KEEPING INDOOR AIR QUALITY HEALTHY
Indoor air quality (IAQ) is a term referring to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants.
IAQ can be affected by microbial contaminants (mold, bacteria), gases (including carbon monoxide, radon and volatile organic compounds), particulates, or any mass or energy stressor that can induce adverse health conditions. Indoor air is becoming an increasingly more concerning health hazard than outdoor air. Using ventilation to dilute contaminants, filtration and source control are the primary methods for improving indoor air quality in most buildings.
Radon is an invisible, radioactive atomic gas that results from the radioactive decay of radium, which may be found in rock formations beneath buildings or in certain building materials themselves. Radon is probably the most pervasive serious hazard for indoor air in the United States. There are relatively simple tests for radon gas, but these tests are not commonly done, even in areas of known systematic hazards. Radon is a heavy gas and thus will tend to accumulate at the floor level. Building materials can actually be a significant source of radon, but little testing is done for stone, rock or tile products brought into building sites; radon accumulation is greatest for well-insulated homes.
The U.S. government (www.osha.gov) and some states have set standards for acceptable levels of asbestos fibers in indoor air. Many common building materials used before 1975 contain asbestos, such as some floor tiles, ceiling tiles, pipe wrap, mastics and other insulation materials. Normally, significant releases of asbestos fiber do not occur unless the building materials are disturbed, such as by cutting, sanding, drilling or building remodeling. There are particularly stringent regulations applicable to schools. Inhalation of asbestos fibers over long exposure times is associated with increased incidence of lung cancer. Asbestos is found in older homes and buildings, but it is most dangerous in schools and industrial settings. It was once widely used in shingles, fireproofing, heating systems and floor and ceiling tiles in older buildings. When asbestos-containing material is damaged or disintegrates, microscopic fibers are dispersed into the air. The risk of lung cancer from inhaling asbestos fibers is also greater to smokers. The symptoms of the disease do not usually appear until about 20 to 30 years after the first exposure to asbestos. Removal of asbestos-containing materials is not always optimal because the fibers can be spread into the air during the removal process.
Houseplants together with the medium in which they are grown can reduce components of indoor air pollution, particularly volatile organic compounds (VOC) such as benzene, toluene and xylene. Plants can also remove CO2, which is correlated with lower work performance from indoor areas. The effect has been investigated by NASA for use in spacecrafts. Plants also appear to reduce airborne microbes, molds and increase humidity.
One technique to reduce energy consumption while maintaining adequate air quality is demand controlled ventilation. Instead of setting throughout at a fixed air replacement rate, carbon dioxide sensors are used to control the rate dynamically, based on the emissions of actual building occupants.
One way of quantitatively ensuring the health of indoor air is by the frequency of effective turnover of interior air through replacement with outside air. (Source: WiKi)
Shubhang K. Patel, president of SAVITARA – General Contractors in Florida, can be reached at 1-800-245-9944 or e-mail at firstname.lastname@example.org. Orlando (407.427.2098). Tampa Bay (727.437.2098). Lakeland (863.438.1098). Lake County (352.578.1144).