Issue link: https://hi.iaq.net/i/630729
Common IAQ Measurements — A General Guide 117 evaluating acute irritation. Dosimeters may accurately record long-term exposure but may miss these peaks. Two commonly used methods that are generally acceptable for IAQ screening involve impingers and sorbent tubes. Other appropriate methods are also available. Using the Results Various guidelines and standards are available for formaldehyde exposure. Several organizations have adopted 0.1 ppm as guidance that provides reasonable protection against irritational effects in the normal population. Hypersensitivity reactions may occur at lower levels of exposure. Worst-case conditions are created by minimum ventilation, maximum temperatures, and high source loadings. Biological Contaminants Human health can be affected by exposure to both living and non-living biological contaminants. The term "bioaerosols" describes airborne material that is or was living, such as mold and bacteria, parts of living organisms (e.g., insect body parts), and animal feces. Testing for biological contaminants should generally be limited to: ■ cases where a walkthrough investigation or human profile study suggests micro- biological involvement ■ cases in which no other pollutant or physical condition can account for symptoms Methodology Inspection of building sanitary conditions is generally preferred over sampling, because direct sampling can produce misleading results. Any sampling should be accompanied by observations of sanitary conditions and a determination as to whether any health problems appear likely to be related to biological contami- nation. No single technique is effective for sampling the many biological contami- nants found in indoor environments. A variety of specific approaches are used to retrieve, enumerate, and identify each kind of microorganism from water, surfaces, and air. Other specific methods are used for materials such as feces or insect parts. The utility of these techniques depends upon their use by professionals who have a thorough understanding of the sample site and the target organism. Where air sampling is desired, several approaches are available. The most common type of air sampler uses a pump to pull air across a nutrient agar, which is then incubated. Any bacterial or fungal colonies that subsequently grow can be counted and identified by a qualified microbiologist. Different types of agar and incubation temperatures are used to culture different types of organisms. Only living organisms or spores in the air are counted by this method. Settling plates, which are simply opened to room air and then incubated, are sometimes used to identify which bioaerosols are present in different locations. The drawbacks to this technique are that it does not indicate the quantity of bioaerosols present and that only the A viable impactor. Used to sample for biologicals. Training is required in order to analyze the results.