Sources and photodecomposition of formaldehyde and acetaldehyde in Rome ambient air |
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| Institution: | 1. School of Resource and Environmental Sciences, Wuhan University, Wuhan, China;2. Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong;3. Shenzhen Research Institute, Wuhan University, Shenzhen, China;1. Department of Environmental Science and Engineering, Beijing University of Technology, Beijing 100124, China;2. Key Laboratory of Beijing on Regional Air Pollution Control, Beijing 100124, China;3. Center for Satellite Application on Ecology and Environment, Beijing 100094, China |
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| Abstract: | Atmospheric levels of formaldehyde and acetaldehyde as well as their diurnal and seasonal variations were investigated from 1994 to 1997 in downtown Rome during sunny and wind calm days. Hourly concentrations of formaldehyde ranged from 8 to 28 ppbV in summer and 7 to 17 ppbv in winter; acetaldehyde concentrations varied correspondingly within the 3–18 and 2–7 ppbv intervals. Percentages of both aldehydes photochemically produced were estimated through a simple relationship based upon the comparison of individual ratios of formaldehyde and acetaldehyde to toluene in ambient air and automobile emission. Photochemical production was found to weigh upon atmospheric levels for 80–90% in summer days. It dropped below 35% in the winter period, when direct emission from traffic largely predominated. Photochemical summer source was more efficient for acetaldehyde than for formaldehyde, especially in the early morning. The importance of formaldehyde as the major source of hydroxyl radicals in Rome was also assessed. |
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