Nature and Climate Effects of Individual Tropospheric Aerosol Particles

Pósfai, Mihály; Buseck, Peter R.

doi:10.1146/annurev.earth.031208.100032

Cited by 200 publications

(178 citation statements)

References 156 publications

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“…Due to biomass combustion, the number of soot particles increases significantly, which can be revealed through the enhanced BC mass concentration, as discussed in the next paragraph. Soot pollutants can heat the atmosphere and affect the radiative effect of aerosols on the atmosphere [19,20]. It can be seen from Figure 3c that there was also significant diurnal change in RH before the haze event, but that RH remained at the high level of 60%-70% during the haze event of 11-13 June.…”

Section: Meteorological Conditions and Pollutant Concentrationsmentioning

confidence: 97%

“…Furthermore, atmospheric radiation mechanisms and agricultural activities could also be affected by haze on regional and global scales. Soot particles play the role of an absorbent, which heats the atmosphere and cools the Earth's surface [16][17][18][19][20]. Experts have estimated that regional haze events in China could lead to a 5%-30% decrease in crop yields [21].…”

Section: Introductionmentioning

confidence: 99%

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Aerosol Optical Properties of a Haze Episode in Wuhan Based on Ground-Based and Satellite Observations

Zhang

Gong

et al. 2014

Atmosphere

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A severe haze episode that occurred in Wuhan, central China, from 6-14 June 2012 was investigated using ground-based and satellite-derived observations, from which the optical properties and vertical distribution of the aerosols were obtained. The mass concentrations of PM 2.5 and black carbon (BC) were 9.9 (332.79 versus 33.66 μg·m ). Particle size became larger, consistent with the reduced scattering Ångström exponent. The high asymmetry parameter (0.65) and single scattering albedo (SSA) (0.97) observed in the haze, which coincided with the relatively low backscatter ratio (0.11) and up-scatter fraction (0.23), were related to the increased particle size, and could have had a heating effect on the atmosphere. Aerosols accumulated primarily below 3 km and according to CALIPSO, were regular in their shapes. At the surface, the aerosol extinction coefficient detected by satellite remained at ~1 km , very close to the ground-based observations. Aerosol optical properties measured at this downtown site could help further the understanding of the effects of aerosols on the air quality, city environment, and radiation balance. OPEN ACCESSAtmosphere 2014, 5 700

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Section: Meteorological Conditions and Pollutant Concentrationsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Aerosol Optical Properties of a Haze Episode in Wuhan Based on Ground-Based and Satellite Observations

Zhang

Gong

et al. 2014

Atmosphere

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“…These soot particles were dominated by chain like aggregates of carbon bearing spheres. Various studies have reported that the morphology of carbonaceous particle originated from combustion processes varied from soot chains to complex structures, which depend on fuels, burning conditions and atmospheric processes (Cong et al, 2009;Pósfai and Buseck, 2010;Tumolva et al, 2010). These branched clusters results from the interconnection of often hundred of carbonaceous spherules which stick together through a combination of adhesive surface forces and partial coalescence which occur at high temperature common during combustion (Murr and Bang, 2003).…”

Section: Sem/edx Characterization Of Pm 25 Samplesmentioning

confidence: 99%

Characteristics and Sources of Carbonaceous Aerosols in PM2.5 during Wintertime in Agra, India

Pachauri

Satsangi

Singla

et al. 2013

Aerosol Air Qual. Res.

