POOR AIR QUALITY ADVERSELY AFFECTS PREGNANT WOMEN.

Byline: Staff and Wire Services

Pregnant women who breathe very smoggy air are at greater risk of giving birth to underweight babies - findings that raise health concerns in Los Angeles, the nation's smog capital, a study released Monday says.

Researchers at the University of Southern California analyzed the birth weight of nearly 4,000 California children born from 1975 and 1987, and the air pollution in the areas where their mothers lived during pregnancy. They found an increase in ozone levels was associated with lower birth weight.

``These findings add further evidence that our ozone standards are not protecting the most vulnerable members of the population,'' said Frank D. Gilliland, the study's senior author.

Ground-level ozone is created through tailpipe exhaust, gasoline vapors, industrial emissions and chemical solvents. It reduces hemoglobin's ability to carry oxygen to parts of the body, thus affecting a fetus.

``Fetal growth and birth weight are strongly linked to morbidity and mortality during childhood and adulthood, so it's clear that air quality is important to everyone's healthy development,'' Gilliland said.

The effects of ozone were strongest when the average daily exposure rose above 30 ppb.

The national ozone standard is 80 ppb over eight hours. The South Coast Air Quality Management District region, which includes urban Los Angeles County, exceeded that standard on 84 days this year.

Erica Lepping, a spokeswoman for the Coalition for Clean Air, said the research is a concern, particularly for Inland Empire communities where pollution from the ports, cars and trucks sits and transforms into ozone.