Evaluating the efficacy of cloth facemasks in reducing particulate matter exposure

Abstract

Inexpensive cloth masks are widely used in developing countries to protect from particulate pollution albeit limited data on their efficacy exists. This study examined the efficiency of four types of masks (three types of cloth masks and one type of surgical mask) commonly worn in the developing world. Five monodispersed aerosol sphere size (30, 100, and 500 nm, and 1 and 2.5 μm) and diluted whole diesel exhaust was used to assess facemask performance. Among the three cloth mask types, a cloth mask with an exhaust valve performed best with filtration efficiency of 80-90% for the measured polystyrene latex (PSL) particle sizes. Two styles of commercially available fabric masks were the least effective with a filtration efficiency of 39-65% for PSL particles, and they performed better as the particle size increased. When the cloth masks were tested against lab-generated whole diesel particles, the filtration efficiency for three particle sizes (30, 100, and 500 nm) ranged from 15% to 57%. Standard N95 mask performance was used as a control to compare the results with cloth masks, and our results suggest that cloth masks are only marginally beneficial in protecting individuals from particles<2.5 μm. Compared with cloth masks, disposable surgical masks are more effective in reducing particulate exposure.

Facial protection for healthcare workers during pandemics: a scoping review

“…Unfortunately, the material composition of each cloth mask was unknown. 56 The use of surgical sterilisation wrap has been proposed as medical and community groups organise to make improvised masks in light of facial protection shortages. 57 This material is a component of surgical instrument packaging used to maintain sterility.…”

Flattening the curve in COVID-19 using personalised protective equipment: lessons from air pollution

“…Cloth mask performance, although unpredictable in some cases, reduced particles by 57%. 6 In a study in Indonesia, nine different masks were compared. Surgical masks were the only class of mask to significantly decrease PM 2.5 , although they had a large performance range and did not improve PM 2.5 exposure in all subjects.…”

Current understanding on the Effectiveness of Face Masks and Respirators to Prevent the Spread of Respiratory Viruses

“…Also, in cloth face mask the pores are much bigger (figures 2c and d). This arrangement does not provide gradient filtering and explains why cloth face masks have filtering efficiency than surgical face mask [52][53][54] . [52] .…”