Development and Characterization of a Time-Sequenced Cascade Impactor: Application to Transient PM2.5 Pollution Events in Urbanized and Industrialized Environments

Atmosphere

Marie Choël¹  Pascal Flament²  Fabien Marteel²  Soulemane Halif Ngagine²  Karine Deboudt²  Pierre Kulinski² 

[1] Univ. Lille, CNRS, UMR 8516-LASIRE-Laboratoire Avancé de Spectroscopie pour les Interactions, la Réactivité et l’Environnement, F-59000 Lille, France;Univ. Littoral Côte d’Opale, LPCA-Laboratoire de Physico-Chimie de l’Atmosphère, F-59140 Dunkerque, France;

关键词: rotary cascade impactor;    PM_2.5;    collection efficiency;    SEM-EDX;    individual particle analysis;    urban pollution event;   

DOI  :  10.3390/atmos13020244

来源: DOAJ

【 摘 要 】

To set up a sampling and analysis strategy for particulate matter (PM) based on the time periods used in international standards is often inadequate for assessing the impact of day/night cycles or episodic emissions on urban air quality. To obtain a detailed physico–chemical characterization of urban PM when concentrations exceed the regulatory thresholds, a new rotary cascade impactor named the Time-Resolved Atmospheric Particle Sampler (TRAPS) was designed and tested for coarse and fine particle sampling. The TRAPS implementation, coupled with Optical Particle Counter measurements, provides time-resolved samples that can be analyzed by a wide range of single-particle analysis techniques. The TRAPS theoretical design was verified experimentally. Experimental cut-off diameters of 1.32 and 0.13 µm, respectively, for coarse and fine stages, were found in good agreement with theoretical values. Additionally, good trace separation, preventing inter-sample contamination, was evidenced by Scanning Electron Microscopy (SEM). The homogeneous distribution of particles of different types over a trace was also verified. As a case study, automated SEM-EDX analysis of 2500 particles, collected during two pollution peaks of a transient PM_2.5 pollution event, revealed that individual particles’ chemical composition was influenced by local sources during the first pollution peak, and mainly transported during the second peak.

【 授权许可】

Unknown