Chemical characterization of oxygenated organic compounds in the gas phase and particle phase using iodide CIMS with FIGAERO in urban air

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(11), P. 8455 - 8478

Published: June 3, 2021

Abstract. The atmospheric processes under polluted environments involving interactions of anthropogenic pollutants and natural emissions lead to the formation various complex secondary products. Therefore, characterization oxygenated organic compounds in urban areas remains a pivotal issue our understanding evolution carbon. Here, we describe measurements an iodide chemical ionization time-of-flight mass spectrometer installed with Filter Inlet for Gases AEROsols (FIGAERO-I-CIMS) both gas phase particle at site Guangzhou, typical megacity southern China, during autumn 2018. Abundant containing two five oxygen atoms were observed, including acids, multi-functional typically emitted from biomass burning, oxidation products biogenic hydrocarbons aromatics. Photochemistry played dominant roles gaseous acids isoprene-derived nitrates, while nighttime chemistry contributed significantly monoterpene-derived nitrates inorganics. Nitrogen-containing occupied significant fraction total signal phases, elevated fractions higher molecular weights. Measurements by FIGAERO-I-CIMS explained 24 ± 0.8 % aerosol measured (AMS), increased more aged aerosol. systematical interpretation spectra area Guangzhou provides holistic view numerous atmosphere, which can serve as reference future field regions.

Language: Английский

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Influence of intense secondary aerosol formation and long-range transport on aerosol chemistry and properties in the Seoul Metropolitan Area during spring time: results from KORUS-AQ

Atmospheric chemistry and physics, Journal Year: 2018, Volume and Issue: 18(10), P. 7149 - 7168

Published: May 24, 2018

Abstract. Non-refractory submicrometer particulate matter (NR-PM1) was measured in the Seoul Metropolitan Area (SMA), Korea, using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) from 14 April to 15 June 2016, as a part of Korea-US Air Quality Study (KORUS-AQ) campaign. This first highly time-resolved, real-time measurement study springtime SMA and results reveal valuable insights into sources atmospheric processes that contribute PM pollution this region. The average concentration (PM1 = NR-PM1 + black carbon (BC)) 22.1 µg m−3, which composed 44 % organics, 20 sulfate, 17 nitrate, 12 ammonium, 7 BC. Organics had atomic oxygen-to-carbon (O ∕ C) ratio 0.49 organic mass-to-carbon (OM/OC) 1.82. Four distinct OA were identified via positive matrix factorization (PMF) analysis HR-ToF-AMS data: vehicle emissions represented by hydrocarbon-like factor (HOA; O C 0.15; mass), food cooking activities cooking-influenced (COA; 0.19; 22 secondary (SOA) semi-volatile oxygenated (SV-OOA; 0.44; 27 mass) low-volatility (LV-OOA; 0.91; 34 mass). Our indicate air quality during KORUS-AQ influenced strongly formation, with SV-OOA, LV-OOA together accounting for 76 PM1 mass. In particular, formation sulfate mainly promoted elevated ozone concentrations photochemical reactions daytime, whereas SV-OOA nitrate contributed both nocturnal processing VOC nitrogen oxides, respectively, daytime reactions. addition, lower nighttime temperature gas-to-particle partitioning semivolatile species nitrate. During period 4 days (from 23 May ), increased dramatically accounted up 41 intense event associated large enhancements anthropogenic biogenic VOCs (e.g., isoprene toluene), high Ox ( O3 NO2), strong solar radiation, stagnant conditions, suggesting it driven local formation. We have also investigated evolution mechanisms severe haze episodes. Unlike winter events caused coupled meteorological spring appeared be regional factors. For example, there episodes long-range transport plumes followed calm meteorology accumulation species, leading PM. Overall, our pollutants urban Korea originate complex emission composition are controlled various factors, including emissions, upwind sources.

