UV-B SCREENING BY TROPOSPHERIC OZONE - IMPLICATIONS FOR THE NATIONAL AMBIENT AIR-QUALITY STANDARD

Tropospheric ozone reduces human exposure to harmful ultraviolet-B (UV -B) radiation. A 10-ppb decrease in seasonal average concentrations of ozone (about 20%) is estimated to lead to increases in cancers and ca taracts valued at $0.29 billion to $1.1 billion annually. EPA in its o ngoing review of the National Ambient Air Quality Standard for ozone s hould set a standard to minimize all identifiable health effects, incl uding UV-B radiation-related effects. If these estimates are confirmed , this approach may reduce avoidable cancers, cataracts, and deaths by leading to a different standard than that recently proposed in a prog ram already costing more than $20 billion annually.