Ozone levels, for example, are three times higher than the Federal standard.

Ozone levels must be cut by half again to meet Federal and state air laws.

Last year the ozone level had been reduced by 40 percent.

Ozone levels fall by over 60% during the worst years.

Since then, a general decline in ozone levels has been seen.

Ozone levels actually rose in 2002 and 2003 before falling again last year.

In the last 20 years, Ohio's ozone levels have dropped by 25 percent.

At that point the ozone levels climb back toward normal too.

A14 Scientists said ozone levels were the lowest in 14 years.

The third study also found an association, though a somewhat smaller one, between ozone levels and death rates.