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) from electric power plants. In response to the observed changes in power plant NO 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 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.

中文翻译：

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减少污染带来的生产力溢出效应：减少煤炭使用可提高作物产量

空气污染会减慢光合作用，从而降低作物产量。我们估计美国玉米和大豆产量的增加归因于近期发电厂氮氧化物 (NO) 排放量的大幅减少。为了响应从 2003-05 年到 2011-13 年的八年间观察到的发电厂 NO 排放量的变化，我们估计平均玉米产量提高了 2.46%，大豆产量提高了 1.62%。这些改进意味着两种作物每年总盈余增加了 16 亿美元。根据 NO 排放量的变化，估计的产量提高在各州之间差异很大。对于玉米，它们的范围从 0.32% 到 6.87%，而对于大豆，它们的范围从 0.21% 到 4.30%。对这两种作物的需求相当缺乏弹性，这意味着价格下降幅度大于产量增长幅度，以应对这种积极的生产力冲击和作物供应曲线的隐含右移。由于美国玉米和大豆的供需弹性较低，我们从福利分析中得出的结论是，这些变化使消费者的状况变好，而农民的状况变差。