The relative importance of various pathways for the oxidation of sulfur dioxide and nitrogen dioxide in sunlit continental fair weather clouds

Warneck, Peter

doi:10.1039/a906558j

Cited by 101 publications

(118 citation statements)

References 65 publications

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“…Model simulations suggest that aqueous phase reactions contribute ~two-thirds of the total sulfate production in the troposphere (Warneck, 1999;Unger et al, 2006). Since, ambient temperature is similar during clear days, haze and fog events (Table 1); the higher sulfate formation during haze and fog events can not be fully explained only by the homogeneous gas-phase oxidation of sulphur dioxide.…”

Section: Sulphur and Nitrogen Oxidation Ratios (Sor And Nor)mentioning

confidence: 99%

“…Homogeneous oxidation processes involves the gas-phase reaction of SO 2 with OH radicals and is a temperature dependent process. On the other hand, heterogeneous oxidation reaction of SO 2 can take place on dust aerosol surfaces (Bauer et al, 2004;Krueger et al, 2004), aqueous transformation though catalytic oxidation (via H 2 O 2 /O 3 oxidation in the presence of Mn 2+ and Fe 3+ ) (Martin and Good, 1991;Seinfeld and Pandis, 1998;Tursic et al, 2004) and in-cloud scavenging processes (Warneck, 1999). It has been found that gas phase oxidation is more important prior to fog formation and heterogeneous oxidation take over after fog formation (Rattigan et al, 2001a, b).…”

Section: Sulphur and Nitrogen Oxidation Ratios (Sor And Nor)mentioning

confidence: 99%

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Carbonaceous and Secondary Inorganic Aerosols during Wintertime Fog and Haze over Urban Sites in the Indo-Gangetic Plain

Ram

Sarin

Sudheer

et al. 2012

Aerosol Air Qual. Res.

131

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The chemical composition of total suspended particulate (TSP) matter and secondary aerosol formation have been studied during wintertime fog and haze events from urban sites (Allahabad and Hisar) in the Indo-Gangetic Plain. The atmospheric abundances of elemental carbon (EC), organic carbon (OC), water-soluble OC (WSOC) suggest that organic matter is a major component of TSP, followed by concentrations of sulphate and nitrate under varying meteorological conditions. The concentrations of EC, OC, and WSOC show a nearly 30% increase during fog and haze events at Allahabad and a marginal increase at Hisar; whereas inorganic constituents (NH 4 + , NO 3 − and SO 4 2− ) are 2-3 times higher than those during clear days at both the locations. The sulphur and nitrogen oxidation ratios (SOR and NOR) also exhibit significant increases suggesting possible enhancement of secondary formation of SO 4 2− and NO 3 − during fog and haze events. The significant correlation between NH 4 + -SO 4 2− (R 2 = 0.66, n = 61) and an NH 4 + /SO 4 2− equivalent ratio ≥ 1 during fog-haze conditions suggest nearcomplete neutralization of sulphuric acid by ammonia. In contrast, NH 4 + /SO 4 2− equivalent ratios are less than 1 during normal days suggesting an NH 3 -deficient environment and the possible association of SO 4 2− with mineral dust for neutralization. Secondary inorganic aerosol formation and their hygroscopic growth can have significant impact on atmospheric chemistry, air-quality and visibility impairment during fog-haze events over northern India.

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Section: Sulphur and Nitrogen Oxidation Ratios (Sor And Nor)mentioning

confidence: 99%

Section: Sulphur and Nitrogen Oxidation Ratios (Sor And Nor)mentioning

confidence: 99%

Carbonaceous and Secondary Inorganic Aerosols during Wintertime Fog and Haze over Urban Sites in the Indo-Gangetic Plain

Ram

Sarin

Sudheer

et al. 2012

Aerosol Air Qual. Res.

131

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“…Aqueous-phase SO 2 oxidation in clouds is dominated by H 2 O 2 oxidation (Seinfeld and Pandis, 1998;Liang and Jacobson, 1999;Warneck et al, 1999). The H 2 O 2 oxidation reaction proceeds very quickly and is independent of pH.…”

Section: In-cloud Processingmentioning

confidence: 99%

“…Among the secondary formation pathways of sulfate aerosol, in-cloud aqueous oxidation of SO 2 has been established to be the dominant mechanism, contributing 50-80% of the conversion from SO 2 to sulfate in the troposphere, followed by gas-phase photochemical oxidation of SO 2 (Langner and Rodhe, 1991;McHenry and Dennis, 1994;Seinfeld and Pandis, 1998;Warneck, 1999). Heterogeneous oxidation of SO 2 on the solid particle surface or in the liquid surface layer of particles is insignificant in submicron particles (Saxena and Seigneur, 1987;Meng and Seinfeld, 1994;Liang and Jacobson, 1999;Kerminen et al, 2000).…”

Section: Vapor Condensationmentioning

confidence: 99%

Size distributions of elemental carbon in the atmosphere of a coastal urban area in South China: characteristics, evolution processes, and implications for the mixing state

Huang

2008

Atmos. Chem. Phys.

