Assessment of Synergistic Impact of Ambient Surface Ozone and Fine Particulate Matter on Experimentally Grown Wheat Crop

Abstract

The present study aims to understand how increasing surface ozone and fine particulate matter concentrations affect wheat crop productivity under ambient conditions. A pot experiment was conducted spanning over a period of 117 days starting from December 2016 to April 2017 at one of the receptor locations in Delhi characterized with high levels of surface ozone and fine particulate matter. The study site recorded highest concentrations of PM1, PM25, PM10 and surface ozone of 159±77 µg m−3, 172±79 µg m−3, 280±108 µg m−3 and 335±18 µg m−3, respectively during the crop cycle indicating the high levels of air pollutants at the site. The crops were treated with ascorbic acid under different experimental setups. A large number of growth, biochemical and yield parameters were evaluated at the vegetative, reproductive and grain formation stage of the crop cycle. Results indicated that the chlorophyll content and harvest yield of crops grown under ambient conditions were ∼23% and ∼14% lower than those of crops grown under controlled environment. Furthermore, a ∼13%, 5%, 15% and 10% decline in root length, plant height, number of tillers and number of leaves was observed in crops that were exposed to only surface ozone in comparison to crops exposed to only fine particulate matter under vegetative stage, respectively. Relative water content, chlorophyll content and air pollution tolerance index observed ∼56%, 23% and 61% decline with fully exposed setup in comparison control setup in the vegetative stage, while ∼57%, 23% and 44% decline was observed in the reproductive stage. Experiments also suggested that surface ozone had a more pronounced influence on overall productivity of wheat crops in comparison to fine particulate matter.