Real-time characterization and source apportionment of fine particulate matter in the Delhi megacity area during late winter

Lalchandani, Vipul; Kumar, Varun; Tobler, Anna; Thamban, Navaneeth M.; Mishra, Shilpi; Slowik, Jay G.; Bhattu, Deepika; Rai, Pragati; Satish, Rangu; Ganguly, Dilip; Tiwari, Suresh; Rastogi, Neeraj; Tiwari, Shashi; Močnik, Griša; Prévôt, Andrê S. H.; Tripathi, Sachchida Nand

doi:10.1016/j.scitotenv.2021.145324

Cited by 48 publications

(88 citation statements)

References 80 publications

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“…Another possible source of chloride is from the annual crop burning that occurs during the post-monsoon period. It is well known that wood burning is a strong source of particulate KCl (Li et al, 2003;Lanz et al, 2008;Weimer et al, 2008), and while KCl itself is not quantifiable by the AMS, it goes on to form NH 4 Cl via the intermediate reaction of HCl with NH 3 (Sullivan et al, 2007;Wang et al, 2017). SVB-BOA has a strong correlation with chloride (Fig.…”

Section: Sources Of Chloridementioning

confidence: 98%

“…S17). There are many studies which support this conclusion and show crop residue burning to be a significant source of chloride (Li et al, 2003;Sullivan et al, 2007;Lanz et al, 2008;Weimer et al, 2008;Christian et al, 2010;Wang et al, 2017). However, how much of this association is down to the PMF algorithm resolving similarities in thermodynamics and thus reflect the volatile nature of both components is uncertain.…”

Section: Sources Of Chloridementioning

confidence: 99%

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Seasonal analysis of submicron aerosol in Old Delhi using high-resolution aerosol mass spectrometry: chemical characterisation, source apportionment and new marker identification

et al. 2021

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Abstract. We present the first real-time composition of submicron particulate matter (PM1) in Old Delhi using high-resolution aerosol mass spectrometry (HR-AMS). Old Delhi is one of the most polluted locations in the world, and PM1 concentrations reached ∼ 750 µg m−3 during the most polluted period, the post-monsoon period, where PM1 increased by 188 % over the pre-monsoon period. Sulfate contributes the largest inorganic PM1 mass fraction during the pre-monsoon (24 %) and monsoon (24 %) periods, with nitrate contributing most during the post-monsoon period (8 %). The organics dominate the mass fraction (54 %–68 %) throughout the three periods, and, using positive matrix factorisation (PMF) to perform source apportionment analysis of organic mass, two burning-related factors were found to contribute the most (35 %) to the post-monsoon increase. The first PMF factor, semi-volatility biomass burning organic aerosol (SVBBOA), shows a high correlation with Earth observation fire counts in surrounding states, which links its origin to crop residue burning. The second is a solid fuel OA (SFOA) factor with links to local open burning due to its high composition of polyaromatic hydrocarbons (PAHs) and novel AMS-measured marker species for polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Two traffic factors were resolved: one hydrocarbon-like OA (HOA) factor and another nitrogen-rich HOA (NHOA) factor. The N compounds within NHOA were mainly nitrile species which have not previously been identified within AMS measurements. Their PAH composition suggests that NHOA is linked to diesel and HOA to compressed natural gas and petrol. These factors combined make the largest relative contribution to primary PM1 mass during the pre-monsoon and monsoon periods while contributing the second highest in the post-monsoon period. A cooking OA (COA) factor shows strong links to the secondary factor, semi-volatility oxygenated OA (SVOOA). Correlations with co-located volatile organic compound (VOC) measurements and AMS-measured organic nitrogen oxides (OrgNO) suggest SVOOA is formed from aged COA. It is also found that a significant increase in chloride concentrations (522 %) from pre-monsoon to post-monsoon correlates well with SVBBOA and SFOA, suggesting that crop residue burning and open waste burning are responsible. A reduction in traffic emissions would effectively reduce concentrations across most of the year. In order to reduce the post-monsoon peak, sources such as funeral pyres, solid waste burning and crop residue burning should be considered when developing new air quality policy.

