Space and Atmospheric Sciences Division, Physical Research Laboratory, Navrangpura, Ahmedabad, 380 009, India.
Environ Sci Pollut Res Int. 2011 Feb;18(2):212-25. doi: 10.1007/s11356-010-0365-4. Epub 2010 Jul 7.
Inorganic ion concentrations in event-based wet-only precipitation samples collected during the south-west (SW) monsoon at an urban location in Western India, Ahmedabad between July 2000 and September 2002 were measured by Rastogi and Sarin (2007).
For the first time at a location in India, an advanced factor analysis model was retrospectively applied to the measured concentrations of ions (Rastogi and Sarin 2007) in precipitation for source apportionment. Positive matrix factorization resolved five factors, including crustal material, sea salt, nitrate/sulfate-rich factor, ammonium-rich factor, and free acidity.
Amongst the model-resolved factors, crustal material was the highest contributor to the total dissolved solids (TDS) accounting for 44.1% on average. Potential source contribution function (PSCF) analysis identified source locations along the eastern coast of Somalia, Yemen, Oman, and the United Arab Emirates for this factor. Sea salt was the second highest contributor accounting for 29.8%. The potential source regions of this factor were also identified in the Arabian Sea and the southern Indian Ocean along the coast of Africa, and the Arabian Gulf. This study also examined the spatial relationships between the source locations of chemical species in precipitation and in ambient aerosol (resolved in an earlier study).
Crustal material was the highest contributor to TDS at the study location. Spatial relationships between aerosol and precipitation factor source regions suggested that below-cloud scavenging of aerosol particles was a likely contributor to the chemical species apportioned to various precipitation factors. Additionally, source types of chemical species in precipitation resolved in this study were qualitatively compared with those identified at other locations in India. The comparison showed that soil was an important contributor to the dissolved mass of chemical species in precipitation at all locations in India.
拉斯特吉和萨林（2007 年）在印度西部城市艾哈迈达巴德于 2000 年 7 月至 2002 年 9 月西南季风期间收集的基于事件的仅湿降水样本中测量了无机离子浓度。
在印度的一个地点，首次应用了一种先进的因子分析模型来对降水离子浓度（拉斯特吉和萨林，2007 年）进行溯源分析。正矩阵因子化解析出五个因子，包括地壳物质、海盐、富硝酸盐/硫酸盐因子、富铵因子和游离酸度。
在所解析的模型因子中，地壳物质是总溶解固体（TDS）的主要贡献者，平均占 44.1%。潜在源贡献函数（PSCF）分析确定了索马里、也门、阿曼和阿拉伯联合酋长国东海岸的源区。海盐是第二大贡献者，占 29.8%。这个因子的潜在源区也在阿拉伯海和南印度洋沿非洲海岸以及阿拉伯湾被确定。本研究还检查了降水和环境气溶胶中化学物质源区之间的空间关系（在早期研究中解决）。
在研究地点，地壳物质是 TDS 的主要贡献者。气溶胶和降水因子源区之间的空间关系表明，气溶胶颗粒的云下清除可能是分配给各种降水因子的化学物质的重要来源。此外，本研究解析的降水化学物质源类型与印度其他地点确定的源类型进行了定性比较。比较表明，在印度所有地点，土壤都是降水化学物质溶解质量的重要贡献者。
