The exterior of the US Environmental Protection Agency (EPA) is seen in Washington, DC, USA 21 September 2015. Photo by Jim LoScalzo/EPA

This story is part of a partnership between MedPage Today and VICE News.

Air pollution contributes to 16,000 premature births in the United States each year, costing $4.33 billion annually, a new study has found.

Most of the cost, $3.57 billion, is in lost productivity related to the physical and mental disabilities that arise from being born prematurely, Dr. Leonardo Trasande, an associate professor at New York University's Langone Medical Center, and colleagues reported in the journal Environmental Health Perspectives. The rest is spent on extended hospital stays associated with premature birth.

Trasande's study is the first of its kind to measure the economic implications of air pollution on preterm birth in the United States. After starting with preterm birth data from the Centers for Disease Control and Prevention and pollution data from the Environmental Protection Agency, Trasande and his colleagues drew from various previous studies to estimate the number of preterm births caused by air pollution in each US county.

Although air pollution includes the regular culprits like carbon monoxide and ozone, Trasande and his colleagues used particulate matter smaller than 2.5 micrometers as a stand-in for all air pollution. Particulate matter includes tiny particles of metals, acids, organic chemicals and other dust that can be floating in the air.

"Air poll causes inflammation, and inflammation in the placenta contributes to a lack of integrity of the blood vessels there and can also send hormone signals that can trigger early delivery," Trasande said.

They found that urban counties, particularly those in the Ohio River Valley and the southern part of the country, had the highest proportion of preterm births that could be attributed to particulate matter in the air.

Trasande and his team then estimated medical premature birth costs using information gleaned from a 2007 Institute of Medicine report, according to the study. They also estimated the IQ loss associated with premature birth and the subsequent loss of lifetime earnings for a child born in 2010.

"Because of the widespread exposure to [particles in the air], considerable health and economic benefits could be achieved through regulatory interventions that reduce such exposure in pregnancy," the authors wrote in their conclusion.

Air pollution kills 5.5 million people worldwide each year, causing heart disease, lung cancer and other diseases "on the same level" as smoking and poor diet, according to the Global Burden of Diseases report published last month.

The United States began its efforts to reduce air pollution in the 1970s, which includes measures to reduce pollutants from power plants, industry and vehicle emissions. Still, the US is the second highest coal producer in the world, beat out only by China, but a mix of government regulations, industry politics and market conditions have caused the U.S. to shift away from coal in recent years. Coal now accounts for about 35 percent of US electricity generation, down from 50 percent 10 years ago.

"In regulatory debates about reducing air pollution exposure, all too often we see one-sided arguments where the costs to companies are not put side-by-side with the benefits of prevention," he said. "We believe these data can be leveraged to support evidence-based policy changes that can reduce air pollution exposure."