Tropospheric Ozone and Ultraviolet B: Radiation Coupling Impacts on Sensitive Crops Yield at United State Department of Agriculture (USDA), Beltsville, Maryland

Over the past decades, annual average background surface ozone concentration [O3] and ultraviolet 'B' radiation have been identified as two major surface atmospheric factors that have been increasing annually, at different level based on local climate and weather conditions can potential affect agriculture in every aspect and affect crop yield. But in most places, the O3 increase with an average of 0.3 ppb per year due to anthropogenic and natural activities in the environment leading to increased air pollution exposure to sensitive crops. This increase has led to some environmental stresses that have led to phototoxicity and phytotoxicity in vegetation and human respectively. Due to the fact that both atmospheric factors have similar impacts on vegetation, lots of research studies carried have attributed the causes of vegetation damage to either one of these factor without clear distinction of the two. Up to date, there is no research publication on UV-B and O3 pairing impact assessment on sensitive vegetation in the environment, leading to necrosis and chlorosis. The objective here is to perform statistical analyses on the daily 8 hour ozone concentration and UV-B daily mean values (integrated over time, measured over a 10-year period 2006 – 2015) on vegetation during growing season. This approach would provide significant information of which of the factors dominates in sensitive crops level of stress and the frequency of vegetation exposure during growing season that could be used for policy making for O3 control in order to minimize the stressors impacts as well as selecting convenient time for growing sensitive crops. The following corn and soybean’s sensitivity threshold limit leading to sensitive crops damage are acquired from indoor and outdoor experiments and used as baselines for the trend analysis. For example for ozone 70 ppb and for UV-B is 12 kJ/m²/d.