Changes in tropospheric composition and air quality

doi:10.1016/S1011-1344(98)00187-0

CORC > 北京大学 > 环境科学与工程学院

	Changes in tropospheric composition and air quality
	Tang, X ; Madronich, S ; Wallington, T ; Calamari, D
刊名	光化学与光生物学杂志 b辑生物学
	1998
关键词	air quality tropospheric composition ultraviolet-B radiation ozone hydroxyl radicals hydrochlorofluorocarbons hydrofluorocarbons ATMOSPHERIC CHEMISTRY TRIFLUOROACETIC-ACID GROWTH-RATE STRATOSPHERIC OZONE HYDROXYL RADICALS HCFC-123 CF3CHCL2 HFC-134A CF3CH2F UV-RADIATION OH RADICALS HYDROCHLOROFLUOROCARBONS
DOI	10.1016/S1011-1344(98)00187-0
英文摘要	Reductions in stratospheric ozone (O-3) cause increased penetration of ultraviolet-B (UV-B) radiation to the troposphere, and therefore increases in the chemical activity in the lower atmosphere (the troposphere). Tropospheric ozone levels are sensitive to local concentrations of nitrogen oxides (NOx) and hydrocarbons. Model studies suggest that additional W-B radiation reduces tropospheric ozone in clean environments (low NOx), and increases tropospheric ozone in polluted areas thigh NOx). Assuming other factors remain constant, additional UV-B will increase the rate at which primary pollutants are removed from the troposphere. Increased UV-B is expected to increase the concentration of hydroxyl radicals (OH) and result in faster removal of pollutants such as carbon monoxide (CO), methane (CH4), nonmethane hydrocarbons (NMHCs), sulfur and nitrogen oxides, hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs). Concentrations of peroxy radicals (both inorganic and organic) are expected to increase, leading to higher atmospheric levels of hydrogen peroxide (H2O2) and organic peroxides. The effects of UV-B increases on tropospheric O-3, OH, methane, CO, and possibly other tropospheric constituents, while not negligible, will be difficult to detect because the concentrations of these species are also influenced by many other variable factors (e.g., emissions). Trifluoroacetic acid (TFA, CF3COOH) is produced in the atmosphere by the degradation of HCFC-123 (CF3CHCl2), HCFC-124 (CF3CHFCl), and HFC-134a (CF3CH2F), which are used as substitutes for ozone-depleting substances. The atmospheric oxidation mechanisms of these replacement compounds are well established. Reported measurements of TFA in rain, rivers, lakes, and oceans show it to be a ubiquitous component of the hydrosphere, present at levels much higher than can be explained by reported sources. The levels of TFA produced by the atmospheric degradation of HFCs and HCFCs emitted up to the year 2020 are estimated to be orders of magnitude below those of concern, and to make only a minor contribution to the current environmental burden of TFA. No significant effects on humans or the environment have been identified from TFA produced by atmospheric degradation of HCFCs and HFCs. Numerous standard short-term studies have shown that TFA has, at most, moderate toxicity. (C) 1998 UNEP. Published by Elsevier Science S.A. All rights reserved.; Biochemistry & Molecular Biology; Biophysics; SCI(E); PubMed; 44; REVIEW; 1-3; 83-95; 46
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/202019]
专题	环境科学与工程学院
推荐引用方式 GB/T 7714	Tang, X,Madronich, S,Wallington, T,et al. Changes in tropospheric composition and air quality[J]. 光化学与光生物学杂志 b辑生物学,1998.
APA	Tang, X,Madronich, S,Wallington, T,&Calamari, D.(1998).Changes in tropospheric composition and air quality.光化学与光生物学杂志 b辑生物学.
MLA	Tang, X,et al."Changes in tropospheric composition and air quality".光化学与光生物学杂志 b辑生物学 (1998).