Language: Английский

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Evaluating Organic Aerosol Sources and Evolution with a Combined Molecular Composition and Volatility Framework Using the Filter Inlet for Gases and Aerosols (FIGAERO)

Accounts of Chemical Research, Journal Year: 2020, Volume and Issue: 53(8), P. 1415 - 1426

Published: July 10, 2020

ConspectusThe complex array of sources and transformations organic carbonaceous material that comprises an important fraction atmospheric fine particle mass, known as aerosol, has presented a long running challenge for accurate predictions its abundance, distribution, sensitivity to anthropogenic activities. Uncertainties about changes in aerosol abundance over time translate uncertainties their impact on Earth's climate response air quality policy. One limitation our understanding been lack comprehensive measurements molecular composition volatility, which can elucidate processes affecting abundance. Herein we describe advances the development application Filter Inlet Gases Aerosols (FIGAERO) coupled field-deployable High-Resolution Time-of-Flight Chemical Ionization Mass Spectrometers (HRToF-CIMS). The FIGAERO HRToFCIMS combination broadly probes gas particulate OA by using programmed thermal desorption particles collected Teflon filter with subsequent detection speciation desorbed vapors inherently quantitative selected-ion chemical ionization. provides means obtain insights into volatility components thus physicochemical nature will govern evolution atmosphere.In this Account, discuss design operation FIGAERO, when HRToF-CIMS, characterization molecular-level effective laboratory field. We provide example gleaned from deployment, improve evolution. Specifically, connect profiles equilibrium saturation vapor concentration enthalpy vaporization detected components. also show how HRToF-CIMS environmental simulation chamber experiments field new constraints mechanisms governing secondary formation dynamic associated challenges decomposition during calibration both axis signal. illustrate additional through isothermal evaporation well ultrafine composition. conclude description future opportunities needs ability further science.

Language: Английский

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Restaurant Impacts on Outdoor Air Quality: Elevated Organic Aerosol Mass from Restaurant Cooking with Neighborhood-Scale Plume Extents

Environmental Science & Technology, Journal Year: 2018, Volume and Issue: 52(16), P. 9285 - 9294

Published: Aug. 2, 2018

Organic aerosol (OA) is a major component of fine particulate matter (PM2.5) in urban environments. We performed in-motion ambient sampling from mobile platform with an mass spectrometer (AMS) to investigate the spatial variability and sources OA concentrations Pittsburgh, Pennsylvania, midsize, largely postindustrial American city. To characterize relative importance cooking traffic sources, we sampled some most populated areas (∼18 km2) around Pittsburgh during afternoon rush hour evening mealtime, including congested highways, local roads, high densities restaurants, background locations. found greatly elevated (10s μg m–3) vicinity numerous individual restaurants commercial districts containing multiple restaurants. The AMS spectral information indicates that majority concentration plumes (71%) were sources. Areas both busy roads had systematically higher than only Elevated measured hundreds meters downwind indicating these can influence air quality on neighborhood scales. Approximately 20% population (∼250 000 people) area lives within 200 m restaurant; therefore, restaurant emissions are potentially important source outdoor PM exposures for this large population.

Language: Английский

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Impacts of primary emissions and secondary aerosol formation on air pollution in an urban area of China during the COVID-19 lockdown

Environment International, Journal Year: 2021, Volume and Issue: 150, P. 106426 - 106426

Published: Feb. 9, 2021

Restrictions on human activities were implemented in China to cope with the outbreak of Coronavirus Disease 2019 (COVID-19), providing an opportunity investigate impacts anthropogenic emissions air quality. Intensive real-time measurements made compare primary and secondary aerosol formation Xi'an, before during COVID-19 lockdown. Decreases mass concentrations particulate matter (PM) its components observed lockdown reductions 32–51%. The dominant contributor PM was organic (OA), results a hybrid environmental receptor model indicated OA composed four (POA) factors (hydrocarbon-like (HOA), cooking (COA), biomass burning (BBOA), coal combustion (CCOA)) two oxygenated (OOA) (less-oxidized OOA (LO-OOA) more-oxidized (MO-OOA)). decreased from over range 17% 58%, they affected by control measures processes. Correlations aerosols/ΔCO Ox (NO2 + O3) liquid water content that photochemical oxidation had greater effect nitrate OOAs than sulfate; however, aqueous-phase reaction presented more complex aerosols at different relative humidity condition. efficiencies enhanced as increase atmospheric capacity. Analyses pollution episodes highlighted importance OA, especially LO-OOA, for

