Experimental studies on electrostatic-force strengthened particulate matter filtration for built environments: Progress and perspectives

Abstract

Every year, ambient particulate matter (PM) causes more than one million deaths worldwide. Considering that people spend more than 80% of their time indoors, there is an urgent need for efficient air purification in the built environment. Electrostatic forces have been armed with fibrous filters to promote filtration efficiency and avoid large pressure drops leading to large energy consumption, noise problems, and frequent replacements. Here, we summarise the electrostatic-force-strengthened filtration studies with application potentials for indoor PM removal (studies for masks, industrial processes and pollution control are not included), and divide them into three categories according to whether the PM and fibers are charged. Among them, singly-fiber-charged filtration, especially electret filters fabricated by electrospinning, serves in the simplest structure. Synergistically charging both PM and fibers outperforms the singly particle- or fiber-charged filtration, as the PM-fiber Coulombic force is far beyond the dielectrophoresis force. We introduce the working principle for each technology, compare their initial and long-term performance for non-oily particles, oily particles, and bioaerosols, and provide specific research prospects for improving the performance of these technologies.