Laboratoire de Physico-Chimie de l'Atmosphère, Université du Littoral Côte d'Opale, EA 4493-CNRS, 59140 Dunkerque, France.
Département Sciences de l'Atmosphère et Génie de l'Environnement - SAGE, IMT Lille Douai, Université de Lille, 59000 Lille, France.
Sci Total Environ. 2019 Jun 10;668:443-456. doi: 10.1016/j.scitotenv.2019.02.399. Epub 2019 Mar 1.
In a context where a significant fraction of the population lives near industrial areas, the main objectives of this study are to provide (a) new data on PM chemical compositions, heavy-metal concentrations and trace gases released by metalworking activities and (b) new information on the near-field evolution (up to about a thousand meters) of such industrial plumes in terms of particle chemical composition and size distribution. For that purpose, a one-month field campaign was performed in an industrial area near the city of Dunkirk (Northern France), combining measurements of atmospheric dynamics and physico-chemical characterization of air masses. Comparisons between several elemental ratios (mainly Mn/Fe), particle size distributions and volatile organic compound (VOC) concentrations at the stacks and at a near-field site suggest that plumes of a ferromanganese alloy plant were quickly mixed with pollutants emitted by other sources (mainly other industries, possibly traffic and sea spray), in particular a neighboring steelworks, before reaching the sampling site. This led to the emergence of secondary particles related to condensation and/or aggregation phenomena inside the plumes. Metalworking emissions were also identified as a source of new particle formation, formed through the emission of gaseous precursors and their fast transformation and condensation, over a timescale of minutes before reaching the near-field site 800 m downwind. Ultrafine particles emitted at the stacks also quickly agglomerated to form larger particles before reaching the near-field site. These results show that, even over short distances, the chemical composition and size distribution of metalworking plumes may evolve rapidly and the characteristics of particles at the boundary of an industrial area (especially in contiguous urban areas) may differ from those emitted directly at the stacks.
在很大一部分人口居住在工业区附近的情况下，本研究的主要目的是提供（a）金属加工活动释放的 PM 化学成分、重金属浓度和痕量气体的新数据，以及（b）关于此类工业羽流在近场（约 1000 米以内）演变的新信息，包括颗粒化学成分和粒径分布。为此，在敦刻尔克市（法国北部）附近的一个工业区进行了为期一个月的现场测量，结合大气动力学测量和空气团的物理化学特性分析。在烟囱和近场站点测量的几种元素比（主要是 Mn/Fe）、粒径分布和挥发性有机化合物（VOC）浓度之间的比较表明，铁锰合金厂的羽流在到达采样点之前，与其他来源（主要是其他工业、可能是交通和海雾）排放的污染物迅速混合，特别是与附近的钢厂混合。这导致在羽流内部出现与凝结和/或聚集现象有关的二次颗粒。金属加工排放物也被确定为新粒子形成的来源，通过气态前体的排放及其快速转化和凝结形成，在到达近场站点 800m 下风处之前，在几分钟的时间尺度上形成。烟囱排放的超细颗粒也在到达近场站点之前迅速团聚形成较大的颗粒。这些结果表明，即使在短距离内，金属加工羽流的化学成分和粒径分布也可能迅速演变，工业区边界处颗粒的特性（特别是在相邻的城区）可能与直接从烟囱排放的颗粒特性不同。
