EFFECTS OF INCREASED SOLAR ULTRAVIOLET-RADIATION ON TROPOSPHERIC   COMPOSITION AND AIR-QUALITY

CORC > 北京大学 > 环境科学与工程学院

	EFFECTS OF INCREASED SOLAR ULTRAVIOLET-RADIATION ON TROPOSPHERIC COMPOSITION AND AIR-QUALITY
	MADRONICH, S ; TANG, XY
刊名	ambio
	1995
关键词	ATMOSPHERIC METHANE HYDROGEN-PEROXIDE OZONE RADICALS H2O2
英文摘要	Reductions of stratospheric ozone and the concomitant increases of UV-B radiation penetrating to the lower atmosphere result in higher photodissociation rates of key trace gases that control the chemical reactivity of the troposphere. This can increase both production and destruction of tropospheric ozone (O-3) and related oxidants such as hydrogen peroxide (H2O2), which are known to have adverse effects on human health, terrestrial plants, and outdoor materials. Changes in the atmospheric concentrations of the hydroxyl radical (OH) may change the atmospheric lifetimes of climatically important gases such as methane (CH4) and the CFC substitutes. Trends in the photodissociation rate coefficient of tropospheric O-3, of about +0.32 +/- 0.04% per year in the Northern Hemisphere and +0.40 +/- 0.05% per year in the Southern Hemisphere, have been estimated from satellite measurements of the ozone column between 1979 and 1992. The corresponding model-calculated changes in tropo-spheric chemical composition are nonlinear and sensitive to the prevailing levels of nitrogen oxides (NOx). In polluted regions (high NOx), tropospheric O-3 is expected to increase, reaching potentially harmful concentrations earlier in the day, and leading to more frequent exceedance of oxidant standards for air quality in urban areas where O-3 levels are routinely near such air quality thresholds. In more pristine regions (lower NOx), O-3 increases can be lower or even negative. Other oxidants, such as H2O2 and OH, are projected to increase for both polluted and pristine regions. Changes to H2O2 concentrations may have some impact on the geographical distribution of acid precipitation. Rural regions may become more urban-like and the percentage of areas with remote tropospheric conditions may decline. Increases in OH concentrations cause a nearly proportionate decrease in the steady-state tropospheric concentrations of CH4 and CFC substitutes such as the HCFCs and HFCs. Thus, the measured reductions in the ozone column (TOMS, 1979-1992) are likely to have moderated CH4 increases over the past decade, and may account for about 1/3 of the slowing of the global CH4 trends. Increased tropospheric reactivity could also lead to changes in the production of particulates such as cloud condensation nuclei, from the oxidation and subsequent nucleation of sulfur of both anthropogenic and natural origin (e.g., carbonyl sulfide and dimethylsulfide). While these processes are still not fully understood, they exemplify the possibility of complex feedbacks between stratospheric ozone reductions, tropospheric chemistry, and climate change.; Engineering, Environmental; Environmental Sciences; SCI(E); 0; ARTICLE; 3; 188-190; 24
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/402956]
专题	环境科学与工程学院
推荐引用方式 GB/T 7714	MADRONICH, S,TANG, XY. EFFECTS OF INCREASED SOLAR ULTRAVIOLET-RADIATION ON TROPOSPHERIC COMPOSITION AND AIR-QUALITY[J]. ambio,1995.
APA	MADRONICH, S,&TANG, XY.(1995).EFFECTS OF INCREASED SOLAR ULTRAVIOLET-RADIATION ON TROPOSPHERIC COMPOSITION AND AIR-QUALITY.ambio.
MLA	MADRONICH, S,et al."EFFECTS OF INCREASED SOLAR ULTRAVIOLET-RADIATION ON TROPOSPHERIC COMPOSITION AND AIR-QUALITY".ambio (1995).