Surface ozone in the Indian region

Ozone (O3) is a dangerous air pollutant in terms of damage to crop plants and human health. It is phytotoxic to vegetation and a toxic agent for human health. Tropospheric ozone (O3) in the Indian sub-continent from Afghanistan in the west (60 E) to parts of Southeast Asian countries in the east (105 E) and parts of China in the north (45 N) to Sri Lanka in the south (0 N) is simulated with an episodic chemical transport model christened HANK for the spring and summer months (February–May 2000). O3 concentrations are mapped on the gridded region. It provides a general picture of the variations in the surface ozone concentrations in the different regions of the Indian sub-continent. Simulated O3 is compared with the measurements at Delhi, Ahmedabad, and the Arabian Sea. AOT40—a parameter that represents the accumulated dose of ozone over a threshold of 40 ppb is computed for the region. The Indo-Gangatic plain in the Northeast region of India has been found to have very high AOT40 and also much higher concentrations of O3 and CO compared to the rest of the Indian region. There is substantial temporal and spatial variation in O3 across the region due to meteorological conditions and anthropogenic emissions of precursor gases. O3 concentrations are higher in March compared to other months during February–May period. Northern region of India has higher concentrations of O3 then the southern region.