scholarly journals Understanding aerosol composition in an inter-Andean valley impacted by sugarcane intensive agriculture and urban emissions

2021 ◽  
Author(s):  
Lady Mateus-Fontecha ◽  
Angela Vargas-Burbano ◽  
Rodrigo Jimenez ◽  
Nestor Y. Rojas ◽  
German Rueda-Saa ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Elemental Carbon ◽  
Water Soluble ◽  
Atmospheric Pollutants ◽  
Diagnostic Ratios ◽  
Aerosol Formation ◽  
Industrial Emissions ◽  
Aerosol Composition ◽  
Secondary Aerosol ◽  
Sampling Campaign

Abstract. Agro-industrial areas are frequently affected by various sources of atmospheric pollutants that negatively impact public health and ecosystems. However, air quality in these areas is infrequently monitored because of their lower population density compared to large cities, especially in developing countries. The Cauca River Valley (CRV) is an agro-industrial region in Southwest Colombia, where a large fraction of the area is devoted to sugarcane and derivatives production. CRV is also affected by road traffic and industrial emissions. This study aims to elucidate the chemical composition of particulate matter fine mode (PM2.5) and to identify the main pollutant sources before source attribution. For this, a sampling campaign was carried out at a representative site of the CRV region, where daily-averaged mass concentrations of PM2.5 and the concentrations of water-soluble ions, trace metals, organic and elemental carbon, and various fractions of organic compounds (carbohydrates, n-alkanes, and polycyclic aromatic hydrocarbons – PAHs) were measured. Mean PM2.5 was 14.38 ± 4.35 ug m−3, and the most abundant constituent was organic material (52.99 % ± 17.79 %), followed by ammonium sulfate (16.12 % ± 3.98 %), and elemental carbon (6.95 % ± 2.52 %), which indicates secondary aerosol formation and incomplete combustion. Levoglucosan was present in all samples with a mean concentration of (113.8 ± 147.2 ng m−3) revealing biomass burning as a persistent source. The diagnostic ratios applied to organic compounds revealed the influence of petrogenic and pyrogenic sources. Principal component analysis identified the influence of traffic-generated road dust, secondary aerosol formation, gasoline and diesel combustion vehicle exhaust, vegetative detritus, and resuspended agriculture soil. However, no single component was dominant nor explained the CRV PM2.5 chemical species variance. Many components had equally important roles instead. Likewise, sugarcane pre-harvest burning, a frequent activity in CRV, was not identified as an independent component. This aerosol and trace gas source contributed to various components and was correlated to the formation of secondary aerosols.

scholarly journals Size-resolved aerosol composition at an urban and a rural site in the Po Valley in summertime: implications for secondary aerosol formation

2016 ◽  
Author(s):  
S. Sandrini ◽  
D. van Pinxteren ◽  
L. Giulianelli ◽  
H. Herrmann ◽  
L. Poulain ◽  
...  
Keyword(s):  
Water Soluble ◽  
Photochemical Oxidation ◽  
Carbonaceous Aerosol ◽  
Rural Site ◽  
Urban Site ◽  
Aerosol Formation ◽  
Aerosol Composition ◽  
Accumulation Mode ◽  
Secondary Aerosol ◽  
Po Valley

Abstract. The aerosol size-segregated chemical composition was analyzed at an urban (Bologna) and a rural site (San Pietro Capofiume) in the Po Valley, Italy, during June and July 2012, to investigate sources and mechanisms of secondary aerosol formation during the summer. A significant enhancement of secondary organic and inorganic aerosol mass was observed under anticyclonic conditions with recirculation of planetary boundary layer air, but with substantial differences between the urban and the rural site. The data analysis, including a Principal Component Analysis (PCA) on the size-resolved dataset of chemical concentrations, indicated that the photochemical oxidation of inorganic and organic gaseous precursors was an important mechanism of secondary aerosol formation at both sites. In addition at the rural site a second formation process, explaining the largest fraction (22 %) of the total variance, was active at night-time, especially under stagnant conditions. Nocturnal chemistry in the rural Po Valley was associated with the formation of ammonium nitrate in large accumulation mode (0.42–1.2 µm) aerosols favored by local thermodynamic conditions (higher relative humidity and lower temperature compared to the urban site). Nocturnal concentrations of fine nitrate were, in fact, on average five times higher at the rural site than in Bologna. The water uptake by this highly hygroscopic compound under high RH conditions provided the medium for increased nocturnal aerosol uptake of water soluble organic gases and possibly also for aqueous chemistry, as revealed by the shifting of peak concentrations of secondary compounds (WSOC and sulfate) toward the large accumulation mode (0.42–1.2 µm). Contrarily, the diurnal production of WSOC (proxy for secondary organic aerosol) by photochemistry was similar at the two sites but mostly affected the small accumulation mode of particles (0.14–0.42 µm) in Bologna, while a shift to larger accumulation mode was observed at the rural site. A significant increment in carbonaceous aerosol concentration (for both WSOC and WINC) at the urban site was recorded mainly in the size range 0.05–0.14 µm indicating a direct influence of traffic emissions on the mass concentrations of quasi-ultrafine particles.

