Washington: A study showed that the US government's rollback of its climate change and energy policy would lower the country's air quality by increasing emissions of health-damaging ozone.
The study published in the latest edition of journal One Earth found that with the combination of loosened regulations and a warming climate, 22 more US counties would fail to meet the current ozone safety standard in 2050.
Unlike ozone in the upper atmosphere, which protects the Earth from space radiation, ground-level ozone at high concentrations damage people's respiratory functions and reduce crop yields.
In the past few decades, regulations have prompted significant reductions in ground-level ozone. However, it remains one of the most difficult air pollutants to manage.
Shen Huizhong and his team from the Georgia Institute of Technology 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 were eased.
They found that relaxing energy policies would add 6.5 per cent more nitrogen oxides into the air compared to the scenario with the current policies still in place. The nitrogen oxides are precursors of ozone.
When the team took climate change into consideration, the effect on ozone precursor emissions was even more substantial. A warmer climate will encourage the release of volatile organic compounds, another ozone precursor, by plants, according to the study.
The researchers found that the combined 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 per cent increase in failing counties compared to the scenario of continued energy policies and no climate change.
The Trump Administration has kept relaxing regulations over pollution. Recent research from Harvard Law School and Columbia Law School showed that more than 80 environmental rules would be deregulated by the Trump Administration.