Estimations of primary and secondary organic carbon formation in PM2.5 aerosols of Santiago City, Chile

Seguel, Rodrigo; Morales, Gladys; Leiva, A G Manuel

doi:10.1016/j.atmosenv.2009.01.029

Cited by 45 publications

(38 citation statements)

References 36 publications

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“…As a result of these physical conditions, the resulting airborne particulate matter levels have been recognised as a major pollutant, and the Environmental National Commission, today known as the Environmental Ministry, declared the city PM 10 -saturated in 2004. Additionally, high concentrations of PM 2.5 , over 50% of the total PM 10 , have been reported (Seguel et al, 2009). This study supports the hypothesis that there is a significant contribution of secondary particulates as important constituents of PM 2.5 and that there is a critical need to identify these constituents.…”

Section: Introductionsupporting

confidence: 77%

Urban Atmospheric Ammonia in Santiago City, Chile

Toro

Canales

Flocchini

et al. 2014

Aerosol Air Qual. Res.

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To improve the current understanding of the ammonia distribution in the major urban area of Chile, measurements of atmospheric NH 3 were collected in Santiago during three sampling periods (25 April to 27 May, 11 to 26 June and 27 June to 31 July 2008). Additionally, air quality and meteorological data as well as NH 4 + , NO 3 -, SO 4 = and Ca +2 concentrations in fine particles were collected during the same period. NH 3 concentrations for the different sites in the three sampling periods varied from 7.7 ± 2.0 µg/m 3 to 19.8 ± 2.1 µg/m 3 . The results of one-way ANOVA and cluster analysis suggest that were no significant differences between the three sampling periods, but significant differences in NH 3 concentrations were detected between the sampling sites. Furthermore, two clusters were found with a pronounced difference between sampling sites located in the eastern part of the city and those located in the western part of the city. The results suggest that the distribution of ammonia in the western part of the city is due to the emissions of ammonia by agricultural areas, wetlands and the large sewage treatment plants, while in the eastern part of the city, ammonia emissions are governed by vehicular emissions. Fine particles (PM 2.5 ) chemical speciation showed NH 4 + /SO 4 = and NO 3 -/SO 4 = molar-equivalents ratios of 5.7 ± 0.3 and 1.8 ± 0.1, respectively. The results show that during the sampling period, complete neutralisation of H 2 SO 4 and HNO 3 occurred in the presence of excess of NH 4 + and NH 3 . Therefore, the atmosphere of Santiago can be considered to be ammonia-rich in the gas phase. Abundant NH 3 was present to neutralise the acid components, such as H 2 SO 4 and HNO 3 , and to form fine particulate ammonium salts, such as (NH 4 ) 2 SO 4 , NH 4 NO 3 and others. Relatively high humidity and low temperatures in the cold season support the formation of particulate ammonium nitrate.

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Section: Introductionsupporting

confidence: 77%

Urban Atmospheric Ammonia in Santiago City, Chile

Toro

Canales

Flocchini

et al. 2014

Aerosol Air Qual. Res.

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“…On average the aerosol is composed mainly of organics (59%), followed by nitrate, ammonium, sulfate, chloride and black carbon with 14, 12, 8, 3 and 3%, respectively. This organic fraction is about three times larger than the fraction reported by Seguel et al (2009), and at least two reasons are presented here.…”

Section: Meteorology and Chemical Composition Of Fine Particlesmentioning

confidence: 42%

“…Santiago de Chile presents a persistent valley-mountain breeze system with anticyclonic meteorological conditions throughout the year, which leads to frequent air subsidence and thermal atmospheric inversions all year long. Therefore, aerosol concentrations in Santiago de Chile are strongly influenced by the meteorological and complex topographic conditions (Jorquera et al, 2004;Muñoz, 2005;Morales, 2006;Seguel et al, 2009). For that reason aerosol concentrations are much higher during the beginning of the campaign compared to the end.…”

