Understanding the effect of seasonal variability of VOCs and NO on the ozone budget and its photochemical processing over a rural atmosphere.

Ozone (O) in the troposphere is critically important because it serves as a significant oxidant, playing a vital role in atmospheric chemistry and influencing various environmental and health impacts. Several factors impact O formation which include precursor concentrations, meteorological conditions, and transport. In the present study, a rural observational site located in Gadanki (13.

Measurements of Volatile Organic Compounds at a rural site in India: Variability and sources during the seasonal transition.

Volatile Organic Compounds (VOCs) play a vital role in tropospheric ozone formation that controls the oxidative capacity of the troposphere. A total of 31 potential ozone precursor VOCs have been measured at a tropical rural site, Gadanki (13.5°N, 79.

Spatial variability of trace gases (NO, O and CO) over Indian region during 2020 and 2021 COVID-19 lockdowns.

COVID-19 lockdown has given us an opportunity to investigate the pollutant concentrations in response to the restricted anthropogenic activities. The atmospheric concentration levels of nitrogen dioxide (NO), carbon monoxide (CO) and ozone (O) have been analysed for the periods during the first wave of COVID-19 lockdown in 2020 (25th March-31st May 2020) and during the partial lockdowns due to second wave in 2021 (25th March-15th June 2021) across India. The trace gas measurements from Ozone Monitoring Instrument (OMI) and Atmosphere InfraRed Sounder (AIRS) satellites have been used.

Influence of background dynamics on the vertical distribution of trace gases (CO/WV/O) in the UTLS region during COVID-19 lockdown over India.

The COVID-19 pandemic lockdown has led to the significant reductions in the pollutant levels across the globe. Several studies have been carried out for examining and quantifying the improvement in the air quality due to the reduction of the pollution at the surface. Unlike most of the studies carried out earlier on COVID-19 lockdown, this study investigates the role of the dynamics on the vertical distribution of the trace gases (Carbonmonoxide (CO), Water Vapor (WV) and Ozone (O)) over India in the Boundary Layer (BL), Middle Troposphere (MT) and Upper Troposphere (UT) during COVID-19 lockdown using satellite observations and re-analysis data products obtained during 2010-2020.

Regional estimation of methane emissions over the peninsular India using atmospheric inverse modelling.

Accurate renditions of country-scale methane (CH) emissions are critical in understanding the regional CH budget and essential for adapting national climate mitigation policies to curtail the atmospheric build-up of this greenhouse gas with high warming potential. India housing 30% of the Asian population is currently appraised as a region of CH source based on the inventories. To date, there have not been many reported efforts to estimate the regional CH emissions using direct measurements of boundary layer CH concentrations at multiple locations over India.

Phase-wise analysis of the COVID-19 lockdown impact on aerosol, radiation and trace gases and associated chemistry in a tropical rural environment.

Phase-wise variations in different aerosol (BC, AOD, PM, PM and PM), radiation (direct and diffused) and trace gases (NO, NO, CO, O, SO, CO and CH) and their associated chemistry during the COVID-19 lockdown have been investigated over a tropical rural site Gadanki (13.5° N, 79.2° E), India.

Source apportionment of rainwater chemical composition to investigate the transport of lower atmospheric pollutants to the UTLS region.

Efforts to understand the chemical composition of Asian Tropopause Aerosol Layer (ATAL) in the Upper Troposphere Lower Stratosphere (UTLS) region have revealed the dominance of nitrates in the samples collected from ATAL layer during the recent balloon campaigns. Potential sources have been thought to be in-situ formation, convective uplift and long-range transport. Rainwater chemical composition consists water-soluble chemical ions that are wet scavenged during rain events and gives an indirect indication of lower atmospheric pollutants.

Quantitative Measurements of HO2 and other products of n-butane oxidation (H2O2, H2O, CH2O, and C2H4) at elevated temperatures by direct coupling of a jet-stirred reactor with sampling nozzle and cavity ring-down spectroscopy (cw-CRDS).

For the first time quantitative measurements of the hydroperoxyl radical (HO2) in a jet-stirred reactor were performed thanks to a new experimental setup involving fast sampling and near-infrared cavity ring-down spectroscopy at low pressure. The experiments were performed at atmospheric pressure and over a range of temperatures (550-900 K) with n-butane, the simplest hydrocarbon fuel exhibiting cool flame oxidation chemistry which represents a key process for the auto-ignition in internal combustion engines. The same technique was also used to measure H2O2, H2O, CH2O, and C2H4 under the same conditions.