scholarly journals Size-resolved aerosol composition at an urban and a rural site in the Po Valley in summertime: implications for secondary aerosol formation

2016 ◽  
Vol 16 (17) ◽  
pp. 10879-10897 ◽  
Author(s):  
Silvia Sandrini ◽  
Dominik van Pinxteren ◽  
Lara Giulianelli ◽  
Hartmut Herrmann ◽  
Laurent Poulain ◽  
...  
Keyword(s):  
Water Soluble ◽  
Photochemical Oxidation ◽  
Carbonaceous Aerosol ◽  
Rural Site ◽  
Urban Site ◽  
Aerosol Formation ◽  
Aerosol Composition ◽  
Accumulation Mode ◽  
Secondary Aerosol ◽  
Po Valley

Abstract. The aerosol size-segregated chemical composition was analyzed at an urban (Bologna) and a rural (San Pietro Capofiume) site in the Po Valley, Italy, during June and July 2012, by ion-chromatography (major water-soluble ions and organic acids) and evolved gas analysis (total and water-soluble carbon), to investigate sources and mechanisms of secondary aerosol formation during the summer. A significant enhancement of secondary organic and inorganic aerosol mass was observed under anticyclonic conditions with recirculation of planetary boundary layer air but with substantial differences between the urban and the rural site. The data analysis, including a principal component analysis (PCA) on the size-resolved dataset of chemical concentrations, indicated that the photochemical oxidation of inorganic and organic gaseous precursors was an important mechanism of secondary aerosol formation at both sites. In addition, at the rural site a second formation process, explaining the largest fraction (22 %) of the total variance, was active at nighttime, especially under stagnant conditions. Nocturnal chemistry in the rural Po Valley was associated with the formation of ammonium nitrate in large accumulation-mode (0.42–1.2 µm) aerosols favored by local thermodynamic conditions (higher relative humidity and lower temperature compared to the urban site). Nocturnal concentrations of fine nitrate were, in fact, on average 5 times higher at the rural site than in Bologna. The water uptake by this highly hygroscopic compound under high RH conditions provided the medium for increased nocturnal aerosol uptake of water-soluble organic gases and possibly also for aqueous chemistry, as revealed by the shifting of peak concentrations of secondary compounds (water-soluble organic carbon (WSOC) and sulfate) toward the large accumulation mode (0.42–1.2 µm). Contrarily, the diurnal production of WSOC (proxy for secondary organic aerosol) by photochemistry was similar at the two sites but mostly affected the small accumulation mode of particles (0.14–0.42 µm) in Bologna, while a shift to larger accumulation mode was observed at the rural site. A significant increment in carbonaceous aerosol concentration (for both WSOC and water-insoluble carbon) at the urban site was recorded mainly in the quasi-ultrafine fraction (size range 0.05–0.14 µm), indicating a direct influence of traffic emissions on the mass concentrations of this range of particles.

scholarly journals Influence of fuel ethanol content on primary emissions and secondary aerosol formation potential for a modern flex-fuel gasoline vehicle

2016 ◽  
Author(s):  
Hilkka Timonen ◽  
Panu Karjalainen ◽  
Erkka Saukko ◽  
Sanna Saarikoski ◽  
Päivi Aakko-Saksa ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Organic Compounds ◽  
Fuel Ethanol ◽  
Aerosol Formation ◽  
Secondary Aerosol ◽  
Formation Potential ◽  
Aerosol Mass ◽  
Ethanol Content ◽  
Flex Fuel ◽  
Primary Emissions

