Relaxing US energy regulations would significantly lower air quality by increasing emissions of pollutants
According to the researchers, relaxing energy policies are expected to increase emissions of both greenhouse gases and conventional air pollutants, which are known to react in the atmosphere to form ozone, a pollutant harmful to humans
Relaxing US energy regulations will worsen air quality by increasing emissions of health-damaging ozone. Around 22 more counties in the US would fail to meet the current ozone safety standard in 2050 due to a combination of loosened regulations and a warming climate, according to researchers from the Georgia Institute of Technology, Atlanta, Harvard University, T.H. Chan School of Public Health, Boston; and Resources for the Future, Washington, DC, among other institutes.
The safety standard for ground-level ozone in the US is 0.070 ppm. Currently, says the team, more than 120 million people are living in areas with ozone concentrations that exceed this level.
"Past research has focused mostly on the link between energy policies and greenhouse gas emissions. Through our study, we hope to point out the impact of energy policies on air quality, which tends to be overlooked. For people, the findings imply that relaxing energy policies can lead to adverse impacts on people's health due to increased exposure to ambient ozone," first author Huizhong Shen from the Georgia Institute of Technology told MEA WorldWide (MEAWW).
"For policymakers, the findings imply that relaxing US energy policies can lead to extra hidden costs that are associated with ozone's adverse impacts on population health and also the costs in those states that are struggling to attain ozone standards. These states need to make more efforts to attain the ozone standards," adds Shen.
The analysis, published in One Earth, comes even as the Trump administration rolled back a US climate change and energy policy called the Clean Power Plan in June 2019. The policy, first instated in 2015, aimed to limit power plants' carbon emissions. According to the researchers, relaxing energy policies are expected to increase emissions of both greenhouse gases and conventional air pollutants, which are known to react in the atmosphere to form ozone, a pollutant harmful to humans.
"Our model shows that this rollback could come up with longer retention of existing coal-fired power plants, which would otherwise be retired if keeping on stringent energy policies. We also consider other energy policies. Altogether, relaxing these energy policies lead to higher fossil fuel use than that under stringent energy policies by 2050. Therefore releasing more nitrogen oxide and other air pollutants that are associated with ozone formation," Shen told MEAWW.
Shen adds, "We also put these changes in a changing climate and find that the impacts of these changes on ozone are amplified by climate change. Given that energy policies are created to reduce carbon emissions and prevent climate change, relaxing these policies is expected to increase ozone more than we previously thought if both changes in NOx emissions and climates are considered."
According to the research team, relaxing energy policies would reverse a current trend of decreasing ground-level ozone. Such an attitude to overlook the impact of energy policies on air quality may significantly undermine efforts to mitigate air pollution and protect human health, warn the researchers.
"Uncertainty in science, especially when it comes to climate change or energy policy, plays a huge role in affecting legislation. Lobbyists and politicians tend to use these uncertainties and emphasize the extremes to argue for their personal interests. As scientists, we want to speak with data and present only what the data shows us," says coauthor Yufei Li from the Georgia Institute of Technology.
Ground-level ozone is harmful
Unlike ozone in the upper atmosphere, which shields the Earth from space radiation, ground-level ozone is harmful to animals, plants, and humans at high concentrations.
According to the US Environmental Protection Agency (EPA), besides irritating the respiratory system, ozone can aggravate asthma and can inflame and damage the cells that line the lungs. "Ozone may also aggravate chronic lung diseases such as emphysema and bronchitis and reduce the immune system's ability to fight off bacterial infections in the respiratory system. Lastly, ozone may cause permanent lung damage. These effects can be worse in children and exercising adults," says the EPA.
In the past few decades, regulations have prompted significant reductions in ground-level ozone. However, it remains one of the most challenging air pollutants to manage, say experts.
Ozone in the air is not from direct emission but is formed in the air from emitted precursors. Chemical compounds, such as carbon monoxide, methane, non-methane volatile organic compounds, and nitrogen oxide, which in the presence of solar radiation react with other chemical compounds to form ozone, mainly in the troposphere, are referred to as ozone precursors.
Ozone is formed when nitrogen oxide gasses emitted from vehicles and factories react with volatile organic compounds in the air. "Ozone is a secondary pollutant. This means it's not emitted but formed in the air. Nitrogen dioxide and volatile organic compounds are two important ozone precursors that are emitted from either anthropogenic or natural sources. Consequently, we can't regulate it by simply cutting off its emitters, because it doesn't have any. We need strict emission policies that cut other pollutants to reduce ozone," says Shen.
The study findings
The researchers created a computer model to simulate how relaxing energy policies would affect ozone levels through 2050. In their scenario, they assumed that several US energy policies — the Clean Power Plan, Production Tax Credit, Investment Tax Credit, and the Corporate Average Fuel Economy standards on cars — have been eased.
"We chose this subset of energy policies not only because there have been many discussions around them but also because they target the power sector and the transportation sector. They are the two largest energy consumers and polluters in the country," says Li.
Analysis by the researchers shows that relaxing energy policies would add 6.5% more nitrogen oxides — which are ozone precursors — into the air as compared to the scenario with the current policies still in place.
When the team took climate change into consideration, the effect on ozone precursor emissions was even more substantial. A warmer climate, they found, would encourage the release of volatile organic compounds — another ozone precursor — by plants.
"The synergistic effects of relaxed energy policies and climate change would cause 17 to 22 more US counties to exceed the ozone safety standard in 2050. This represents a 63% to 81% increase in failing counties compared to the scenario of continued energy policies and no climate change," the findings state.
According to Shen, for people, living in an area that fails to meet the ozone safety standards means breathing ozone that is in a relatively unhealthier level. "There is no clear threshold under which ozone's adverse impacts suddenly disappear. Therefore, as long as the ozone level increases, it becomes more deadly. For the government, on the other hand, areas that fail to meet the ozone safety standards will face stringent penalties. Emission abatement to meet the standards could cost billions of dollars each year," Shen told MEAWW.