Impact of emission mitigation on ozone-induced wheat and rice damage in India

In this study, we evaluate the potential impact of ground level ozone (O₃) on rice and wheat yield in top 10 states in India during 2005. This study is based on simulated hourly O3 concentration from the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem), district-wise seasonal crop production datasets and accumulated daytime hourly O₃ concentration over a threshold of 40 ppbv (AOT40) indices to estimate crop yield damage resulting from ambient O₃ exposure. The response of nitrogen oxides (NOx) and volatile organic compounds (VOC) mitigation action is evaluated based on ground level O₃ simulations with individual reduction in anthropogenicNOx and VOC emissions over the Indian domain. The total loss of wheat and rice from top 10 producing states in India is estimated to be 2.2 million tonnes (3.3%) and 2.05 million tonnes (2.5%) respectively. Sensitivity model study reveals relatively 93% decrease in O₃-induced crop yield losses in response to anthropogenic NOx emission mitigation. The response of VOC mitigation action results in relatively small changes of about 24% decrease in O₃-induced crop yield losses, suggesting NOx as a key pollutant for mitigation. VOC also contribute to crop yield reduction but their effects are a distant second compared to NOx effects