Volatile organic compounds from drilling and fracking operations together with nitrogen oxides, are responsible for 17 percent of locally produced ozone in Colorado’s heavily drilled Front Range. Colorado has exceeded federal ozone limits for the past decade, a period that corresponds to a boom in oil and gas drilling  Living near drilling and fracking operations significantly increases asthma attacks for residents of Pennsylvania, with those living near active gas wells 1.5-4 times more likely to suffer from asthma attacks than those living farther away, with the closest group having the highest risk

The New York State Department of Environmental Conservation determined that fracking could increase ozone levels in downwind areas of the state, potentially impacting the ability to maintain air quality that meets ozone standards. In California, fracking occurs disproportionately in areas already suffering from serious air quality problems and can drive ozone and other federally regulated air pollutants to levels that violate air quality standards. This increased air pollution and smog formation poses a serious risk to all those already suffering from respiratory issues, such as children with asthma. With an average of 203 high-ozone days a year, intensely fracked Kern County, California, is the fifth-most ozone-polluted county in the nation, according to the American Lung Association.

Several studies have documented a sharp uptick in atmospheric ethane, a gas that co-occurs with methane and whose presence is attributable to emissions from oil and gas wells. This trend reverses a previous, decades-long decline; if this rate continues, U.S. ethane levels are expected to hit 1970s levels in about three years. Ethane is a potent precursor to ground-level ozone. Emissions from drill site flaring operations also contribute to ozone creation and include several carcinogens, including benzene and formaldehyde. In 2016, the EPA acknowledged that it had dramatically underestimated health-damaging air pollutants from flaring operations. A 2017 study of plume samples from gas flares in North Dakota found that incomplete combustion from flaring is responsible for 20 percent of the total emissions of methane and ethane from the Bakken shale fields, which is more than double the expected value.