1.   A federal study released Tuesday reported that some of the additives used in the new fuel did not do much to reduce urban smog.

2.   But ethanol also tends to make gasoline evaporate easily, and in so doing adds to urban smog.

3.   For years, electric cars and vans powered by lead-based batteries have been promoted as a way to reduce health-damaging urban smog.

4.   One rule established tough new limits on ground-level ozone, a major contributor to urban smog.

5.   Ozone, a respiratory irritant linked to lung damage in some studies, is the main ingredient of urban smog.

6.   Pollution from older facilities has been linked to a host of problems, including premature deaths, respiratory aliments, urban smog and acidified lakes and rivers.

7.   Sulfur dioxide is the primary cause of acid rain, and the nitrogen compounds are precursors of urban smog.

8.   The study did not question the overall effectiveness of reformulated gasoline in reducing ozone, a component of urban smog.

9.   These include premature deaths, respiratory aliments, urban smog and acidified lakes and rivers.

10.   Urban smog has a pulverized radiance.