In situ ozone production is highly sensitive to volatile organic compounds in Delhi, India

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(17), P. 13609 - 13630

Published: Sept. 13, 2021

Abstract. The Indian megacity of Delhi suffers from some the poorest air quality in world. While ambient NO2 and particulate matter (PM) concentrations have received considerable attention city, high ground-level ozone (O3) are an often overlooked component pollution. O3 can lead to significant ecosystem damage agricultural crop losses, adversely affect human health. During October 2018, speciated non-methane hydrocarbon volatile organic compounds (C2–C13), oxygenated (o-VOCs), NO, NO2, HONO, CO, SO2, O3, photolysis rates, were continuously measured at urban site Old Delhi. These observations used constrain a detailed chemical box model utilising Master Chemical Mechanism v3.3.1. VOCs NOx (NO + NO2) varied test their impact on local production P(O3), which revealed VOC-limited regime. When only reduced, increase P(O3) was observed; thus, VOC co-reduction approaches must also be considered pollution abatement strategies. Of examined this work, mean morning rates most sensitive monoaromatic compounds, followed by monoterpenes alkenes, where halving led 15.6 %, 13.1 12.9 % reduction respectively. not direct changes aerosol surface area but very may influenced future PM concentrations. divided into emission source sectors, as described Emissions Database for Global Atmospheric Research (EDGAR) v5.0 Air Pollutant EDGAR v4.3.2_VOC_spec inventories, allowing individual sources investigated. Reducing road transport emissions only, common strategy strategies worldwide, found even when removed its entirety. Effective achieved reducing along with combustion manufacturing process emissions. Modelled reduced ∼ 20 ppb h−1 these combined halved. This study highlights importance parallel

Language: Английский

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Emissions of intermediate-volatility and semi-volatile organic compounds from domestic fuels used in Delhi, India

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(4), P. 2407 - 2426

Published: Feb. 18, 2021

Abstract. Biomass burning emits significant quantities of intermediate-volatility and semi-volatile organic compounds (I/SVOCs) in a complex mixture, probably containing many thousands chemical species. These components are significantly more toxic have poorly understood chemistry compared to volatile routinely quantified ambient air; however, analysis I/SVOCs presents difficult analytical challenge. The gases particles emitted during the test combustion range domestic solid fuels collected from across Delhi were sampled analysed. Organic aerosol was onto Teflon (PTFE) filters, residual low-volatility adsorbed surface solid-phase extraction (SPE) discs. A new method relying on accelerated solvent (ASE) coupled comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC × GC–ToF-MS) developed. This highly sensitive powerful technique enabled over 3000 peaks I/SVOC species unique spectra be detected. total 15 %–100 % gas-phase emissions 7 particle-phase characterised. analysed for suitability make quantitative measurements using SPE Analysis discs indicated phenolic furanic important levoglucosan phase. Gas- emission factors 21 polycyclic aromatic hydrocarbons (PAHs) derived, including 16 listed by US EPA as priority pollutants. Gas-phase dominated smaller PAHs. measured (mg kg−1) PAHs cow dung cake (615), municipal waste (1022), crop residue (747), sawdust (1236), fuelwood (247), charcoal (151) liquefied petroleum (56). results this study indicate that likely PAH sources, further is required quantify their impact alongside burning.

Language: Английский

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Relevance and Reliability of Outdoor SO2 Monitoring in Low-Income Countries Using Low-Cost Sensors

Atmosphere, Journal Year: 2023, Volume and Issue: 14(6), P. 912 - 912

Published: May 23, 2023

In the Western world, SO2 concentration in ambient air dropped to low levels, but some emission sources (e.g., merchant ships) and regions low-income countries) still emit substantial amounts of SO2. At those locations, monitoring is critical. However, countries do not have much access expensive reference instruments. Low-cost gas sensors might be an alternative, it unclear how reliable such measurements are. To evaluate performance low-cost same sensor has been subjected three different calibration methods: (1) performed tropical climate Cuba; (2) high-end Belgium; (3) a field at quality measuring station Belgium. The first two methods showed similar trends, suggesting that can calibrated with method. was hampered by concentrations. For campaign Cienfuegos, Cuba, method appeared sufficiently reliable. reliability increases increase concentration, so used Cuba instead

Language: Английский

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

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(1), P. 61 - 83

Published: Jan. 3, 2023

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

Language: Английский

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Obscured Contribution of Oxygenated Intermediate-Volatility Organic Compounds to Secondary Organic Aerosol Formation from Gasoline Vehicle Emissions

Environmental Science & Technology, Journal Year: 2024, Volume and Issue: 58(24), P. 10652 - 10663

Published: June 3, 2024

Secondary organic aerosol (SOA) formation from gasoline vehicles spanning a wide range of emission types was investigated using an oxidation flow reactor (OFR) by conducting chassis dynamometer tests. Aided advanced mass spectrometric techniques, SOA precursors, including volatile compounds (VOCs) and intermediate/semivolatile (I/SVOCs), were comprehensively characterized. The reconstructed produced the speciated VOCs I/SVOCs can explain 69% measured downstream OFR upon 0.5–3 days' OH exposure. While only 10% total production, contribution is 59%, with oxygenated (O–I/SVOCs) taking up 20% that contribution. O–I/SVOCs (e.g., benzylic or aliphatic aldehydes ketones), as obscured source, account for 16% nonmethane gas (NMOG) emission. More importantly, improvement in standards, NMOG effectively mitigated 35% China 4 to 6, which predominantly attributed decrease VOCs. Real-time measurements different components well production further reveal current control measures, such advances engine three-way catalytic converter (TWC) are effective reducing "light" precursors (i.e., single-ring aromatics) but not I/SVOC emissions. Our results also highlight greater effects than previously observed urgent need investigation into their origins, i.e., incomplete combustion, lubricating oil, etc., requires improvements real-time molecular-level characterization molecules turn will benefit future design measures.