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Section: Sources Of Chloridementioning

confidence: 98%

Section: Sources Of Chloridementioning

confidence: 99%

Seasonal analysis of submicron aerosol in Old Delhi using high-resolution aerosol mass spectrometry: chemical characterisation, source apportionment and new marker identification

et al. 2021

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“…, higher peaks in PM 2.5 coincide with north-westerly airmasses sourced to industrial regions in Haryana and Punjab of India all the way back to Lahore in Pakistan and further back to the north-west Lalchandani et al (2021). have shown through high-precision AMS measurements that air mass transport from north-west air over different sites in Delhi is associated with conspicuous amount of highly volatile and semi-volatile OOA.…”

mentioning

confidence: 90%

“…While winter time air pollution over Delhi is studied more frequently because of very high aerosol concentration making them visible and perceptible as a health threat in public mind, concentrations in summer, even though lower than the winter months, are still high enough to pose serious health hazards when exposed for a long time but they are less frequently studied. A campaign-based study during January-March, 2018 over multiple sites in Delhi region using three aerosol mass spectrometers (AMS) for non-refractory fraction, two aethalometers, and one single particle soot photometer concluded that local pollution was dominating over regional pollution during this period (Lalchandani et al, 2021). This was based on the observation of similar chemical composition both within Delhi-NCR and downwind region with mean PM 2.5 reaching 153.8 ± 109.4 μg m −3 with major contribution from organics (43-47%) followed by chloride (11-17%), ammonium (9-13%), sulfate (8-13%), nitrate (9-11%), and (5-16%) black carbon.…”

Section: Aerosolsmentioning

confidence: 99%

Effect of Lockdown on Pollutant Levels in the Delhi Megacity: Role of Local Emission Sources and Chemical Lifetimes

Mallik

Gadhavi

Lal

et al. 2021

Front. Environ. Sci.

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The COVID-19 pandemic resulted in changed emission regimes all over the world. India also imposed complete lockdown on all modes of travel and industrial activities for about 2 months from 25-March-2020 and later unlocked these activities in a phased manner. Here, we study signatures of emissions changes on levels of atmospheric trace gases and aerosols contributing to air pollution over multiple sites in India’s capital Delhi covering various lockdown and unlock phases using satellite data and in-situ observations. The resulting changes in the levels of these species were compared with respect to their average of 2015–2019 to attribute for year to year and seasonal changes. A clear impact of lockdown was observed for AOD, PM, NO2, CO, and SO2 as a result of emission changes, while changed precursor levels led to a change in O3 chemical regimes impacting its concentrations. A detailed analysis of FLEXPART trajectories revealed increased PM levels over Delhi in north-westerly air masses sourced to Punjab region all the way up to Pakistan. Changes in aerosols and NO2 were not only restricted to the surface but transcended the total tropospheric column. The maximum decrease in PM, NO2, CO, and SO2 was observed during the month of total lockdown in April. The lockdown impact varied with species e.g., PM10 and PM2.5 as well as locations even within the periphery of Delhi. While surface level aerosols and NO2 showed significant and almost similar changes, AOD showed much lower decrease than tropospheric column NO2.

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“…The common period in all these studies was between mid-January andmid-March of 2018, which is considered the late winter period. Most importantly, all these studies investigated the chemical composition and source apportionment of fine particulate matter, carbonaceous aerosols, elements in aerosols, and gaseous volatile organic compounds (VOCs) [10][11][12][13][14][15]. More specifically, Tobler et al and Lalchandani et al studied the highly time-resolved chemical characterization of fine particulate matter and source apportionment of organic aerosols and black carbon [10,11].…”

Section: Introductionmentioning

confidence: 99%

Air Pollution in New Delhi during Late Winter: An Overview of a Group of Campaign Studies Focusing on Composition and Sources

et al. 2021

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In recent times, a significant number of studies on the composition and sources of fine particulate matters and volatile organic compounds have been carried out over Delhi, either initiated by or in association with the researchers from the Indian Institute of Technology Kanpur (IIT Kanpur), in collaboration with researchers from within and outside India. All these studies utilized highly time-resolved, campaign-mode observations made with state-of-the-art instrumentation during the late winter months (mid-January to March) of 2018. Individually, each of these studies were rigorous in nature, containing explicit detailing about different types of ambient air pollutants in Delhi such as organic aerosols, inorganic elements, metals, carbonaceous aerosols, and volatile organic compounds. This study consolidates the extremely useful knowledge on source attribution of these air pollutants in the Delhi National Capital Region currently contained in these fragmented studies, which is vital to further enhancing our understanding of composition, characteristics, and sources of air pollutants over Delhi, as well as to designing appropriate mitigation measures tailored to local specifics.

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Real-time characterization and source apportionment of fine particulate matter in the Delhi megacity area during late winter

Cited by 48 publications

References 80 publications

Seasonal analysis of submicron aerosol in Old Delhi using high-resolution aerosol mass spectrometry: chemical characterisation, source apportionment and new marker identification

Seasonal analysis of submicron aerosol in Old Delhi using high-resolution aerosol mass spectrometry: chemical characterisation, source apportionment and new marker identification

Effect of Lockdown on Pollutant Levels in the Delhi Megacity: Role of Local Emission Sources and Chemical Lifetimes

Air Pollution in New Delhi during Late Winter: An Overview of a Group of Campaign Studies Focusing on Composition and Sources

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