According to the findings of a new study, gas stations may release much higher levels of air pollution than experts previously believed.
Researchers from Columbia University and Johns Hopkins found that gas station emissions were 10 times higher than prior estimates, greatly increasing the risk to human health.
Not much is known about the release of fuel vapors from storage tanks at gas stations, including when it is released, the magnitude, or the health consequences it may pose for the public. However, prior studies have linked air pollution to increased risk of heart disease and reduced life expectancy. Air pollution is estimated to kill millions of people each year.
In this latest study, which was published in the journal Science of the Total Environment on September 24, researchers focused on studying actual emissions from two gas stations; one gas station in the Midwest and one in the Northwest.
Researchers measured emissions from gas station vent pipes and pressure in the storage tanks for three weeks at the two locations. They calculated the hourly atmospheric benzene levels, attached gas flow meters to the vent pipes and reported daily evaporative losses.
At the Midwest location, seven gallons were lost per day. At the Northwest location, three gallons were lost per day. Current California Air Pollution Control Officers Association estimates 0.11 pounds per 1,000 gallons are released each day.
Vent emissions measured more than 10 times higher than previous estimates, researchers noted.
In California, gas vents are set back 300 feet from large gas stations. At one gas station the emissions exceeded the threshold when measured at only 165 feet from the station, not the full 300 feet, the study noted. However, the second gas station’s emissions exceeded levels on two different days and up to 500 feet from the center.
Researchers say the findings are primarily due to non-compliant bulk fuel deliveries. It is likely people are exposed to harmful levels of benzene at gas stations even when they are more than 300 feet away from the vent pipes, they warn.
Long term exposure poses serious risks to humans, including a decrease in red blood cells, excessive bleeding, impaired immune system, increased infection risk, and increased risk of cancer.
The study’s authors called for changes to gas station vent pipe setback distances to help control emissions and prevent risk to humans.