Air contaminants Essay Example | Topics and Well Written Essays - 250 words

Air contaminants - Essay Example Nitrogen Dioxide and Lead. Safe level of exposure can be determined. Toxic Air Contaminants: No safe level of exposure. Have over 250 compounds. Hazardous Air Pollutants: generally produced as by-products of industries. Greenhouse gases: Carbon dioxide, Methane, Nitrous oxide, fluorocarbons, Ozone. They promote climate change. Indoor air Pollutants: Mold, Volatile Organic Compounds, Radon, Ozone, Asbestos, Environmental tobacco smoke. Various methods can be adopted to sample the air pollutants occurrence and exposure in an environment. For Particulates: Cyclone is used for respirable dust sampling and works on the general principle of centrifugal and gravitational forces to separate aerosols into various size fractions. It is usually a 10mm cyclone and filter holder assembly attached to a low-flow pump and worn by the worker to obtain personal samples. Further there are many optical particulate direct reading instruments operating on the principle of the interaction between the parti cles and visible light such as Transmissometers and nephelometers. Smear technique is also used for identifying sites of contamination. Smear is done using a sterile swab that is rotated on the surface that is to be sampled. For Vapors and Gases: Electronic direct reading instruments are used based on the principles of amalgamation, chem.-luminescence, combustion, electrochemistry, infrared spectro-photometry and photo-ionization.