Gas mask protects the wearer from breathing harmful gases or particles into the lungs. The mask fits tightly over the face. Air can enter only through special filter pads that purify and filter the air. Activated charcoal purifies the air by trapping toxic gases and vapors. Particulate filters can remove particles of smoke, dust, and even some harmful biological agents. The purifying materials are in the cheeks of present-day masks, which are often part of an entire protective suit. Older models had a breathing hose attached to a canister.
In World War I (1914-1918), masks were used to protect troops against gas attacks. Gas was not used in World War II (1939-1945), but armies had masks in case gas warfare began. During the Persian Gulf War of 1991 and the Iraq War (2003-2011), gas masks were issued to troops and civilians in areas where it was feared Iraq would strike. But Iraq did not use such weapons. Miners, workers in chemical industries, and firefighters often use gas masks.
