Wearing inexpensive cloth masks in the hope of reducing exposure to air pollution may be of only a little benefit and give you a false sense of security, especially in highly polluted areas, new research suggests. Washable cloth masks are widely used in India and other Asian for personal protection against airborne particulate matter. “Wearing cloth masks reduced the exposure to some extent,” but “the most commonly used cloth mask products perform poorly when compared to alternative options available on the market,” said the study by scientists at University of Massachusetts Amherst. “What became clear to us is that millions of people probably wear these masks and feel safer, but we worry that this is potentially making things worse, if they stand next to a diesel truck and think they are protected by the mask, for example,” said one of the researchers Richard Peltier. In a series of experiments with an experimental mannequin in Nepal, the researchers tested four masks — one pleated surgical type, two cloth and one cone-shaped cloth with exhalation flaps. They tested for several variables and effectiveness in filtering out five different synthetic aerosol particle sizes plus three particle sizes of diluted whole diesel exhaust, which simulated real-world conditions. Among the cloth masks, the one with exhaust valves performed fairly well, removing 80-90 percent of synthetic particles and about 57 per cent of diesel exhaust.