The olfactory threshold for chlorine is 0.06mg/m^3; 90mg/m^3 (28PPM), which can cause severe cough; 120~180mg/m^3 (38PPM), 30~60min can cause toxic pneumonia and pulmonary edema; at 300mg/m^3 (95PPM), it can cause fatal damage; At 3000mg/m^3, it is life-threatening; up to 30,000mg/m^3 (9478PPM), general filtering gas masks also have no protective effect.