Concentration and flux-based risk assessments reveal large losses in mung bean production due to current ozone...

Surface ozone (O₃) is a phytotoxic pollutant that significantly reduces crop yields and poses serious health risks in India. This study quantifies mung bean yield losses in the year 2023 across Rajasthan using three established O₃ exposure metrics: the 7-h seasonal daytime mean concentration (0900-1600 h) (M7), accumulated daytime exposure above 40 ppb (0700-1800 h) (AOT40), and modelled phytotoxic ozone dose (above 3 nmol m^-2 s^-1, parameterized for integrated assessment modelling) (POD₃IAM). The results suggest that O₃ significantly reduces mung bean yields in all the districts of Rajasthan, particularly in northeastern districts like Jhunjhunu, Sikar, and eastern district Bundi, which face the highest exposure and relative yield losses (∼16% (M7) and ∼19% (AOT40) in Jhunjhunu and ∼12% (POD₃IAM) in Karauli). In 2023, district-wise losses ranged from 0.0 to 15.8% (M7), 4.0-18.8% (AOT40), and 0.1-12.0% (POD₃IAM), with economic impacts greatest in Nagaur, followed by Jodhpur and Churu. Estimated mung bean production losses (MPL) were 56,127 tonnes (M7), 69,509 tonnes (AOT40), and 81,180 tonnes (POD₃IAM), with corresponding economic cost losses (ECL) of 68.23 million USD, 84.50 million USD, and 98.68 million USD, respectively. The results identify high-risk areas for mung bean losses and highlight that reducing O₃ precursors could substantially narrow Rajasthan's yield gap, underscoring the need for more stringent air pollution abatement policies.