Language: Английский

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The importance of size ranges in aerosol instrument intercomparisons: a case study for the Atmospheric Tomography Mission

Atmospheric measurement techniques, Journal Year: 2021, Volume and Issue: 14(5), P. 3631 - 3655

Published: May 20, 2021

Abstract. Aerosol intercomparisons are inherently complex as they convolve instrument-dependent detection efficiencies vs. size (which often change with pressure, temperature, or humidity) and variations in the sampled aerosol population, addition to differences chemical principles (e.g., inorganic-only nitrate inorganic plus organic for two instruments). The NASA Atmospheric Tomography Mission (ATom) spanned four separate aircraft deployments which remote marine troposphere from 86∘ S 82∘ N over different seasons a wide range of concentrations compositions. Aerosols were quantified set carefully characterized calibrated instruments, some based on particle sizing composition measurements. This study aims provide critical evaluation inlet transmissions impacting intercomparisons, quantification during ATom, focus mass spectrometer (AMS). volume determined physical instruments (aerosol microphysical properties, AMP, 2.7 nm 4.8 µm optical diameter) is compared detail that derived measurements AMS single soot photometer (SP2). Special attention was paid characterize upper end size-dependent transmission in-field calibrations, we show be accurate comparisons across inevitably cuts. Observed between campaigns emphasize importance characterizing each instrument field meaningful interpretation comparisons. Good agreement (regression slope =0.949 1.083 ATom-1 ATom-2, respectively; SD =0.003) found composition-based (including AMS-quantified sea salt) AMP after applying transmission. captured, average, 95±15 % standard PM1 (referred URG Corp. cut 1 cyclone operated at its nominal efficiency). These results support absence significant unknown biases appropriateness accuracy estimates total mostly aged air masses encountered ATom. ranges (and their altitude dependence) by complementary (such soluble acidic gases aerosol, SAGA, analysis laser spectrometry, PALMS) investigated inform use future studies.

Language: Английский

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Airborne particulate matter

Philosophical Transactions of the Royal Society A Mathematical Physical and Engineering Sciences, Journal Year: 2020, Volume and Issue: 378(2183), P. 20190319 - 20190319

Published: Sept. 27, 2020

Airborne particulate matter (PM) is a pollutant of concern not only because its adverse effects on human health but ability to reduce visibility and soil buildings materials. It can be regarded as suite pollutants since PM covers very wide range particle sizes also has diverse chemical composition. Historically, much the arose from coal burning was measured black smoke. However, in second half twentieth century developed countries, there reduction smoke emissions steadily became dominated by carbonaceous particles road traffic exhaust secondary pollutants, ammonium salts organic carbon. This exemplified composition fine (referred 2.5 ) London, Delhi Beijing. Steadily, control strategies have addressed more tractable sources emissions, so previously unconventional emerged been seen make significant contribution airborne concentrations. Among these are non-exhaust traffic, cooking aerosol wood The size distribution hugely diverse, ranging newly formed few nanometres diameter through tens micrometres diameter. There great deal interest ultrafine (nano) suspicions enhanced toxicity, decrease source, regional nucleation processes become bigger relative contributors number, mass. article part discussion meeting issue ‘Air quality, past present future’.

