Formaldehyde is a colorless gas at room temperature and has a very pungent odor. It is classified as volatile organic compound (VOC) and is used as coating, resin and/or adhesive in many building materials. The main indoor sources of CH2O are composite wood products, such as medium density fiberboard and particle board. CH2O is also used in the manufacture of some carpet backings and urea-formaldehyde foam insulation.
When present in high concentrations CH2O can cause symptoms like eye, nose and throat irritation, coughing and breathing difficulties. Asthma attacks, nausea, vomiting, headaches and nose bleeds can also occur.
CH2O diffuses through the tube at a rate dependent on Frick’s Law of diffusion. The treated filter at the bottom end of the tube maintains a near zero CH2O concentration at the base; therefore, the quantity of CH2O transferred through the diffusion path is related to the ambient concentration and the length of time exposed. Collected CH2O is quantified in the laboratory using the chromotropic acid procedures.
The sampler consists of glass-fiber filter treated with sodium bisulfide, housed in a glass vial that is capped when not in use.