Abstract. The effect of fuel ethanol content (10 %, 85 %, 100 %) on primary emissions and on subsequent secondary aerosol formation was investigated for a EURO5 flex-fuel gasoline vehicle. Emissions were characterized during the New European Driving Cycle (NEDC) using a comprehensive setup of high time resolution instruments. Detailed chemical composition of exhaust particulate matter (PM) was studied using a soot particle aerosol mass spectrometer (SP-AMS) and secondary aerosol formation using a potential aerosol mass (PAM) chamber. For the primary gaseous compounds, an increase in total hydrocarbon emissions and a decrease of aromatic BTEX (benzene, toluene, ethylbenzene and xylenes) compounds was observed when the amount of ethanol in fuel increased. In regard to particles, largest primary particulate matter concentrations and potential to form secondary particles were measured for the E10 fuel (10 % ethanol). As the ethanol content of the fuel increased, a significant decrease in average primary particulate matter concentrations over the NEDC cycle was found, PM emissions being 0.45, 0.25 and 0.15 mg m−3 for E10, E85 and E100, respectively. Similarly, a clear decrease in secondary aerosol formation potential was observed with larger contribution of ethanol in fuel. Secondary to primary PM ratios were 13.4, and 1.5 for E10 and E85, respectively. For E100 a slight decrease in PM mass was observed after the PAM chamber, indicating that the PM produced by secondary aerosol formation was less than the PM lost via e.g. wall losses or degradation of POA in the chamber. For all fuel blends, the formed secondary aerosol consisted mostly of organic compounds. For E10 the contribution of organic compounds containing oxygen increased from 35 %, measured for primary organics, to 62 % after the PAM chamber. For E85 the contribution of organic compounds containing oxygen increased from 42 % (primary) to 57 % (after the PAM chamber), whereas for E100 the amount of oxidized organics remained the same (approximately 62 %) with the PAM chamber when compared to the primary emissions.

scholarly journals Shipborne measurements of Antarctic submicron organic aerosols: an NMR perspective linking multiple sources and bioregions

2020 ◽  
Vol 20 (7) ◽  
pp. 4193-4207 ◽  
Author(s):  
Stefano Decesari ◽  
Marco Paglione ◽  
Matteo Rinaldi ◽  
Manuel Dall'Osto ◽  
Rafel Simó ◽  
...  
Keyword(s):  
Amino Acids ◽  
Sea Ice ◽  
Organic Compounds ◽  
Coastal Areas ◽  
Weddell Sea ◽  
Water Soluble ◽  
Sea Spray ◽  
Aerosol Composition ◽  
Submicron Aerosol ◽  
Marine Particles

Abstract. The concentrations of submicron aerosol particles in maritime regions around Antarctica are influenced by the extent of sea ice. This effect is two ways: on one side, sea ice regulates the production of particles by sea spray (primary aerosols); on the other side, it hosts complex communities of organisms emitting precursors for secondary particles. Past studies documenting the chemical composition of fine aerosols in Antarctica indicate various potential primary and secondary sources active in coastal areas, in offshore marine regions, and in the sea ice itself. In particular, beside the well-known sources of organic and sulfur material originating from the oxidation of dimethylsulfide (DMS) produced by microalgae, recent findings obtained during the 2015 PEGASO cruise suggest that nitrogen-containing organic compounds are also produced by the microbiota colonizing the marginal ice zone. To complement the aerosol source apportionment performed using online mass spectrometric techniques, here we discuss the outcomes of offline spectroscopic analysis performed by nuclear magnetic resonance (NMR) spectroscopy. In this study we (i) present the composition of ambient aerosols over open-ocean waters across bioregions, and compare it to the composition of (ii) seawater samples and (iii) bubble-bursting aerosols produced in a sea-spray chamber onboard the ship. Our results show that the process of aerosolization in the tank enriches primary marine particles with lipids and sugars while depleting them of free amino acids, providing an explanation for why amino acids occurred only at trace concentrations in the marine aerosol samples analyzed. The analysis of water-soluble organic carbon (WSOC) in ambient submicron aerosol samples shows distinct NMR fingerprints for three bioregions: (1) the open Southern Ocean pelagic environments, in which aerosols are enriched with primary marine particles containing lipids and sugars; (2) sympagic areas in the Weddell Sea, where secondary organic compounds, including methanesulfonic acid and semivolatile amines abound in the aerosol composition; and (3) terrestrial coastal areas, traced by sugars such as sucrose, emitted by land vegetation. Finally, a new biogenic chemical marker, creatinine, was identified in the samples from the Weddell Sea, providing another confirmation of the importance of nitrogen-containing metabolites in Antarctic polar aerosols.

