The following is a short list of airborne pollutants and the American Industrial Hygiene Association, 1993, approved safe levels. You will notice that some of these items are very harmful in extremely small quantities. Asbestos 0.2 fiber/cc confirmed carcinogen Benzene 0.3 mg/m3 confirmed carcinogen Bromine 0.66 mg/m3 Cadmium 0.002 mg/m3 suspected carcinogen Carbon dioxide 9,000 mg/m3 Carbon disulfide 31 mg/m3 Carbon monoxide 29 mg/m3 Carbon tetrachloride 31 mg/m3 animal carcinogen Chlorine 1.5 mg/m3 Chloroform 49 mg/m3 suspected carcinogen Cresol 22 mg/m3 Ethanol 1,880 mg/m3 Fluorine 1.6 mg/m3 Formaldehyde 0.37 mg/m3 animal carcinogen Hydrogen cyanide 11 mg/m3 Iodine 1 mg/m3 Iron oxide (fume) 5 mg/m3 Isopropyl alcohol 980 mg/m3 Lead (fume) 0.2 mg/m3 Manganese 0.2 mg/m3 Mercury 0.01 mg/m3 Methanol 260 mg/m3 Nitric acid 30 mg/m3 Nitrogen dioxide 5.6 mg/m3 Propane asphyxiant Selenium 0.2 mg/m3 Sulfur dioxide 5.2 mg/m3 Sulfuric acid 1 mg/m3 Tellurium 0.1 mg/m3 Tetraethyl lead 0.1 mg/m3 Toluene 188 mg/m3 Turpentine 560 mg/m3 Vinyl chloride 13 mg/m3 confirmed carcinogen Zinc oxide (fume) 5 mg/m3