(117p) Elevated Tropospheric Ozone Impacts on Soybean Production in the United States from 1985 to 2015

Tropospheric or ground-level ozone (O3) is one of the hazardous and criteria air pollutants formed in photochemical reactions from precursor compounds such as nitrogen oxides (NOx), volatile organic compounds (VOCs), and carbon oxides. As a phytotoxic air pollutant, tropospheric ozone can damage the agricultural ecosystems, especially crop yield losses and economic losses of several important crops such as wheat, soybean, and rice. It is important to quantify the potential impacts of ozone on crop yield to ensure the current and future food security for the increasing population growth and demand. Difficulties of direct measurements of ozone and potential environmental factors make it harder to obtain actual impact of ozone on crops. Also, sparsity of ozone monitoring stations particularly in rural areas, makes it difficult to identify the potential impacts of ozone on agriculture. This will lead to a severe threat for crop production in the upcoming decades. With the increased emissions of ozone precursors specially carbon dioxide (CO2), tropospheric ozone is projected to increase 40-60% by year 2100 in comparison to current ozone concentration with huge economic loss. To evaluate the crop loss and economic loss, we used the estimates of national, county-level soybean production for the years 1985- 2015 from the United States Department of Agriculture’s (USDA) National Agricultural Statistics Service (NASS). We used the estimates of annual averaged, ground-level ozone that cover the contiguous United States from 1985-2015 (the average during May through September of the daily maximum 8-hour moving average) at the county level from Land Use

Regression (LUR) models. Considering pre-industrial ozone level based on the United States Environmental Protection Agency (USEPA), we estimated national soybean loss and economic loss from 1985 to 2015. We found average 2 billion of soyabean bushels lost each year during 1985 to 2015. Also, we calculated average 20-25 billion of dollars lost each year during 1985 to 2015. Some states such as Iowa, Illinois, Indiana in the Mid United States experience huge soyabean and economic loss during 1985 to 2015. This information will help environmental regulators to make effective environmental regulations controlling ozone emissions to provide not only food security, but also economic benefits.