scholarly journals Shipborne measurements of Antarctic submicron organic aerosols: an NMR perspective linking multiple sources and bioregions

2019 ◽  
Author(s):  
Stefano Decesari ◽  
Marco Paglione ◽  
Matteo Rinaldi ◽  
Manuel Dall'Osto ◽  
Rafel Simó ◽  
...  
Keyword(s):  
Sea Ice ◽  
Organic Compounds ◽  
Dimethyl Sulfide ◽  
Coastal Areas ◽  
Weddell Sea ◽  
Water Soluble ◽  
Sea Spray ◽  
Aerosol Composition ◽  
Submicron Aerosol ◽  
Marine Particles

Abstract. The concentrations of submicron aerosol particles in maritime regions around Antarctica are influenced by the extent of sea ice. This effect is two way: on one side, sea ice regulates the production of particles by sea spray (primary aerosols) while, on the other side, it hosts complex communities of organisms emitting precursors for secondary particles. Past studies documenting the chemical composition of fine aerosols in Antarctica indicate various potential primary and secondary sources active in coastal areas, in offshore marine regions as well as in the sea ice itself. In particular, beside the well-known sources of organic and sulfur material originating from the oxidation of dimethyl-sulfide (DMS) produced by microalgae, recent findings obtained during the 2015 PEGASO cruise suggest that nitrogen-containing organic compounds are also produced by the microbiota colonizing the marginal ice zone. To complement the aerosol source apportionment performed using online mass spectrometric techniques, here we discuss the outcomes of offline spectroscopic analysis performed by nuclear magnetic resonance (NMR) spectroscopy. In this study we (i) present the composition of ambient aerosols over open ocean waters across bioregions, and compared it to the composition of (ii) seawater samples and (iii) bubble bursting aerosols produced in a sea spray chamber on board the ship. Our results show that the process of aerosolization in the tank enriches primary marine particles with lipids and sugars while depleting them of free aminoacids, providing an explanation for why aminoacids occurred only at trace concentrations in the marine aerosol samples analyzed. The analysis of water-soluble organic carbon (WSOC) in ambient submicron aerosol samples shows distinct NMR fingerprints for three bioregions: 1) the open Southern Ocean pelagic environments, in which aerosols are enriched with primary marine particles containing lipids and sugars; 2) sympagic areas in the Weddell Sea where secondary organic compounds, including methanesulfonic acid and semivolatile amines abound in the aerosol composition; and 3) terrestrial coastal areas, traced by sugars such as sucrose, emitted by land vegetation. Finally, a new biogenic chemical marker, creatinine, was identified in the samples from the Weddell Sea, providing another confirmation of the importance of nitrogen-containing metabolites in Antarctic polar aerosols.

scholarly journals Sources and oxidative potential of water-soluble humic-like substances (HULIS<sub>WS</sub>) in fine particulate matter (PM<sub>2.5</sub>) in Beijing

2017 ◽  
Author(s):  
Yiqiu Ma ◽  
Yubo Cheng ◽  
Xinghua Qiu ◽  
Gang Cao ◽  
Yanhua Fang ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Biomass Burning ◽  
Fine Particulate Matter ◽  
Waste Incineration ◽  
Water Soluble ◽  
Redox Activity ◽  
Aerosol Formation ◽  
Heating Season ◽  
Secondary Aerosol ◽  
Fine Particulate

Abstract. Water-soluble humic-like substances (HULISWS) are a major redox-active component of ambient fine particulate matter (PM2.5); however, information on their sources and associated redox activity is limited. In this study, total HULISWS, various HULISWS species, and HULISWS-associated dithiothreitol (DTT) activity were quantified in PM2.5 samples collected during a 1-year period in Beijing. Strong correlation was observed between HULISWS and DTT activity; both exhibited higher levels during the heating season than during the non-heating season. Positive matrix factorization analysis of both HULISWS and DTT activity was performed. Four combustion-related sources, namely coal combustion, biomass burning, waste incineration, and vehicle exhaust, and one secondary factor were resolved. In particular, waste incineration was identified as a source of HULISWS for the first time. Biomass burning and secondary aerosol formation were the major contributors (> 59 %) to both HULISWS and associated DTT activity throughout the year. During the non-heating season, secondary aerosol formation was the most important source, whereas during the heating season, the predominant contributor was biomass burning. The four combustion-related sources accounted for > 70 % of HULISWS and DTT activity, implying that future reduction in PM2.5 emissions from combustion activities can substantially reduce the HULISWS burden and their potential health impact in Beijing.

