Researchers at Columbia University’s Mailman School of Public Health analyzed data from 702 non-smoking pregnant women from low-income areas in North Manhattan and the South Bronx who wore a machine in a backpack for two days during their third trimester to measure the quality of surrounding air. Scientists found that the children of the women who had been exposed to high levels of polycyclic aromatic hydrocarbons (or PAHs) were nearly twice as likely to be obese by age 5 than the children of women exposed to lower levels, and 2.26 times as likely to be obese by age 7.
PAHs are most commonly the result of combustion, like that of diesel-burning trucks. Of course, air pollution from combustion has already demonstrated disproportionate, adverse effects on the populations of the South Bronx and Northern Manhattan—in 2006, a landmark study found that these areas have had some of the highest concentrations of air pollution in the city, as well as asthma hospitalization rates to match.
On mice, scientists have found that exposure to PAHs causes gains in fat mass and prevent the process by which fat cells normally get rid of lipids and shrink. Other studies on prenatal exposure to PAHs have found that they correlate to higher rates of anxiety, depression and lower IQ's in young children.
The new research adds extra weight (no pun intended, really) to the conflict surrounding the city's distribution of waste transfer sites. Areas like North Brooklyn and the South Bronx host more than their fare share of traffic-clogged, inefficient waste transfer sites and suffer the price in public health because of it. The real question is whether this research will add any urgency to solving some of the problem—clearly, the health consequences of air pollution aren't only limited to a person's lungs.