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Name: Penn
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Could you tell me the amount of ozone that is at ground level in a typically polluted city? Please tell me of any references that I can consult to elaborate on this subject.

In Wisconsin, the state Department of Natural Resources monitors and reports ground-level ozone data. You might try either the corresponding department in your own state government, or possibly your city health department. As for references, you could try your library, browsing through "smog," "air pollution," "ozone," etc. Sorry I could not be more specific.

Don Libby

Ground-level ozone is measured in parts per billion by volume (ppb). The law is that 120 ppb hourly average can only be exceeded once per year. A city like Mexico City gets up around 500 ppb. Los Angeles has cleaned up their act they are around 200 to 300 when bad and exceed 120 something like 200 days a year. Chicago, Houston, and the Northeast cities get up around 160 to 200 ppb. Other cities are polluted but not as bad, like 120 to 160. There are about 90 areas in all in the US where 120 pbb is exceeded. Ozone and the chemicals that make ozone are transported downwind so it is a difficult problem to resolve.

This is a very complicated subject. EPA maintains an AIRS data base with ozone values for each city that has an 800 number from which you could order data, if you are dying to get gory details. Otherwise contact your city or state air qualityagency.

Marc Fernau

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