scholarly journals Sources and oxidative potential of water-soluble humic-like substances (HULIS<sub>WS</sub>) in fine particulate matter (PM<sub>2.5</sub>) in Beijing

2018 ◽  
Vol 18 (8) ◽  
pp. 5607-5617 ◽  
Author(s):  
Yiqiu Ma ◽  
Yubo Cheng ◽  
Xinghua Qiu ◽  
Gang Cao ◽  
Yanhua Fang ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Biomass Burning ◽  
Fine Particulate Matter ◽  
Waste Incineration ◽  
Water Soluble ◽  
Redox Activity ◽  
Aerosol Formation ◽  
Heating Season ◽  
Secondary Aerosol ◽  
Fine Particulate

Abstract. Water-soluble humic-like substances (HULISWS) are a major redox-active component of ambient fine particulate matter (PM2.5); however, information on their sources and associated redox activity is limited. In this study, HULISWS mass concentration, various HULISWS species, and dithiothreitol (DTT) activity of HULISWS were quantified in PM2.5 samples collected during a 1-year period in Beijing. Strong correlation was observed between HULISWS and DTT activity; both exhibited higher levels during the heating season than during the nonheating season. Positive matrix factorization analysis of both HULISWS and DTT activity was performed. Four combustion-related sources, namely coal combustion, biomass burning, waste incineration, and vehicle exhausts, and one secondary factor were resolved. In particular, waste incineration was identified as a source of HULISWS for the first time. Biomass burning and secondary aerosol formation were the major contributors (> 59 %) to both HULISWS and associated DTT activity throughout the year. During the nonheating season, secondary aerosol formation was the most important source, whereas during the heating season, the predominant contributor was biomass burning. The four combustion-related sources accounted for > 70 % of HULISWS and DTT activity, implying that future reduction in PM2.5 emissions from combustion activities can substantially reduce the HULISWS burden and their potential health impact in Beijing.

Composition profile of oxygenated organic compounds and inorganic ions in PM2.5 in Hong Kong

2010 ◽  
Vol 7 (4) ◽  
pp. 338 ◽  
Author(s):  
Yun Chun Li ◽  
Jian Zhen Yu
Keyword(s):  
Hong Kong ◽  
Organic Compounds ◽  
Inorganic Ions ◽  
Water Soluble ◽  
Theoretical Studies ◽  
Aerosol Formation ◽  
Oxygenated Compounds ◽  
Hygroscopic Properties ◽  
Synoptic Conditions ◽  
Composition Profiles

Environment context.Oxygenated organic compounds are active constituents in ambient aerosols, affecting their hygroscopic properties and other interactions with water. We have measured 29 oxygenated organic compounds, together with inorganic ions and other major aerosol constituents, in ambient samples collected under various synoptic conditions in Hong Kong. These composition profiles of water-soluble matter provide valuable data for modelling and theoretical studies of aerosol–water interactions. Abstract. This study reports a comprehensive dataset of oxygenated compounds, inorganic ions and other major aerosol constituents in fine particulate matter (2.5 μm) in the urban atmosphere of Hong Kong in periods of different synoptic weather conditions during 2003–05. The oxygenated compounds quantified include C2–C10 dicarboxylic acids, C3–C9 ketoacids and C2–C3 dicarbonyls, their combined concentrations accounting for 3.2–18.2% of water-soluble organic carbon on a carbon mass basis. Six C2 and C3 oxygenated compounds, namely oxalic acid, malonic acid, glyoxylic acid, pyruvic acid, glyoxal, and methyl glyoxal, dominate this suite of oxygenated compounds, accounting for 75% of the total quantified oxygenated species. Good correlations were observed among most of the quantified oxygenated compounds, suggesting that a relatively stable abundance distribution exists under varying synoptic conditions. These composition profiles provide a comprehensive dataset for use in modelling and theoretical studies of aerosol–water interactions, secondary aerosol formation pathways, and speciated organic mass distributions.

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