Air pollution emissions from U.S. manufacturing declined by 60 percent during 1990-2008, a period in which manufacturing output grew significantly. The emission reduction is largely attributed to federal environmental regulations and attendant adoption of cleaner production methods, according to University of California-Berkeley researchers.
Newly available data on over 1,400 different products produced by U.S. plants during the study period were analyzed and combined with plant-level pollution emissions data. Reductions in overall emissions were then categorized into those that can be explained by changes in manufacturing output, changes in the types of goods produced or changes in production technologies.
Most of the decreases in emissions of important pollutants from manufacturing, such as nitrogen oxides, sulfur dioxide and carbon monoxide, were associated with changes in production technologies. To identify the key driver of this trend, the researchers quantified the importance of reductions in tariffs and other trade costs, improved productivity and environmental regulation in explaining decreases in air pollution emissions. The stringency of environmental regulation for manufacturing firms was shown to nearly double between 1990 and 2008. This increase, rather than improvements in manufacturing productivity or trade exposure, accounted for most of the decreases in pollution emissions.