School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States.
Environ Sci Technol. 2014 Jan 21;48(2):903-8. doi: 10.1021/es4034793. Epub 2014 Jan 8.
We use a model of agricultural sources of ammonia (NH3) coupled to a chemical transport model to estimate the impact of U.S. food export on particulate matter concentrations (PM2.5). We find that food export accounts for 11% of total U.S. NH3 emissions (13% of agricultural emissions) and that it increases the population-weighted exposure of the U.S. population to PM2.5 by 0.36 μg m(-3) on average. Our estimate is sensitive to the proper representation of the impact of NH3 on ammonium nitrate, which reflects the interplay between agricultural (NH3) and combustion emissions (NO, SO2). Eliminating NH3 emissions from food export would achieve greater health benefits than the reduction of the National Ambient Air Quality Standards for PM2.5 from 15 to 12 μg m(-3). Valuation of the increased premature mortality associated with PM2.5 from food export (36 billion US$ (2006) per year) amounts to 50% of the gross food export value. Livestock operations in densely populated areas have particularly large health costs. Decreasing SO2 and NOx emissions will indirectly reduce health impact of food export as an ancillary benefit.
我们使用一个农业氨（NH3）源模型与化学输送模型耦合，以评估美国食品出口对颗粒物浓度（PM2.5）的影响。我们发现，食品出口占美国 NH3 排放总量的 11%（占农业排放的 13%），平均而言，它使美国人口对 PM2.5 的加权暴露增加了 0.36 μg m(-3)。我们的估计对 NH3 对硝酸铵的影响的适当表示敏感，这反映了农业（NH3）和燃烧排放（NO、SO2）之间的相互作用。消除食品出口的 NH3 排放将比将 PM2.5 的国家环境空气质量标准从 15 降低到 12 μg m(-3)带来更大的健康益处。与 PM2.5 相关的过早死亡增加所带来的价值（每年 360 亿美元（2006 年））相当于食品出口总价值的 50%。人口密集地区的畜牧业运营尤其具有较大的健康成本。减少 SO2 和 NOx 排放将间接地减少食品出口的健康影响，这是一个附带的好处。
