The Trump administration says the current Environmental Protection Agency (EPA) standard for nitrogen dioxide pollution concentrations should stay in place.
The agency said it has completed a scientific review of the nitrogen dioxide standard from 2010 and determined that it is sufficiently protective of public health.
“EPA proposes that the current [standards] don’t need to be changed because they provide the appropriate public health protection, with an adequate margin of safety, including for older adults, children and people with asthma,” an agency spokeswoman said in a statement.
The EPA released a formal proposal Monday to keep the current limits in place. It will take public comments on the proposal before making it final.
Nitrogen dioxide is a pollutant from burning fossil fuels and comes primarily from vehicles, power plants and industrial facilities. Inhaling it can exacerbate asthma and other respiratory illnesses.
The current limit for nitrogen dioxide concentrations in ambient air are 53 parts per billion averaged over a year and a maximum 100 parts per billion for a one-hour period.
Stricter limits would mandate that states and localities find ways to reduce pollution, like limiting development.
The EPA’s Clean Air Scientific Advisory Committee, a group of outside scientific advisers, recommended in April to keep the existing standard, based on its review of the scientific literature.
The agency is required to review the nitrogen dioxide for potential changes every five years under the Clean Air Act’s National Ambient Air Quality Standards provision.
Environmental groups led by the Center for Biological Diversity sued the EPA last year, saying it missed its deadline. The EPA settled the case and agreed to complete its review this year.
No areas in the United States are known to exceed the nitrogen dioxide limits, the EPA said.