Health & safety in welding & allied processes. Sampling of airborne particles & gases in the operator's breathing zone. Sampling of gases Welding, Health & safety requirements, Occupational safety, Welders, Environment (working), Gases, Particulate air pollutants, Sampling methods, Vapours, Ozone, Carbon monoxide, Carbon dioxide, Nitric oxide, Nitrogen dioxide, Arc welding, Gas welding, Metal-arc welding, Gas analysis