Yale researchers recently received a $2.7 million grant to continue their research the effects of air pollution on birth outcomes.

The National Institute of Environmental Health Science awarded the grant to the principal investigators of the project in late July after they began applying for the funding in February 2010. The next step of the project, which began in 2008 with a $3 million grant from NIEHS, is to pinpoint specific sources of air pollution, the principal investigators of the project said.

Michelle Bell, professor of environmental health at the School of Forestry and Environmental Studies and one of the principal investigators, said the purpose of the research project is to analyze the components of particulate matter — solid and liquid particles of varying chemical composition — to determine which of these chemical components are most harmful.

Principal investigator Kathleen Belanger, research scientist and lecturer in epidemiology at the School of Public Health, said the project is important because it addresses an issue that affects all pregnant women.

“There are a variety of choices women can make to protect themselves, but they can’t choose not to breathe,” said Belanger.

Bell added that their research particularly focuses on the particle PM 2.5, which gets its name from its size: 2.5 microns.

These smaller particles are potentially more harmful than their larger counterparts because smaller particles can travel deeper into the lungs and cause more damage to a mother and her child, said Belanger.

PM 2.5 particles can contain chemicals such as sulfate, nitrate and metals, each of which can affect the body in harmful ways, said Belanger. She added that researchers hope to discover the relationship between mothers’ PM 2.5 exposure and the effects on her baby, such as pre-term delivery, low birth weight and unusually small size at birth.

Earlier in the course of their project, the team conducted research that involved collecting air samples in filters set up around Connecticut by the Department of Environmental Protection. The team weighed these filters to determine the amount of PM 2.5 present.

Bell and Belanger said their next goal is to determine the chemical components of PM 2.5 in hopes of determining the sources of this pollution.

“Right now there is a regulation treating all PM 2.5 particles as if they have equal toxicity, which we know and they know is not true, but the scientific community does not have enough information to help decision-makers know what types of particles are more harmful,” Bell added.

Belanger said the research team is currently in the process of cataloguing the filters received from the state of Connecticut, adding that they have begun analyzing 500 of 3,000 filters. Both she and Bell said confirming the hazardous nature of chemicals on pregnant women and fetuses would help yield more effective government regulations.

Belanger said in an email that the team would not have been able to conduct this second part of the study without the grant, as its costs would have been too high to cover independently.

“The current funding rates are quite small, so the vast majority of proposals that are submitted do not get funded, including some very outstanding ones, so we felt very fortunate to receive this award,” said Bell.

According to the EPA website, PM 2.5 can cause respiratory problems such as airway irritation, coughing, difficulty breathing and decreased lung function.