Gambaro Andrea, Manodori Laura, Toscano Giuseppa, Contini Daniele, Donateo Antonio, Belosi Franco, Prodi Franco, Cescon Paolo
Environmental Sciences Department, Ca' Foscari University of Venice, 30123 Venice, Italy.
Ann Chim. 2007 May-Jun;97(5-6):343-58. doi: 10.1002/adic.200790020.
The results of an experimental analysis carried out to investigate PM(2.5) concentration levels and the content of polycyclic aromatic hydrocarbons, as well as inorganic trace elements in the atmospheric particles are presented. Measurements were taken with a micrometeorological station equipped with an optical PM(2.5) detector, and simultaneously, particles were collected on filters for subsequent chemical analyses. The average value of daily PM(2.5) concentration is 21.5 ug/m3 and real-time measurements indicate that the average concentration during the day (8 am to 8 pm) is about 25% lower than the nocturnal average. Short-time averages of PM2.5 decrease when the wind speed increases as consequence of the more efficient mixing. Meteorological measurements indicate the presence of a local daily (breeze) circulation with wind blowing from the Alps or the Adriatic Sea and, during this circulation, larger concentrations were observed, with wind coming from the Alps. Days of high PM(2.5) concentration with dominant anthropic or with prevalent crustal contributions were identified. Regarding trace metals, their average concentrations are comparable to those found in others urban areas, except for Cd (3 ng m(-3)), probably due to the presence of glass-works in Murano. The highest concentrations are observed for K (99 ng m(-3)) and Na (73 ng m(-3)), which are the main constituents of marine spray, while the lowest concentrations are observed for elements such as Cs and Co (respectively 0.01 and 0.02 ng m(-3)). Also the concentrations of PAH are comparable with those of other industrial areas, as their sum ranges from 0.16 ng m(-3) to 3.73 ng m(-3), but if considered as B(a)P toxicity equivalent, they are largely lower (0.036 +/- 0.026 ng m(-3)). From the analyses of discriminating ratios, it has been found that the main origin of PAH in PM(2.5) samples may be petrogenic, probably related to the presence of refinery and petrochemical plants on the mainland, although the contribution of combustion processes cannot be excluded.
本文展示了一项实验分析的结果，该分析旨在研究大气颗粒物中PM(2.5)的浓度水平、多环芳烃的含量以及无机微量元素。测量工作由配备光学PM(2.5)探测器的微气象站进行，同时，颗粒物被收集在滤膜上以便后续化学分析。每日PM(2.5)浓度的平均值为21.5微克/立方米，实时测量表明白天（上午8点至晚上8点）的平均浓度比夜间平均值低约25%。由于混合更有效，风速增加时PM2.5的短期平均值会降低。气象测量表明存在局部每日（微风）环流，风从阿尔卑斯山或亚得里亚海吹来，在此环流期间，观察到来自阿尔卑斯山的风导致浓度更高。确定了PM(2.5)浓度高且主要由人为因素或地壳贡献占主导的日子。关于痕量金属，除了镉（3纳克/立方米）外，它们的平均浓度与其他城市地区的浓度相当，这可能是由于穆拉诺岛存在玻璃厂。钾（99纳克/立方米）和钠（73纳克/立方米）的浓度最高，它们是海雾的主要成分，而铯和钴等元素的浓度最低（分别为0.01和0.02纳克/立方米）。多环芳烃的浓度也与其他工业区的浓度相当，其总和范围为0.16纳克/立方米至3.73纳克/立方米，但如果将其视为苯并[a]芘毒性当量，则要低得多（0.036±0.026纳克/立方米）。从判别比分析中发现，PM(2.5)样品中多环芳烃的主要来源可能是成岩作用，可能与大陆上炼油厂和石化厂的存在有关，尽管不能排除燃烧过程的贡献。
