Biogenic and anthropogenic isoprene emissions in the subtropical urban atmosphere of Delhi

Kashyap, Prabhat; Kumar, Amit; Kumar, Ram; Kumar, Krishan

doi:10.1016/j.apr.2019.07.004

Cited by 28 publications

(7 citation statements)

References 50 publications

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“…A recent study in Delhi averaged across post-monsoon, summer, and winter campaigns found that at vegetative sites biogenic isoprene contributed on average 92 %-96 % to the total isoprene, while at traffic-dominated sites only 30 %-39 % of isoprene was from biogenic sources (Kashyap et al, 2019). This is similar to the contributions of biogenic isoprene (40 %) to total isoprene mixing ratios at the traffic-dominated Marylebone Road London site (Khan et al, 2018a).…”

Section: Isoprene and Monoterpene Measurementssupporting

confidence: 53%

Biogenic and anthropogenic sources of isoprene and monoterpenes and their secondary organic aerosol in Delhi, India

Bryant

Nelson²,

Swift³

et al. 2023

Atmos. Chem. Phys.

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Abstract. Isoprene and monoterpene emissions to the atmosphere are generally dominated by biogenic sources. The oxidation of these compounds can lead to the production of secondary organic aerosol; however the impact of this chemistry in polluted urban settings has been poorly studied. Isoprene and monoterpenes can form secondary organic aerosol (SOA) heterogeneously via anthropogenic–biogenic interactions, resulting in the formation of organosulfate (OS) and nitrooxy-organosulfate (NOS) species. Delhi, India, is one of the most polluted cities in the world, but little is known about the emissions of biogenic volatile organic compounds (VOCs) or the sources of SOA. As part of the DELHI-FLUX project, gas-phase mixing ratios of isoprene and speciated monoterpenes were measured during pre- and post-monsoon measurement campaigns in central Delhi. Nocturnal mixing ratios of the VOCs were substantially higher during the post-monsoon (isoprene: (0.65±0.43) ppbv; limonene: (0.59±0.11) ppbv; α-pinene: (0.13±0.12) ppbv) than the pre-monsoon (isoprene: (0.13±0.18) ppbv; limonene: 0.011±0.025 (ppbv); α-pinene: 0.033±0.009) period. At night, isoprene and monoterpene concentrations correlated strongly with CO during the post-monsoon period. Filter samples of particulate matter less than 2.5 µm in diameter (PM2.5) were collected and the OS and NOS content analysed using ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS2). Inorganic sulfate was shown to facilitate the formation of isoprene OS species across both campaigns. Sulfate contained within OS and NOS species was shown to contribute significantly to the sulfate signal measured via AMS. Strong nocturnal enhancements of NOS species were observed across both campaigns. The total concentration of OS and NOS species contributed an average of (2.0±0.9) % and (1.8±1.4) % to the total oxidized organic aerosol and up to a maximum of 4.2 % and 6.6 % across the pre- and post-monsoon periods, respectively. Overall, this study provides the first molecular-level measurements of SOA derived from isoprene and monoterpene in Delhi and demonstrates that both biogenic and anthropogenic sources of these compounds can be important in urban areas.

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Section: Isoprene and Monoterpene Measurementssupporting

confidence: 53%

Biogenic and anthropogenic sources of isoprene and monoterpenes and their secondary organic aerosol in Delhi, India

Bryant

Nelson²,

Swift³

et al. 2023

Atmos. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…This is potentially due to more stagnant conditions as observed by the VC in Figure S1. 9 A recent study in Delhi averaged across post-monsoon, summer and winter campaigns found that at vegetative sites biogenic isoprene contributed on average 92 -96 % to the total isoprene, while at traffic dominated sites only 30 -39 % of isoprene was from biogenic sources (Kashyap et al, 2019). This is similar to the contributions of biogenic isoprene (40 %) to total isoprene mixing ratios at the traffic dominated Marylebone Road London site.…”

Section: Isoprene and Monoterpene Measurementsmentioning

confidence: 68%

Biogenic and anthropogenic sources of isoprene and monoterpenes and their secondary organic aerosol in Delhi, India

