Ashish Kumar

University of York · Department of Chemistry

Accurate emission inventories serve as critical inputs for air quality and climate models, but are poorly constrained over India. We present a new municipal open waste burning emission inventory from India (OWBEII), at a resolution of 0.1° x 0.1°. Out of the 216 (201-232) Tgy⁻¹ of waste produced in the year 2015 68 (45-105) Tgy⁻¹ was burned in the...

In complex atmospheric emission environments such as urban agglomerates, multiple sources control the ambient chemical composition driving air quality and regional climate. In contrast to pristine sites, where reliance on single or a few chemical tracers is often adequate for resolving pollution plumes and source influences, the comprehensive chemi...

Every year in the post-monsoon season, ~1.7 billion tons of paddy stubble is burnt openly in the Indo-Gangetic Plain (IGP) producing persistent smog and air quality deterioration that affects the entire IGP. Information concerning the identity, amounts and spatial distribution of volatile organic compounds (VOCs) which drive ozone and aerosol forma...

21 of 30 most polluted cities for particulate matter (PM2.5) are in India, yet the distribution, identity and emissions of volatile organic compounds (VOCs) from traffic, which are PM2.5 and ozone precursors, remain unknown. Here, we measured emission factors (EFs) of 74 VOCs from a range of Indian vehicle-technology and fuel types. When combined w...

During wintertime, the Indo-Gangetic Plain suffers from severe air pollution affecting several hundred million people. Here we present unprecedented measurements and source analyses of 52 NMHCs (25 alkanes, 16 aromatics, 10 alkenes and one alkyne) in the cities of Delhi and Mohali (300 km north of Delhi) during wintertime (Dec 2016–Jan 2017). NMHCs...

Night-time oxidation significantly affects the atmospheric concentration of primary and secondary air pollutants but is poorly constrained over South Asia. Here, using a comprehensively measured and unprecedented set of precursors and sinks of Stabilized Criegee Intermediates (SCI), in the summertime air of the Indo-Gangetic Plain (IGP), we investi...

The Indo-Gangetic Plain experiences significant air pollution during the winter, affecting hundreds of millions of people. During the WiFEX (Winter Fog Experiment) campaign in the winter of 2016-2017, we conducted unprecedented measurements and source studies of 52 NMHCs (25 alkanes, 16 aromatics, 10 alkenes, and one alkyne) in the cities of Delhi...

Traffic emissions are a major source of air pollution and associated damage to human health in India. Many of the Indian metro cities urgently require cleaner transportation technologies to ensure cleaner air. Here, using newly compiled spatially disaggregated, gridded, high-resolution (0.1° × 0.1°) road transport emission inventory for India for 2...

A new hybrid gridded emission inventory for paddy stubble burning in Punjab and Haryana (Northwest India) in 2017. The emission inventory was compiled using the emission factors (EFs) measured from on-field fires (both flaming and smouldering fires) and combined with 1 km × 1 km stubble burning activity constrained by annual crop production yields...

At present, urban planners select tree species for urban plantation based on the size, aerodynamic properties, the aesthetic value of trees and the tree's air pollution tolerance and rank choices based on an anticipated performance index (API). The index does not consider whether the chosen species will aggravate the pollution by emitting highly re...

Background: Nitrous oxide has been used during surgical anesthesia for many years. However, information about occupational exposure and related risks due to N2O exposure to the health care personnel in India are still poorly understood. Here, we measured the residual N2O levels during the working time of operation theatre room air in our tertiary...

Approximately 1.7 billion tons of paddy stubble is burnt openly in the Indo-Gangetic Plain (IGP) every year during the post-monsoon season. This large-scale biomass burning activity over two months results in massive emissions of reactive organic and particulate species that exacerbate the problem of persistent smog and air quality deterioration ov...

Trees significantly impact land-atmosphere feedbacks through evapotranspiration, photosynthesis and isoprene emissions. These processes influence the local microclimate, air quality and can mitigate temperature extremes and sequester carbon dioxide. Despite such importance, currently only 5 out of 15 atmospheric chemistry climate models even partia...

Tropospheric ozone is a major pollutant and it is harmful for humans at sustained exposures of 40 ppb or more in ambient air. In this study we calibrate the deposition of ozone for stomatal exchange (DO3SE) model for Polyalthia longifolia (False Ashoka), a tree that accounts for 5-20% of the urban plantations in Indian cities and subsequently use t...

Abstract. In complex atmospheric emission environments such as urban agglomerates, multiple sources control the ambient chemical composition driving air quality and regional climate. In contrast to pristine sites, where reliance on single or few chemical tracers is often adequate to resolve pollution plumes and source influences, comprehensive chem...

Biogenic volatile organic compounds exert a strong influence on regional air quality and climate through their roles in the chemical formation of ozone and fine-mode aerosol. Dimethyl sulfide (DMS), in particular, can also impact cloud formation and the radiative budget as it produces sulfate aerosols upon atmospheric oxidation. Recent studies have...

Biogenic volatile organic compounds exert a strong influence on regional air quality and climate through their roles in the chemical formation of ozone and fine mode aerosol. Dimethyl sulphide (DMS), in particular, can also impact cloud formation and the radiative budget as it produces sulfate aerosols upon atmospheric oxidation. Recent studies hav...

We report the first ambient measurements of thirteen VOCs for investigations of emissions and air quality during fog and non-fog wintertime conditions at a tower site (28.57° N, 77.11° E, 220 m amsl) in the megacity of Delhi. Measurements of acetonitrile (biomass burning (BB) tracer), isoprene (biogenic emission tracer in daytime), toluene (a traff...

Post-harvest paddy stubble burning occurs every year in the N.W. Indo Gangetic Plain over a large area during November. This activity emits a large number of gaseous and particulate pollutants into the air and causes severe deterioration in regional air quality. In this paper, we present in-situ measurements of 49 C2-C10 NMHCS (22 alkanes, 11 alken...

Biogenic volatile organic compound (BVOC) emissions such as terpenes from varied tree species are highly reac-tive and when mixed with anthropogenically emitted nitrogen oxides act as strong precursors of secondary pollutants such as ozone and secondary organic aerosol, with consequences also for cloud formation and the regional climate. Mahogany (...

We studied the impact of the odd-even traffic rule (implemented in Delhi during 1-15 January 2016) on primary traffic emissions using measurements of 13 volatile organic compounds, carbon monoxide, carbon dioxide and methane at a strategic arterial road in Delhi (28.57N, 77.11E, 220 m amsl). Whole air samples (n = 27) were collected during the od...

We studied the impact of the odd-even traffic rule (implemented in Delhi during 1-15 January 2016) on primary traffic emissions using measurements of 13 volatile organic compounds, carbon monoxide, carbon dioxide and methane at a strategic arterial road in Delhi (28.57N, 77.11E, 220 m amsl). Whole air samples (n = 27) were collected during the od...

The objectives of the Winter Fog Experiment (WIFEX) over the Indo-Gangetic Plains of India are to develop better now-casting and forecasting of winter fog on various time- and spatial scales. Maximum fog occurrence over northwest India is about 48 days (visibility < 1000 m) per year, and it occurs mostly during the December-February time-period. Th...