A study from UC Berkeley economists showed that environmental regulations were the primary driver of a 60 percent pollution decrease in the United States from 1990 to 2008, despite growth in industrial production.

The researchers found that stricter environmental regulations compelled manufacturing plants to reduce their pollution levels by cleaning up their production processes. This study, however, comes at a time when the Environmental Protection Agency has been trying to roll back environmental regulations under the current administration.

“One point I take away from this study is that if regulation has a role in decreasing emissions, rollback might increase pollutions,” said Joseph Shapiro, co-author of the study and associate professor in the UC Berkeley Department of Agricultural and Resource Economics. “Pollution is not going down because we’re producing fewer goods or different kinds of goods, but because we’re changing the process by which we produce these goods.”

The study refuted notions that the decrease in pollution was caused by the types of products made or by decreases in production, according to Shapiro.

Reed Walker, co-author of the study and campus associate professor in the Haas School of Business, said in a press release that while some argue that emissions have been reduced because of sending production of environmentally damaging products to countries such as China and Mexico, the study found that pollution reduction is primarily due to regulation.

Ethan Elkind, director of the Climate Program at the campus Center for Law, Energy and the Environment, said he hopes that the study will influence policymakers to maintain environmental regulations. Instead of being pressured into believing that clean air and water “destabilizes” the economy, Elkind hopes that policymakers will be “emboldened” by this research.

Elkind added that the research is a “real positive story for the environment” and that it shows that strong environmental policies can coexist with economic growth.

“Environmental policy is not inhibiting job growth, but encouraging it,” Elkind said. “We can see clean air benefits, clean water benefits and the economic benefits at the same time.”

The study examined data from more than 1,400 products made by U.S. plants and the effects of a broad group of environmental regulations, including the federal Clean Air Act, while looking at pollutants such as nitrogen oxides, sulfur dioxide and carbon monoxide.

The researchers categorized pollution reductions into reductions that could be explained by differences in the amount of manufacturing output, changes in the kinds of products and changes in how the products were made.

“I don’t have much to say about what this means for environmental legislation going forward, only to say that what was done in the past was effective at reducing emissions,” Walker said in an email.

Grants from the U.S. Department of Energy and the National Science Foundation partially funded the study, which will be published in the American Economic Review.