acceptable air quality throughout the state. It keeps track of air pollution levels through the use of monitoring stations in various parts of the state. The CARB sets standards for allowable concentrations of various pollutants in the air. They are responsible for enforcing those standards. The Board also sponsors ongoing research on both the health effects of air pollution and on the science behind improving Air quality in California.

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