The influence of humidity, sunlight, and temperature on the daytime decay of polyaromatic hydrocarbons on atmospheric soot particles

Kamens, Richard M.; Guo, Zherui; Fulcher, James N.; Bell, Douglas A.

doi:10.1021/es00166a012

Cited by 286 publications

(183 citation statements)

References 4 publications

(15 reference statements)

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“…The most abundant hydrocarbons residing in greenhouse soils in Beijing suburbs are centered on the 4-, 5-and 6-ring PAHs which are known to be carcinogenic. 34 One plausible explanation is that once deposited in the soil, lower molecular weight PAHs have much higher fluxes by volatilization and condensation, so they tend to evaporate to air or leak into deep soil while higher molecular weight PAHs are relatively less easily losing and then the distribution pattern of PAHs in soil would shift to higher weight PAHs. The other factor effecting the profiles of PAHs in soil may be the different sources.…”

Section: Pahsmentioning

confidence: 99%

Organic contamination in the greenhouse soils from Beijing suburbs, China

Chu

2003

J. Environ. Monitor.

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Selected persistent organic pollutants including HCHs, DDTs and PAHs together with PAEs were determined in the greenhouse soils from Beijing suburbs. The total concentrations were 11.64-29.80 ng g 21 for HCHs, 18.04-101.33 ng g 21 for DDTs, 1.34-3.15 mg g 21 for PAEs and 1.92-7.84 mg g 21 for PAHs, respectively. Predominance of b-HCH in all samples was obviously observed, suggesting a lack of new HCHs sources. High concentrations of DDE and DDD in comparison to their parents in the samples indicated that most of the DDT had been transformed into its metabolites. The contamination of PAHs was relatively serious and the most abundant compounds were 4-, 5-and 6-ring unsubstituted PAHs. The profiles reflect the important effect of traffic on the PAHs remaining in greenhouse soils. Three phthalate esters (DIBP, DnBP and DEHP) accounted for more than 97% of the phthalates studied. Analysis of n-alkanes was also performed in order to trace the natural or anthropogenic sources of hydrocarbons. Characterization and identification of these compounds in greenhouse soil may help in development of strategies to be used in monitoring organic pollutants in this region.

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Section: Pahsmentioning

confidence: 99%

Organic contamination in the greenhouse soils from Beijing suburbs, China

Chu

2003

J. Environ. Monitor.

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“…Therefore, the harmful properties of the atmospheric particulate matter can depend on the probability of thermal and photochemical reactions that transform the parent compounds. Such transformation of PACs may occur via photodegradation on atmospheric particles (Arey et al, 1987;Kamens et al, 1988).…”

Section: Introductionmentioning

confidence: 99%

Light-induced transformations of aza-aromatic pollutants adsorbed on models of atmospheric particulate matter: Acridine and 9(10-H) acridone

Negrón-Encarnación¹,

Arce²

2007

Atmospheric Environment

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The effect of the characteristics of the surface on the phototransformation of acridine, one of the most abundant azapolycyclic compounds encountered in urban atmospheres, and of one of its principal photoproducts, acridone, was studied when adsorbed onto models of the atmospherice particulate matter. For this purpose, relative photodegradation rates were determined from absorption or emission intensities as a function of irradiation times, and some products were isolated and characterized. The relative photodegradation rates of adsorbed acridine show the tendency (NH 4 ) 2 SO 4 > MgO > Al 2 O 3 >SiO 2 . In general, the rates decrease as the fraction of protonated acridine species on the surface increases in MgO, Al 2 O 3 , and SiO 2 , except for (NH 4 ) 2 SO 4 where a fast surface reaction occurs. Oxygen reduces the photodestruction rates by as much as 40 to 60% when compared to an inert atmosphere, implying the participation of an acrideine triplet state in the transformation processes on all surfaces except on (NH 4 ) 2 SO 4 . Acridone, a major product, undergoes a photoinduced tautomerization to 9-hydroxy acridine. The formation of a dihydrodiol, another photoproduct of acridine, is suggested by comparison to reported spectral properties of these compounds. This is formed through a singlet oxygen reaction. Photoproducts showing the absence of the narrow absorption band of 250 nm, characteristic of the π →π* transition in tricyclic aromatics, were detected in small yields but not identified. These results suggest possible photochemical transformation pathways that could lead to the ultimate fate of these pollutants in the environment.

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“…During the 1980s, the Kamens research group investigated the extent to which O 3 , NO 2 , N 2 O 5 and sunlight influence chemical changes of organics on soot particles as these particles age in the atmosphere. [33][34][35] Kamens reported that sunlight [34] promotes the decay of PAH on soot particles as these particles age in the atmosphere, and is more important than oxidation by either O 3 or NO 2 . Guo and Kamens [36] then developed techniques for studying heterogeneous reactions on soot surfaces.…”

Section: Expansion Of the Research Group And Chambers To Test Combustmentioning

confidence: 99%

“…In the mid-1980s from outdoor chamber experiments Kamens and his students were able to develop rate constants for these reactions as a function of sunlight, water vapour and temperature. [34] These rate constants and PAH source signatures were then used in chemical mass balance receptor models to estimate particle source apportionment by student Cheng Kang Li. [39] This rate constant work led to the integration of gas phase smog kinetics with particle PAH and nitro-PAH reactions and permitted the modelling of the daytime formation and decay of selected nitro-PAH (e.g.…”

Section: Expansion Of the Research Group And Chambers To Test Combustmentioning

confidence: 99%

Early history and rationale for outdoor chamber work at the University of North Carolina

2013

Self Cite

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Environmental context. Imagine in 1968 having to tell the largest cities in the US that they would have to spend billions of dollars to reduce human exposure to a gas in their air that no one emitted and that no one knew for sure how it came to be there. This history recalls how scientists and policy makers met this challenge so that by 1985 effective programs were in place.Abstract. The University of North Carolina (UNC) outdoor chamber facility was established in 1972. The chamber produces reliable and interpretable results using ambient sunlight, temperature and weather, providing an effective physical model system for learning about atmospheric chemistry. This article recounts the 40-year history of the chamber facility, from the early days in understanding ozone-precursor relationship to the latest in studying gas and particulate toxicities on human lung cells. PrefaceLike other models, histories are subject to generalisations, distortions and deletions depending upon who is creating the history. We are sure that this history suffers from these operations. Please forgive us in advance if our recollections and mental constructs are somewhat at odds with your own. Perhaps we can have a 'conversation' about this sometime.

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The influence of humidity, sunlight, and temperature on the daytime decay of polyaromatic hydrocarbons on atmospheric soot particles

Cited by 286 publications

References 4 publications

Organic contamination in the greenhouse soils from Beijing suburbs, China

Organic contamination in the greenhouse soils from Beijing suburbs, China

Light-induced transformations of aza-aromatic pollutants adsorbed on models of atmospheric particulate matter: Acridine and 9(10-H) acridone

Early history and rationale for outdoor chamber work at the University of North Carolina

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