Language: Английский

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Will open waste burning become India's largest air pollution source?

Environmental Pollution, Journal Year: 2021, Volume and Issue: 292, P. 118310 - 118310

Published: Oct. 7, 2021

Language: Английский

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Importance of Oxidants and Temperature in the Formation of Biogenic Organosulfates and Nitrooxy Organosulfates

ACS Earth and Space Chemistry, Journal Year: 2021, Volume and Issue: 5(9), P. 2291 - 2306

Published: Sept. 6, 2021

Biogenic secondary organic aerosol (BSOA) makes up a significant proportion of aerosol, and its formation chemistry, composition, physical properties can be influenced by anthropogenic emissions, especially in urban areas. Organosulfates (OSs) are an important class tracers for BSOA have been well-studied over the past decade, although detailed ambient studies diurnal variations still lacking. In this study, fine particulate matter samples were collected eight times day across summer winter campaigns at site Guangzhou, China. Guangzhou is heavily both biogenic allowing biogenic–anthropogenic interactions to studied. Individual OSs nitrooxy (NOSs) species derived from monoterpenes isoprene analyzed using ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC–MS2) quantified three authentic proxy standards. The observations show strong monoterpene NOSs, which peaked during night, with concentrations increasing early evening, highlighting role NO3-oxidation chemistry. Isoprene OSs/NOSs showed seasonal profiles, average 181.8 69.5 ng m–3, respectively, exponential increases observed temperatures above 30 °C. Low-NO pathways dominant summer, while high-NO became more winter. OS was strongly dependent on availability sulfate (SO42–), suggesting extensive heterogeneous chemistry oxidized species. Overall, study provides further insights into biogenically NOS within highly anthropogenically environments.

Language: Английский

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Toward Clean Residential Energy: Challenges and Priorities in Research

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 55(20), P. 13602 - 13613

Published: Oct. 1, 2021

Solid fuels used for cooking, heating, and lighting are major emission sources of many air pollutants, specifically PM2.5 black carbon, resulting in adverse environmental health impacts. At the same time, transition from using residential solid toward cleaner energy can result significant benefits. Here, we briefly review recent research progress on emissions pollutants sector impacts ambient indoor quality, population exposure, consequences. The challenges future priorities identified discussed.

Language: Английский

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Real-time measurements of non-methane volatile organic compounds in the central Indo-Gangetic basin, Lucknow, India: source characterisation and their role in O₃ and secondary organic aerosol formation

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(5), P. 3383 - 3408

Published: March 17, 2023

Abstract. Lucknow is the capital of India's largest state, Uttar Pradesh, one South Asia's most polluted urban cities. Tropospheric photochemistry relies on non-methane volatile organic compounds (NMVOCs), which are ozone and secondary aerosol precursors. Using proton-transfer reaction time-of-flight mass spectrometer (PTR-ToF-MS) at an background site in Lucknow, chemical characterisation NMVOCs was performed real time from December 2020 to May 2021. About ∼ 173 m/z 31.018 197.216 were measured during study period, including aromatics, non-aromatics, oxygenates, nitrogen-containing compounds. The campaign daily mean concentrations 125.5 ± 37.5 ppbv. NMVOC average about 30 % higher winter months (December–February) than summer (March–May). oxygenated aromatics dominant VOC families, accounting for 57 %–80 total concentrations. Acetaldehyde, acetone, acetic acid major species, 5–15 times other species. An advanced multi-linear engine (ME-2) model used perform source apportionment using positive matrix factorisation (PMF). It resolves five main sources contributing these atmosphere. They include traffic (23.5 %), two solid fuel combustion factors, SFC 1 (28.1 %) 2 (13.2 (SVOCs) (18.6 products (VCPs) (16.6 %). Aged fresh emissions (SFCs 2) contributors NMVOCs, related factors had a high (SOA) formation potential. Interestingly, factor second-highest contributor this Significant differences composition combustions indicate influence local transport regional pollution city. temperature leads more volatilisation VOCs, VCP factor. first attempt highlight their contribution pollutant (SOA O3) city summer. insights would help various stakeholders manage primary pollutants within

Language: Английский

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Characteristics of volatile organic compounds (VOCs) at an urban site of Delhi, India: Diurnal and seasonal variation, sources apportionment

Urban Climate, Journal Year: 2023, Volume and Issue: 49, P. 101545 - 101545

Published: April 28, 2023

Language: Английский

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