کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4444923 1311261 2005 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The influence of ozone on atmospheric emissions of gaseous elemental mercury and reactive gaseous mercury from substrates
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات علم هواشناسی
پیش نمایش صفحه اول مقاله
The influence of ozone on atmospheric emissions of gaseous elemental mercury and reactive gaseous mercury from substrates
چکیده انگلیسی

Experiments were performed to investigate the effect of ozone (O3) on mercury (Hg) emission from a variety of Hg-bearing substrates. Substrates with Hg(II) as the dominant Hg phase exhibited a 1.7 to 51-fold increase in elemental Hg (Hgo) flux and a 1.3 to 8.6-fold increase in reactive gaseous mercury (RGM) flux in the presence of O3-enriched clean (50 ppb O3; 8 substrates) and ambient air (up to ∼70 ppb O3; 6 substrates), relative to clean air (oxidant and Hg free air). In contrast, Hgo fluxes from two artificially Hgo-amended substrates decreased by more than 75% during exposure to O3-enriched clean air relative to clean air. Reactive gaseous mercury emissions from Hgo-amended substrates increased immediately after exposure to O3 but then decreased rapidly. These experimental results demonstrate that O3 is very important in controlling Hg emissions from substrates. The chemical mechanisms that produced these trends are not known but potentially involve heterogenous reactions between O3, the substrate, and Hg. Our experiments suggest they are not homogenous gas-phase reactions. Comparison of the influence of O3 versus light on increasing Hgo emissions from dry Hg(II)-bearing substrates demonstrated that they have a similar amount of influence although O3 appeared to be slightly more dominant. Experiments using water-saturated substrates showed that the presence of high-substrate moisture content minimizes reactions between atmospheric O3 and substrate-bound Hg. Using conservative calculations developed in this paper, we conclude that because O3 concentrations have roughly doubled in the last 100 years, this could have increased Hgo emissions from terrestrial substrates by 65–72%.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Atmospheric Environment - Volume 39, Issue 39, December 2005, Pages 7506–7517
نویسندگان
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