Theoretical and field evaluation of a PM2.5 high-volume impactor inlet design

Abstract A PM2.5 high-volume impactor (HVI) sampler is developed, which has a flow rate of 1130 L per minute (lpm) (1.13 m3/min) and in it, the filter size used is of 8 inch × 10 inch. The major advantages of this sampler as compared to other low-volume sampler (flow rate 16.67 lpm) are lower uncertainty in mass measurement, higher PM2.5 mass collection and lesser sampling time. To develop this PM2.5 HVI sampler, a series of simulation and experimental studies were carried out. The optimized D50 cutoff size of 2.52 μm was obtained experimentally under real ambient conditions (i.e. with polydisperse ambient particles) after the parametric adjustments. The commercial PM2.5 HV sampler cutoff size was also evaluated experimentally and agreed well to the D50 cutoff size of developed PM2.5 HVI sampler. Field performance studies of developed PM2.5 HVI sampler were also carried out under both high- and low- particle mass loading conditions along with commercial PM2.5 high- and low-volume samplers. The developed PM2.5 HVI sampler agreed well with commercial PM2.5 high- and low-volume samplers, i.e. PM2.5 HVS, BAM and WINS reference sampler in mass measurement with mean deviations of 12.7, 18.5 and 11.7 μg/m3 (i.e. 5.05, 4.86 and 3.70%), respectively under tested conditions. This PM2.5 HVI sampler is very useful especially where the extensive offline chemical analysis of filter samples/high amount of particulate material is needed for source apportionment studies or analysis of bioassay or toxicological purposes (in vitro/in vivo studies), diurnal studies, and air sampling where the mass concentration of particles is very low, e.g. marine, polar regions, most of the rural sites, etc.