The Environmental and Energy Study Institute (EESI) welcomes new ozone standards that will further protect public health from the negative respiratory, developmental, and other health effects of ozone exposure. The new standards, set at 70 ppb (down from 75 ppb), seek to strike a balance between health benefits and compliance costs, although public health groups have argued for a more rigorous standard. In setting the standard, the Environmental Protection Agency (EPA) has left out a major contributor to ozone – tailpipe exhaust. Tackling tailpipe exhaust provides the opportunity to further cut ozone emissions without excessive cost.

“Reducing ozone further presents a conundrum for states. While ground-level zone is unsafe at any level, reducing ozone precursors further from industry and utilities will be quite expensive,” explains EESI Policy Associate Jessie Stolark. “Luckily, EPA and state regulators have a virtually unregulated ozone contributor they can address: transportation fuels and their resultant tailpipe emissions.”

As car manufacturers work to make more efficient and cleaner engines, oil companies have gotten a free pass from regulators. The Volkswagen emissions scandal points to the difficulty of creating a cleaner car on existing petroleum fuels. According to the Department of Energy’s Quadrennial Technology Review, fuels and engines need to be co-optimized to reduce both greenhouse gases and air toxics.

“If we are to make true progress on ozone and greenhouse gases, we must address the fuels—just as we are addressing the engines,” stated Stolark.

Ozone, commonly referred to as smog, is a complex mixture formed when air pollutants react with each other in the presence of sunlight. Ground-level ozone impairs lung functioning and contributes to increased incidences of asthma and other lung diseases, especially among children and the elderly.

Tailpipe emissions from gasoline and diesel vehicles release ground-level ozone and other potent air toxics, including particulate matter and polycyclic aromatic hydrocarbons (PAHs). Research has shown that gasoline exhaust is the largest contributor to ground-level ozone in the urban environment. With 45 million individuals living, working, and going to school near roadways, reducing exposure to traffic-related ozone will have a substantial positive impact on health.