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Abstract. Elemental carbon (EC), as one of the primary light-absorbing components in the atmosphere, has a significant impact on both regional and global climate. The environmental impacts of EC are strongly dependent on its particle size. Little is known about the size distribution characteristics of EC particles in China's ambient environments. We report size distributions of EC particles in the urban area of Shenzhen in Southern China. In our samples, EC was consistently found in two modes, a fine mode and a coarse mode. The majority of EC mass (∼80%) in this coastal metropolitan city resided in particles smaller than 3.2 µm in diameter. The fine mode peaked at around either 0.42 µm or 0.75 µm. While the mode at 0.42 µm could be ascribed to fresh vehicular emissions in the region, the mode at 0.75 µm was likely a result of particle growth from smaller EC particles. We theoretically investigated the particle growth processes that caused the EC particles to grow from 0.42 µm to 0.75 µm in the atmosphere. Our calculations indicate that the EC peak at 0.75 µm was not produced through either coagulation or H 2 SO 4 condensation; both processes are too slow to lead to significant EC growth. Hygroscopic growth was also determined to be insignificant. Instead, addition of sulfate through in-cloud processing was found to cause significant growth of the EC particles and to explain the EC peak at 0.75 µm. We also estimated the mixing state of EC from the EC size distributions. In the droplet size, at least 45-60% of the EC mass in the summer samples and 68% of the EC mass in the winter samples was internally mixed with sulfate as a result of in-cloud processing. This information on EC should be considered in models of the optical properties of aerosols in this Correspondence to: J. Z. Yu (chjianyu@ust.hk) region. Our results also suggest that the in-cloud processing of primary EC particles could increase the light absorbing capacities through mixing EC with sulfate.

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“…This assumption represents a large source of uncertainty because HSO − 3 is the dominant aqueous S(IV) species under typical cloud water pH (2-7) conditions. NO 2 (Lee and Schwartz, 1983), NO 3 (Feingold et al, 2002), and HNO 4 (Dentener et al, 2002;Warneck, 1999) can also oxidize S(IV) in the aqueous phase. Because of the low solubility of NO 2 , S(IV) + NO 2 is expected to be most important in polluted regions where NO 2 concentrations are high.…”

Section: Oxygen Isotopic Composition Of Sulfatementioning

confidence: 99%

The impact of anthropogenic emissions on atmospheric sulfate production pathways, oxidants, and ice core Δ17O(SO42–)

2011

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Abstract. We use a global three-dimensional chemical transport model to quantify the influence of anthropogenic emissions on atmospheric sulfate production mechanisms and oxidant concentrations constrained by observations of the oxygen isotopic composition ( ). Additional model simulations are conducted to explore the sensitivity of the oxygen isotopic composition of sulfate to uncertainties in the preindustrial emissions of oxidant precursors.

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The relative importance of various pathways for the oxidation of sulfur dioxide and nitrogen dioxide in sunlit continental fair weather clouds

Cited by 101 publications

References 65 publications

Carbonaceous and Secondary Inorganic Aerosols during Wintertime Fog and Haze over Urban Sites in the Indo-Gangetic Plain

Carbonaceous and Secondary Inorganic Aerosols during Wintertime Fog and Haze over Urban Sites in the Indo-Gangetic Plain

Size distributions of elemental carbon in the atmosphere of a coastal urban area in South China: characteristics, evolution processes, and implications for the mixing state

The impact of anthropogenic emissions on atmospheric sulfate production pathways, oxidants, and ice core Δ<sup>17</sup>O(SO<sub>4</sub><sup>2–</sup>)

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The relative importance of various pathways for the oxidation of sulfur dioxide and nitrogen dioxide in sunlit continental fair weather clouds

Cited by 101 publications

References 65 publications

Carbonaceous and Secondary Inorganic Aerosols during Wintertime Fog and Haze over Urban Sites in the Indo-Gangetic Plain

Carbonaceous and Secondary Inorganic Aerosols during Wintertime Fog and Haze over Urban Sites in the Indo-Gangetic Plain

Size distributions of elemental carbon in the atmosphere of a coastal urban area in South China: characteristics, evolution processes, and implications for the mixing state

The impact of anthropogenic emissions on atmospheric sulfate production pathways, oxidants, and ice core Δ&lt;sup&gt;17&lt;/sup&gt;O(SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2–&lt;/sup&gt;)

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The impact of anthropogenic emissions on atmospheric sulfate production pathways, oxidants, and ice core Δ<sup>17</sup>O(SO<sub>4</sub><sup>2–</sup>)