Section: Meteorology and Chemical Composition Of Fine Particlesmentioning

confidence: 99%

“…Second, the two studies report averages in different times of the year. Seguel et al (2009) reported an average for the summer month of February 2004. In addition, artifacts such as losses due to evaporation of semi volatiles are expected to be larger during summer conditions.…”

Section: Aerosol Chemical Compositionmentioning

confidence: 99%

“…In general, OA can be divided into primary and secondary OA (POA and SOA, respectively). Seguel et al (2009) estimated that the contribution of SOA to organic carbon (OC) can reach 20% of total organic aerosol matter in summer in Santiago by applying EC tracer technique (Turpin and Huntzicker, 1991) to real time measurements of organic and elemental carbon. Although this was an important result for Santiago de Chile, this methodology is rather crude and provides no information about the chemical composition of the organic mass fraction.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Chemical Characterization of Submicron Aerosol Particles in Santiago de Chile

Carbone

Saarikoski

Frey

et al. 2013

Aerosol Air Qual. Res.

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High time resolution chemical characterization of submicron particles was carried out in the South American city of Santiago de Chile using the Aerosol Chemical Speciation Monitor (ACSM). The instrumentation operated for 100 days from August 17 th to November 23 rd 2011 in an urban station located inside the University of Santiago de Chile (USACH) campus. In addition, a semi-continuous OC/EC analyzer was also run in parallel with the ACSM for some of this time. Meteorological conditions varied along the studied period due to the transition from winter to spring time. Atmospheric temperature inversions were responsible for hourly average sub-micron particulate matter levels of up to 80 μg/m 3 , especially during the night time. The average submicron particle mass concentration (± standard deviation) for the whole period was 29.8 ± 25 μg/m 3 . Aerosol particles were composed mainly of organics 59%, followed by nitrate, ammonium, sulfate, black carbon and chloride with contributions of 14, 12, 8, 3 and 3%, respectively. Using positive matrix factorization, the organic fraction was divided into four distinct types of organic aerosol representing fresh automobile exhaust, biomass burning, and two oxygenated organic aerosol factors with different oxidation states. The transition from winter to spring was clearly seen in the composition of OA. The emissions from primary sources, such as vehicle and biomass burning, decreased in the period leading to spring, whereas the amount of oxygenated organic aerosol increased over the same time. This study shows that high time resolution measurements of aerosol chemical composition can lead to better characterizations of the evolution and sources of pollutants in an urban atmosphere.

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Pollution and its Impacts on the South American Cryosphere

et al. 2015

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This article is a review of the science goals and activities initiated within the framework of the Pollution and its Impacts on the South American Cryosphere (PISAC) initiative. Air pollution associated with biomass burning and urban emissions affects extensive areas of South America. We focus on black carbon (BC) aerosol and its impacts on air quality, water availability, and climate, with an emphasis on the Andean cryosphere. BC is one of the key short-lived climate pollutants that is a topic of growing interest for near-term mitigation of these issues. Limited scientific evidence indicates that the Andean cryosphere has already responded to climate change with receding glaciers and snow cover, which directly affect water resources, agriculture, and energy production in the Andean region of South America. Despite the paucity of systematic observations along the Andes, a few studies have detected BC on snow and glaciers in the Andes. These, in addition to existing and projected emissions and weather patterns, suggest a possible contribution of BC to the observed retreat of the Andean cryosphere. Here we provide an overview of the current understanding of these issues from scientific and policy perspectives, and propose strategic expansions to the relevant measurement infrastructure in the region.

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Estimations of primary and secondary organic carbon formation in PM2.5 aerosols of Santiago City, Chile

Cited by 45 publications

References 36 publications

Urban Atmospheric Ammonia in Santiago City, Chile

Urban Atmospheric Ammonia in Santiago City, Chile

Chemical Characterization of Submicron Aerosol Particles in Santiago de Chile

Pollution and its Impacts on the South American Cryosphere

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