PM2.5 linked to lower weight in newborns
Exposure to high levels of fine particulate matter may lead to births of smaller babies an EPA study has found.

The study, published in the journal Pediatrics yesterday, said 9.2 pct of women who lived in areas with highest levels of fine particulate matter (PM 2.5 )gave birth to babies below average weight, compared with 8.5 pct of women with the least exposure to PM 2.5 .In other terms, women in the most polluted areas were 26 pct likely to give birth to smaller babies than those with low levels of PM 2.5 .

The difference in weight -about one ounce on average -was slight, but may be indicative of other health problems, said Jennifer Parker, the lead author of the study. She said the study did not determine whether PM 2.5 affects the fetus directly or whether it is the mother 's health that is affected by the pollution. The study, organized by EPA 's Office of Policy and Economic Innovation, focused on more than 18,000 births across California, measuring newborns 'weight and levels of PM 2.5 in the areas where their mothers lived in the nine months before giving birth.

Los Angeles and the Central Valley have highest levels of PM 2.5 in the US, registering the highest number of newborns below average weight.

The study divided pregnant women into four groups, according to levels of exposure to PM 2.5 and carbon monoxide. One question that was not answered was the effect of extreme exposures to PM 2.5 on newborns ' health.

The study is the latest yet to point to negative effects of particulate matter. EPA is conducting studies in six cities across the county to determine the effects of PM 2.5 on health, including a more specific look the link to heart and respiratory ailments. Electric Power Research Institute (EPRI) is also conducting a study in Atlanta (ARIES)on adverse health effects of PM 2.5 with a specific focus on the impact of different components. EPRI 's research has shown that not all of PM 2.5 components pose equal risk to health, and that carbon-containing components are the most deadly.

Last month EPA designated 225 counties located in 20 states as non-attainment with the new federal standard for PM 2.5 . Each will have to take steps to reduce pollution by 2008 (AAD 12/17/04.)

EPA also released a report last month that showed PM 2.5 levels across the country to be at their lowest in three decades and set to decrease even further as new regulations come into place. EPA estimated that current and proposed regulations will reduce direct PM 2.5 emissions by 200,000 tons/yr and cut volatile organic compounds by 3mn tons/yr by 2015,compared with 2001 levels.