Mothers who breathe the kind of pollution emitted by vehicles, coal power plants and factories are significantly likelier to give birth to underweight children than mothers living in less polluted areas, according to international findings.
The study is believed to be the largest to examine how newborns' bodies are affected by air quality, an issue that has raised particular concern in China and other developing nations.
Nearly 30 researchers based their conclusions on more than 3 million births at 14 sites in North America, South America, Europe, Asia and Australia.
Weighing less than 5.5 pounds at birth is a factor for chronic health issues in childhood, including a higher risk for infection and developmental delays, experts say. Problems in adulthood can include cardiovascular disease, diabetes and other metabolic disorders.
"Being low birth weight basically is like you're starting at a little bit of disadvantage in terms of health throughout your lifetime," said Tracey Woodruff, the study's co-principal investigator and director of UCSF's Program on Reproductive Health and the Environment.
For the study, which appears in the journal Environmental Health Perspectives, researchers looked at two types of air pollutants, including inhalable coarse particles, which are about 10 micrometers in diameter and often appear in natural elements such as dirt, dust and sea salt.
Read more from San Francisco Chronicle.