Kholdebarin Atefeh, Biati Aida, Moattar Faramarz, Shariat Seyed Mahmoud
Department of Natural Resources Engineering-Environment, Graduate Faculty of Environment and Energy, Tehran Science and Research Branch, Islamic Azad University, Tehran, Iran.
Environ Monit Assess. 2015 Feb;187(2):49. doi: 10.1007/s10661-015-4294-z. Epub 2015 Feb 1.
This study was carried out to specify contribution of different sources in PM10 emission in Tehran City using chemical mass balance method. This is the first time that this method is used in Iran. To this end, the metallic elements including V, Ni, As, Pb, Cd, Hg, Mn, Al, Ca, K, Na, Fe, Zn, Sc, and S were sampled on the filters of high-volume sampler installed at four stations in Tehran. Afterward, highly sensitive inductively coupled plasma (ICP-M90; model aurora-Elit) was used to determine concentration of the elements precipitated on the filters. The obtained results were then compared with standard values. According to the results, the concentration of Cd (16.8 ng/m(3)) was higher than the standard level of 5 ng/m(3) at District 16 on November 14th 2012 which is almost three times the permissible limit. None of the elements Pb, Mn, V, and Hg exceeded the permissible limits except for Ni at District 16. Subsequently, the enrichment factor of the elements was calculated to indicate that elements of anthropogenic origins (Zn, S, Ni, and Hg) are highly enriched with respect to crustal composition (Na, Fe, and Ca). Exceedance factor were calculated for elements of each site to show that all study sites were in low-pollution category. Afterward, the contribution of different pollution sources of road dust, vehicles, and industries in emission of outdoor PM10 was investigated through chemical mass balance (CMB) method. According to which, the highest contribution comes from road dust with a share of 95.4 % of the total outdoor PM10 emission in Tehran mainly originated from the wear and friction of car tires with asphalt pavement. High calcium concentration in all districts of the city confirms the claim. Furthermore, transportation, with a significant difference, has a contribution of 4.05 % of total outdoor PM10 released while industries share very little about 0.4 %. In overall, the quality of road pavement could be a determining factor in releasing considerable amount of outdoor PM10 in urban areas.
本研究旨在运用化学质量平衡法确定德黑兰市PM10排放中不同来源的贡献。这是该方法首次在伊朗使用。为此，在德黑兰四个站点安装的大容量采样器的滤膜上采集了包括V、Ni、As、Pb、Cd、Hg、Mn、Al、Ca、K、Na、Fe、Zn、Sc和S在内的金属元素。之后，使用高灵敏度电感耦合等离子体（ICP - M90；型号为aurora - Elit）测定滤膜上沉淀元素的浓度。然后将所得结果与标准值进行比较。结果显示，2012年11月14日第16区的Cd浓度（16.8 ng/m³）高于5 ng/m³的标准水平，几乎是允许限值的三倍。除第16区的Ni外，Pb、Mn、V和Hg等元素均未超过允许限值。随后，计算了元素的富集因子，以表明人为来源的元素（Zn、S、Ni和Hg）相对于地壳成分（Na、Fe和Ca）高度富集。计算了每个站点元素的超标因子，结果表明所有研究站点均属于低污染类别。之后，通过化学质量平衡（CMB）方法研究了道路扬尘、车辆和工业等不同污染源对室外PM10排放的贡献。据此，最大贡献来自道路扬尘，占德黑兰市室外PM10总排放量的95.4%，主要源于汽车轮胎与沥青路面的磨损和摩擦。该市所有区域的高钙浓度证实了这一说法。此外，交通运输的贡献显著不同，占室外PM10总排放量的4.05%，而工业的贡献非常小，约为0.4%。总体而言，道路路面质量可能是城市地区释放大量室外PM10的一个决定性因素。
