Observed variability of Surface Ozone (O3) and its Precursors over the Indian Capital region

Ozone (O₃) is a greenhouse gas which plays different roles in stratosphere and troposphere. It also has an important role in radiative and chemical balance of the atmosphere, and thus the changes in O₃ have greater climatic implications. Although O₃ is present in trace amounts in troposphere, it is adequate to govern the oxidation processes in the Earth’s atmosphere by forming OH radicals, as the atmospheric lifetime of many gases is controlled by OH radicals. Rapidly developing countries in tropics and subtropics have realized the importance of tropospheric O₃ studies as these regions have very limited measurements of ozone and its precursor gases. Understand the variability of the surface O₃ and their association with precursors are extremely important for the policy decisions to mitigate the impacts of ozone on human health and crops and ozone air quality management issues in the region. This study investigates the variability of surface ozone (O₃) its association with its precursors (NO, NO2, NOX, CO) at time scales of annual, seasonal and diurnal scales for the duration of three years using ground-based observations from IMD Ayanagar, IMD Lodhi road, CRRI, CV Raman, IGI Palam stations in the Indian Capital region. Further, we will present the back-trajectory analysis to elucidates the transport mechanisms/ pathways on the variability of ozone for the study region.