Productivity Spillovers From Pollution Reduction: Reducing Coal Use Increases Crop Yields
研究美国电厂氮氧化物减排对玉米和大豆产量的影响，发现平均产量分别提升2.46%和1.62%，年总剩余增加16亿美元，但农民因价格下降而受损。
Air pollution reduces crop yields by slowing down photosynthesis. We estimate the increase in US corn and soybean yields attributed to the recent dramatic reductions in emissions of nitrogen oxides (NO x ) from electric power plants. In response to the observed changes in power plant NO x emissions over the eight‐year period from 2003–05 to 2011–13, we estimate that average corn yields improved by 2.46% and soybean yields by 1.62%. These improvements imply an increase in total surplus of $1.60 billion annually across the two crops. The estimated yield improvements vary substantially across states depending on the change in NO x emissions. For corn, they range from 0.32% to 6.87% and for soybeans, they range from 0.21% to 4.30%. The demand for the two crops is quite inelastic, which means that prices decrease by more than production increases in response to this positive productivity shock and the implied rightward shift of the crop supply curve. Due to the low elasticities of supply and demand for U.S. corn and soybeans, we conclude from a welfare analysis that these changes made consumers better off and farmers worse off.