Welding is a process of joining metals by melting and fusing. The trade of welding also involves cutting metal objects, grinding, brazing and in some applicators soldering. Welding is an indispensable trade in modern society and is ubiquitous in industry. According to the National Institute of Occupational Safety and Health (NIOSH) in 1988, there are at least 2,000,000 welders in the world . Welding itself consists of a number of complex operations that include exposure to toxic gases (particularly nitrogen dioxide and ozone), metal fumes (Zinc oxide, copper, chromium oxides, nickel), particles (iron), infra red irradiation, ultra violet irradiation, noise and extremes of temperature.Introduction Welding is a process of joining metals by melting and fusing.

The trade of welding also involves cutting metal objects, grinding, brazing and in some applicators soldering. Welding is an indispensable trade in modern society and is ubiquitous in industry. According to the National Institute of Occupational Safety and Health (NIOSH) in 1988, there are at least 2,000,000 welders in the world . Welding itself consists of a number of complex operations that include exposure to toxic gases (particularly nitrogen dioxide and ozone), metal fumes (Zinc oxide, copper, chromium oxides, nickel), particles (iron), infra red irradiation, ultra violet irradiation, noise and extremes of temperature. The particle size distribution of welding fumes is an important factor in determining the hazard potential of the fumes because it is an indication of the depth to which the particles may penetrate into the lungs and the number of particles retained therein.

Studies on welding fumes have shown the particleson welding fumes have shown the particles to be < 0.50 mm in aerodynamic diameter giving them a high probability of being deposited in the respiratory bronchioles and alveoli of the lungs where rapid clearance by the mucociliary system is not effective. Morphologic characterizations of welding fumes have shown that many of the individual particles are in the ultrafine size range (0.01 to 0.10 mm) and had aggregated together in the air to form longer chains of primary

Welding,joining metals, melting and fusing, trade of welding, cutting metal objects, grinding, brazing ,and in some applicators soldering, Welding trade in modern society , National Institute of Occupational Safety, Health (NIOSH) in 2,000,000 welders, world, complex operations.