Field-based Inter-comparison of an Indigenously Designed and Developed off-centric PM2.5 Impactor with a Standardized Impactor

Kaniska Biswas; Prashant Rajput; Avinash Gupta; Arindam Roy; Bishakh Bhattacharya; Tarun Gupta

Authors

Kaniska Biswas Design Program, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
Prashant Rajput Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India | Current address: Centre for Environmental Health, Public Health Foundation of India, Gurugram-122002, Haryana, India
Avinash Gupta Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
Arindam Roy South Asian Forum for Environment, Kolkata - 700099, India
Bishakh Bhattacharya Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India | Center for Cognitive science, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
Tarun Gupta Design Program, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India| Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India

Keywords:

Inertial impactor, PM2.5, Novel off-centric impactor, Reduced particle bounce-off, FE-SEM

Abstract

Inertial impactors can segregate particles based on their inertia difference, although it is associated with an inherent problem of particle bounce-off, which yields errors in the particle collection. Previously we have developed a novel PM2.5 impactor with an off-centric rotating nozzle which has less tendency of particle bounce-off. In this study, we have evaluated the performance of this off-centric impactor by comparing it with a conventional impactor having the same flow rate and same cut-off diameter (PM2.5,15 LPM and sampling time: 24 h) through two sets of experiments. In experiment 1, the off-centric impactor was not rotated, and thus, it mimics like a conventional impactor. In experiment 2, the offcentric impactor was rotated to 90 degrees after each 6 h. For each set of experiments, we gravimetrically compared the filter substrate and the impaction surface from both the impactors. In experiment 2, the off-centric impactor exhibited a higher difference in the collected mass and greater impaction area than that in experiment 1, which is attributable to the reduction of particle bounce-off. We performed FESEM (Field Emission-Scanning Electron Microscope) analysis on the aerosol laden filters, which confirms the cut-off diameter of the novel off-centric to be PM2.5.