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PM 2.5 samples were collected at traffic, rural and campus sites in Agra during Nov 2010 to Feb 2011 and characterized for carbonaceous aerosols. The average mass concentrations of PM 2.5 were 308.3 ± 51.8 μg/m 3 , 91.2 ± 17.3 μg/m 3 and 140.8 ± 22.3 μg/m 3 at the traffic, rural and campus sites, respectively. The 24-h mass concentrations of PM 2.5 were significantly higher than the limit of 60 μg/m 3 prescribed in the National Ambient Air Quality Standards (Indian NAAQS) and 25 μg/m 3 of those of the WHO (World Health Organization). The average concentrations of OC (organic carbon) and EC (elemental carbon) were 86.1 ± 5.2 and 19.4 ± 2.4 at the traffic site, 30.3 ± 12.9 and 4.0 ± 1.5 at the rural site and 44.5 ± 18.5 μg/m 3 5.0 ± 1.4 μg/m 3 at the campus one. The contributions of TCA (Total Carbonaceous Aerosol) at the traffic, campus and rural sites were found to be 52, 54 and 58% of PM 2.5 mass, respectively. A significant correlation was observed between water soluble K + and OC at the rural (R 2 = 0.63) and campus (R 2 = 0.53) sites compared to the traffic one (R 2 = 0.35). This may be attributed to increased biomass burning emissions at the rural and campus sites. The concentrations of SOC (Secondary Organic Carbon) were estimated based on the minimum OC/EC ratio, and were found to be 15.3 ± 6.3, 8.2 ± 5.8 and 28.8 ± 15.8 μg/m 3 , accounting for 18, 24.7 and 60.7% of total OC at the traffic, rural and campus sites, respectively. The surface morphology of the particles was analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM/EDX). The results indicated branched chain-like aggregates of carbon bearing spheres at the traffic and rural sites, while at the campus site carbon-rich and minerogenic (mineral dust) particles were the dominant ones.

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“…Therefore, it is important to identify the sources of aerosol particles present in the southeastern United States, as well as their size and mixing state in order to accurately assess their impact on aerosol direct and indirect effects Moise et al, 2015;Posfai and Buseck, 2010). 5 Mixing state is described in terms of external and internal mixtures: an external mixture consists of particles that contain only one pure species per particle, while an internal mixture describes particles that contain equal amounts of all chemical species (Ault and Axson, 2017;Posfai and Buseck, 2010;Riemer and West, 2013). The mixing states of ambient aerosol populations are complex and can vary as a function of size, altitude, and particle age (Fu et al, 2012;Healy et al, 2014a;Moffet et al, 2010b;Pratt 10 and Prather, 2010).…”

Section: Introductionmentioning

confidence: 99%

Diverse Chemical Mixing States of Aerosol Particles in the Southeastern United States

Bondy¹,

Bonanno²,

Moffet³

et al. 2018

Preprint

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Abstract. Aerosols in the atmosphere are chemically complex with thousands or more chemical species distributed in different proportions across individual particles in an aerosol population. An internal mixing 15 assumption, with species present in the same proportions across all aerosols, is used in many models and calculations of secondary organic aerosol (SOA) formation, cloud activation, and aerosol optical properties. However, many of these effects depend on the distribution of species within individual particles, and important information can be lost when internal mixtures are assumed. Herein, we show that during the Southern Oxidant and Aerosol Study (SOAS) in Centreville, Alabama, at a rural, forested 20 location, that aerosols frequently are not purely internally mixed, even in the accumulation mode (0.2-1.0 µm). A range of aerosol sources and mixing states were obtained using computer controlled scanning electron microscopy with energy dispersive X-ray spectroscopy (CCSEM-EDX) and scanning transmission X-ray microscopy-near-edge X-ray absorption fine structure spectroscopy (STXM-NEXAFS). Particles that were dominated by SOA and inorganic salts were the majority of particles by 25 number fraction from 0.2-5 microns with an average of 78% SOA in the accumulation mode. However, during certain periods contributions by sea spray aerosol (SSA) and mineral dust were significant to accumulation (22 % SSA and 26 % dust) and coarse mode number concentrations (38 % SSA and 63% dust). The fraction of particles containing key elements (Na, Mg, K, Ca, and Fe) were determined as a Atmos. Chem. Phys. Discuss., https://doi

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Nature and Climate Effects of Individual Tropospheric Aerosol Particles

Cited by 200 publications

References 156 publications

Aerosol Optical Properties of a Haze Episode in Wuhan Based on Ground-Based and Satellite Observations

Aerosol Optical Properties of a Haze Episode in Wuhan Based on Ground-Based and Satellite Observations

Characteristics and Sources of Carbonaceous Aerosols in PM2.5 during Wintertime in Agra, India

Diverse Chemical Mixing States of Aerosol Particles in the Southeastern United States

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