Respiratory protection

A dust mask, an N95 mask and an air-purifying respirator with cartridges suit very different exposures, and choosing on comfort alone is a common mistake. Identify the contaminant first, whether particulate, vapour or gas, and its likely concentration; IS 9473 covers respiratory devices, so check the current edition. Specify filter class or cartridge type, half or full face, sizes for fit, and how often filters will need replacing.