Language: Английский

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Real‐Time Characterization of Aerosol Compositions, Sources, and Aging Processes in Guangzhou During PRIDE‐GBA 2018 Campaign

Journal of Geophysical Research Atmospheres, Journal Year: 2021, Volume and Issue: 126(16)

Published: Aug. 6, 2021

Abstract To investigate the chemical compositions, sources, and aging processes of submicron particles (PM 1 ), a comprehensive field campaign was conducted in Guangzhou urban area China during autumn (October–November) 2018. The average mass concentration PM 35.6 ± 20.8 µg m −3 , which mainly contributed by organic aerosols (OA, 42%), then followed sulfate (25%) inorganic nitrate (11%). found to be main driving component (up ∼50%) account for fast increase polluted periods autumn. promotion effects sulfate, aerosol liquid water content, acidity on formation were systematically discussed. Source apportionment results showed 72% OA secondary (SOA), 28% primary (POA), including vehicle emission related hydrocarbon‐like (HOA, 16%), nitrogen‐containing (NOA, 3%) cooking (COA, 8%). explore OA, dynamic variations its oxidation level as function ambient photochemical age are shown. Using an situ field‐deployed flow reactor, heterogeneous reaction rate coefficients POA with OH radicals ( ) estimated 4.0–5.4 × 10 −13 cm 3 molecules −1 s is equivalent lifetime >2 weeks. long supports gas phase major pathway aging. uptake coefficient 0.76–0.84, underlining that can taken up efficiently aerosols.

Language: Английский

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A method for extracting calibrated volatility information from the FIGAERO-HR-ToF-CIMS and its experimental application

Atmospheric measurement techniques, Journal Year: 2019, Volume and Issue: 12(3), P. 1429 - 1439

Published: March 5, 2019

Abstract. The Filter Inlet for Gases and AEROsols (FIGAERO) is an inlet specifically designed to be coupled with the Aerodyne High-Resolution Time-of-Flight Chemical Ionization Mass Spectrometer (HR-ToF-CIMS). FIGAERO-HR-ToF-CIMS provides simultaneous molecular information relating both gas- particle-phase samples has been used extract vapour pressures (VPs) of compounds desorbing from filter whilst giving quantitative concentrations in particle phase. However, such extraction measured components requires use appropriate, well-defined, reference compounds. Vapour homologous series polyethylene glycols (PEG) ((H-(O-CH2-CH2)n-OH) n=3 n=8), covering a range (VP) (10−1 10−7 Pa) that are atmospherically relevant, have shown reproduced well by different techniques, including Knudsen Effusion Spectrometry (KEMS). This first which number pressure measurement techniques found agreement, indicating utility as calibration standard, providing ideal set benchmark accurate characterization FIGAERO extracting chambers real atmosphere. To demonstrate this, single-component mixture measurements made using two instruments based on new determined PEG series. VP values extracted agree those KEMS reported literature, validating this approach data FIGAERO. method then applied chamber measurements, known products estimated.

Language: Английский

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Size-segregated particle number and mass concentrations from different emission sources in urban Beijing

Atmospheric chemistry and physics, Journal Year: 2020, Volume and Issue: 20(21), P. 12721 - 12740

Published: Nov. 4, 2020

Abstract. Although secondary particulate matter is reported to be the main contributor of PM2.5 during haze in Chinese megacities, primary particle emissions also affect concentrations. In order improve estimates contribution sources number and mass concentrations, we performed source apportionment analyses using both chemical fingerprints size distributions measured at same site urban Beijing from April July 2018. Both methods resolved factors related emissions, including vehicular cooking which together make up 76 % 24 total organic aerosol (OA) mass, respectively. Similar types, particles (1.6±1.1 µg m−3; 2.4±1.8×103 cm−3 5.5±2.8×103 for two traffic-related components), (2.6±1.9 m−3 5.5±3.3×103 cm−3) aerosols (51±41 4.2±3.0×103 cm−3), were by methods. Converted concentrations components comparable with those fingerprints. Size distribution separated into a component mode diameter 20 nm (“traffic-ultrafine”) 100 (“traffic-fine”). Consistent similar day- nighttime diesel vehicle estimated area, traffic-fine particles, hydrocarbon-like OA (HOA, factor resulting fingerprints) black carbon (BC) showed diurnal patterns, higher night morning than afternoon when boundary layer higher. Traffic-ultrafine highest rush-hour period, suggesting prominent role local gasoline emissions. absence new formation, our results show that vehicular-related (14 30 ultrafine fine respectively) cooking-activity-related (32 %) dominate concentration, while (over 80 governs non-heating season Beijing.

Language: Английский

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