Bryant

Nelson²,

Swift³

et al. 2022

Preprint

View full text Add to dashboard Cite

Abstract. Isoprene and monoterpenes emissions to the atmosphere are generally dominated by biogenic sources. The oxidation of these compounds can lead to the production of secondary organic aerosol, however the impact of this chemistry in polluted urban settings has been poorly studied. Isoprene and monoterpenes can form SOA heterogeneously via anthropogenic-biogenic interactions resulting in the formation of organosulfates (OS) and nitrooxy-organosulfates (NOS). Delhi, India is one of the most polluted cities in the world, but little is known about the emissions of biogenic VOCs or the sources of SOA. As part of the DELHI-FLUX project, gas phase mixing ratios of isoprene and speciated monoterpenes were measured during pre- and post-monsoon measurement campaigns in central Delhi. Nocturnal mixing ratios of the VOCs were substantially higher during the post-monsoon (isoprene: (0.65 ± 0.43) ppbv, limonene: (0.59 ± 0.11) ppbv, α-pinene: (0.13 ± 0.12) ppbv) than the pre-monsoon (isoprene: (0.13 ± 0.18) ppbv, limonene: 0.011 ± 0.025 (ppbv), α-pinene: 0.033 ± 0.009) period. At night, isoprene and monoterpene concentrations correlated strongly with CO across during the post-monsoon period. This is one of the first observations in Asia, suggesting monoterpene emissions are dominated by anthropogenic sources. Filter samples of particulate matter less than 2.5 microns in diameter (PM2.5) were collected and the OS and NOS content analysed using ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC-MS2). Inorganic sulfate was shown to facilitate the formation of isoprene OS species across both campaigns. Sulfate contained within OS and NOS species were shown to contribute significantly to the sulfate signal measured via AMS. Strong nocturnal enhancements of NOS species were observed across both campaigns. The total concentration of OS/NOS species contributed an average of (2.0 ± 0.9) % and (1.8 ± 1.4) % to the total oxidised organic aerosol, and up to a maximum of 4.2 % and 6.6 % across the pre- and post-monsoon periods, respectively. Overall, this study provides the first molecular level measurements of SOA derived from isoprene and monoterpene in Delhi and demonstrates that both biogenic and anthropogenic sources of these compounds can be important in urban areas.

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“…Although it has a relatively high reaction rate with OH radicals, its concentration surged in Summer (1.44 ppb). Given that isoprene is generated from both biogenic and anthropogenic emissions (Kashyap et al, 2019), the respective concentration from the two sources were calculated. A signi cant proportion of biogenic isoprene was the reason why isoprene hardly bore resemblance of seasonal variations to other alkenes.…”

Section: Mixing Ratios Spatio-temporal Characteristics and Chemical C...mentioning

confidence: 99%

VOCs species controlling O3 formation in ambient air and their sources in Kaifeng, China

Chen

Shi

Ren

et al. 2022

Preprint

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The concentration of ozone has been in a rising crescendo in the last decade while the fine particles (PM2.5) is gradually decreasing but still at a high level in central China. Volatile organic compounds (VOCs) are the vital precursors of ozone and PM2.5. A total of 101 VOC species were measured in four seasons at five sites from 2019 to 2021 in Kaifeng. VOC sources and geographic origin of sources were identified by the positive matrix factorization (PMF) model and the HYbrid Single-Particle Lagrangian Integrated Trajectory transport model. The source-specific OH loss rates (LOH) and ozone formation potential (OFP) were calculated to estimate the effects of each VOC source. The average mixing ratios of total VOCs (TVOC) were 43.15 parts per billion (ppb), of which the alkanes, alkenes, aromatics, halocarbons, and oxygenated VOCs respectively accounted for 49%, 12%, 11%, 14%, and 14%. Although the mixing ratios of alkenes were comparatively low, they played a dominant role in the LOH and OFP, especially ethene (0.55 s− 1, 7%; 27.11 µg/m3, 10%) and 1,3-butadiene (0.74 s− 1, 10%; 12.52 µg/m3, 5%). The vehicle-related source which emitted considerable alkenes ranked as the foremost contributing factor (21%). Biomass burning was probably influenced by other cities in the western and southern Henan and other provinces, Shandong and Hebei.

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Biogenic and anthropogenic isoprene emissions in the subtropical urban atmosphere of Delhi

Cited by 28 publications

References 50 publications

Biogenic and anthropogenic sources of isoprene and monoterpenes and their secondary organic aerosol in Delhi, India

Biogenic and anthropogenic sources of isoprene and monoterpenes and their secondary organic aerosol in Delhi, India

Biogenic and anthropogenic sources of isoprene and monoterpenes and their secondary organic aerosol in Delhi, India

VOCs species controlling O3 formation in ambient air and their sources in Kaifeng, China

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