Pollutionwatch: do face masks really prevent the ill effects of pollution?

Scientists tested nine different masks bought from Beijing, with variable resultsWe are all familiar with images of Beijing citizens wearing masks, but do they work? Scientists from Edinburgh’s Institute for Occupational Medicine tested nine different masks bought from Beijing shops. Generally, the filter in each mask worked well, the best stopped over 99% of the particle pollution and the worst stopped 70% to 80%. Next, volunteers wore the masks in a test chamber filled with diesel exhaus