How the Atmosphere over Eastern Himalaya, India is Polluted with Carbonyl Compounds? Temporal Variability and Identification of Sources

Abstract

A study was conducted on atmospheric carbonyl compounds for the first time over a Himalayan atmosphere in India. Samples were collected from a high altitude hill station, Darjeeling (27.01°N, 88.15°E, 2200 masl) during June 2012 to May 2013. Temporal variation, meteorological influence, source apportionment and ozone formation potential etc were studied for acetaldehyde, formaldehyde, acetone, butanaldehyde, propanaldehyde, benzaldehyde, crotonaldehyde, valeraldehyde, isovaleraldehyde, hexanaldehyde, p-tolualdehyde and o-tolualdehyde. High concentration of Acetone (81.6 ± 63.5 µg m -3 ) was observed which could be due to the higher photochemical production from its precursor volatile organic compounds emitted from tea plants and tea processing units. The concentration of acetaldehyde (20.7 ± 47.6 µg m ). Meteorological parameters like temperature and surface reaching solar radiative flux played the major roles for the seasonal variation of the carbonyl concentration over the hill station. The average ratio of formaldehyde to acetaldehyde over Darjeeling was found to be 1.64 ± 1.43 well representing a typical urban atmosphere at this part of Himalaya. Positive matrix factorization model showed that the biogenic emissions from tea plants and vehicular emissions were the major sources of carbonyl compounds over the hill station.

Effect of Boundary Layer Evolution on Nitrogen Dioxide (NO2) and Formaldehyde (HCHO) Concentrations at a High-altitude Observatory in Western India

“…In another study Khare et al, (1997b) reported an average 0.8 ± 0.5 ppb (ranging 0.2 -2.8 ppb) HCHO in a semiarid region in northern India, with a peak in the afternoon at ~3-7 pm during February, 1995. Recently Sarkar et al (2017) reported annually averaged HCHO concentrations of 11.6 ± 16.3 µg m -3 (9.5 ± 13.3 ppb)…”

Concentrations of Volatile Organic Compounds in the Megacity of São Paulo in 2006 and 2011/2012 - A Comparative Study

“…Ethanol has low reactivity for ozone formation, however aldehydes are produced in its burning which have high reactivity for O 3 formation, impacting the chemistry of the atmosphere, contributing to the formation of radicals and photochemical processing in the atmosphere (Goldan et al, 2004;de Gouw et al, 2012). Ethanol in the atmosphere is converted into acetaldehyde, a highly reactive compound for ozone formation, which is also toxic to human health (Sarkar et al, 2017). Ethanol was the highest concentration VOCs found in the 2011/2012 campaign, followed by acetaldehyde in this study.…”

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“…These two species have been targeted in numerous toxicological studies owing to their deleterious health effects (Health and Services, 1999; Neghab et al, 2017; Salthammer et al, 2010; Til et al, 1988; Tunsaringkarn et al, 2012b, 2012c). Their ubiquity and importance in ambient air have been documented in many past studies (Lü et al, 2016; Neghab et al, 2017; Sarkar et al, 2017). Owing to rapid global urbanization and population growth, characterizing the concentrations and health effects of these aldehyde species is important as vehicular emissions are a major pollutant source in urban centers (Bauri et al, 2016; Crosbie et al, 2014; Hazrati et al, 2016b; Mannucci and Franchini, 2017; Masih et al, 2016; Morknoy et al, 2011; Rad et al, 2014; Sarkar et al, 2017; Saxena and Ghosh, 2012; Tunsaringkarn et al, 2014).…”