ENVR 154 |
| Mineral aerosol represents a significant fraction of atmospheric primary aerosol. Although only a minor component on a mass basis, TiO2 likely plays a major role in the chemistry of mineral aerosol due to its involvement in photocatalytic processes. Nitrous acid (HONO) is an important atmospheric precursor of hydroxyl radicals and is, therefore, a crucial intermediate in understanding the chemistry of the lower atmosphere (troposphere). There is emerging evidence for photoenhanced heterogeneous HONO production in the troposphere. To this end, we have studied the reactive uptake of NO2 onto TiO2 aerosol under ultraviolet illumination to assess the role of mineral dust aerosol in HONO production. In the absence of illumination no uptake was observed. HONO production was observed and quantified as a function of aerosol substrate and relative humidity in the presence of near-UV light. Further results will be discussed and possible mechanisms proposed. The results highlight a novel daytime source of atmospheric HONO and provide an useful insight into the rate of production of HONO in the presence of mineral dust aerosol. |
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General Papers
6:00 PM-8:00 PM, Wednesday, August 22, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Environmental Chemistry |