Design and performance of a novel miniaturized electrostatic sampler for efficient airborne particulate matter sampling

Considering that people spend more than 80% of their time indoors, ambient particulate matter (PM) in the built environment could pose severe environmental health risks to public health. PM sampling, a technique for the enrichment of PM in the air, is essential for ambient PM composition analysis to understand its environmental and health effect. The filtering method that is widely used features a complex post-processing and carries the risk of pore clogging. It is a great challenge to sample airborne PM efficiently for subsequent analysis. Here, we proposed a novel miniaturized electrostatic sampler based on corona discharge and a modified vertically focused electric field for efficient PM sampling. Four intercoupling physical fields in the developed sampler were analyzed, including corona discharge, airflow, particle charging and particle deposition. The collection efficiencies for particles with various sizes (0.01–10 μm) were conducted by simulation and the lowest efficiency occurs at about 0.3–0.5 μm. With an increase in discharging voltage from −6 kV to −9 kV, the lowest efficiency rises from 88.2% to 96.6%. An electrostatic sampler entity was manufactured to test the collection efficiency of PM and the results are in good agreement with the simulation. The induced ring plate can significantly improve the total collection efficiency from 35% to 90% under −6 kV discharging voltage in the experiment. The novel electrostatic sampler exhibits potential and enlightenment for efficient and convenient PM sampling.