Istituto di Scienze dell'Atmosfera e del Clima, ISAC-CNR, 73100 Lecce, Italy.
Dipartimento di Beni Culturali, Università del Salento, 73100 Lecce, Italy.
Sci Total Environ. 2018 Jan 15;612:202-213. doi: 10.1016/j.scitotenv.2017.08.230. Epub 2017 Sep 1.
Comparison of fine and coarse fractions in terms of sources and dynamics is scarce in southeast Mediterranean countries; differences are relevant because of the importance of natural sources like sea spray and Saharan dust advection, because most of the monitoring networks are limited to PM. In this work, the main seasonal variabilities of sources and processes involving fine and coarse PM (particulate matter) were studied at the Environmental-Climate Observatory of Lecce (Southern Italy). Simultaneous PM and PM samples were collected between July 2013 and July 2014 and chemically analysed to determine concentrations of several species: OC (organic carbon) and EC (elemental carbon) via thermo-optical analysis, 9 major ions via IC, and 23 metals via ICP-MS. Data was processed through mass closure analysis and Positive Matrix Factorization (PMF) receptor model characterizing seasonal variabilities of nine sources contributions. Organic and inorganic secondary aerosol accounts for 43% of PM and 12% of PM with small seasonal changes. SIA (secondary inorganic aerosol) seasonal pattern is opposite to that of SOC (secondary organic carbon). SOC is larger during the cold period, sulphate (the major contributor to SIA) is larger during summer. Two forms of nitrate were identified: NaNO, correlated with chloride depletion and aging of sea-spray, mainly present in PM; NHNO more abundant in PM. Biomass burning is a relevant source with larger contribution during autumn and winter because of the influence of domestic heating, however, is not negligible in spring and summer, because of the contributions of fires and agricultural practices. Mass closure analysis and PMF results identify two soil sources: crustal associated to long range transport and carbonates associated to local resuspended dust. Both sources contributes to the coarse fraction and have different dynamics with crustal source contributing mainly in high winds from SE conditions and carbonates during high winds from North direction.
在地中海东南部国家，有关细颗粒和粗颗粒在来源和动态方面的比较很少；差异很重要，因为包括海雾和撒哈拉尘埃输送在内的自然来源非常重要，因为大多数监测网络仅限于 PM。在这项工作中，在意大利南部莱切的环境气候观测站研究了细颗粒和粗颗粒（颗粒物）的主要季节性来源和过程变化。在 2013 年 7 月至 2014 年 7 月期间，同时收集了 PM 和 PM 样品，并通过热光分析测定 OC（有机碳）和 EC（元素碳）、IC 测定 9 种主要离子、ICP-MS 测定 23 种金属的浓度。通过质量闭合分析和正矩阵因子化（PMF）受体模型对数据进行处理，该模型描述了九个来源贡献的季节性变化。有机和无机二次气溶胶占 PM 的 43%和 PM 的 12%，季节性变化很小。SIA（二次无机气溶胶）的季节性模式与 SOC（二次有机碳）相反。SOC 在寒冷时期较大，硫酸盐（SIA 的主要贡献者）在夏季较大。确定了两种形式的硝酸盐：NaNO，与氯化物消耗和海雾老化有关，主要存在于 PM 中；NHNO 在 PM 中更为丰富。生物质燃烧是一个重要的来源，由于家庭供暖的影响，秋冬季贡献较大，但在春季和夏季也不容忽视，因为火灾和农业活动的贡献。质量闭合分析和 PMF 结果确定了两个土壤源：与长程传输相关的地壳和与当地再悬浮灰尘相关的碳酸盐。这两个来源都对粗颗粒有贡献，具有不同的动态，地壳源主要在来自东南的大风中贡献，碳酸盐在来自北方的大风中贡献。
