The link between symptoms of office building occupants and in-office air pollution: the Indoor Air Pollution Index

The lack of an effective indoor air quality (IAQ) metric causes communication concerns among building tenants (the public),buildi ng managers (decision-makers),and IAQ investigators (engineers). The Indoor Air Pollution Index (IAPI) is developed for office buildings to bridge this communication discord. The index, simple and easily understood,employ s the range of pollutant concentrations and concentrations in the subject building to estimate a unitless single number,the IAPI,between 0 (lowest pollution level and best IAQ) and ten (highest pollution level and worst IAQ). The index provides a relative measure of indoor air pollution for office buildings and ranks office indoor air pollution relative to the index distribution of the US office building population. Furthermore,the index associates well with occupant symptoms,pe rcentage of occupants with persistent symptoms. A tree-structured method is utilized in conjunction with the arithmetic mean as the aggregation function. The hierarchical structure of the method renders not only one index value,but also several sub-index values that are critical in the study of an office air environment. The use of the IAPI for IAQ management is illustrated with an example. The decomposition of the index leads to the ranking of sampled pollutants by their relative contribution to the index and the identification of dominant pollutant(s). This information can be applied to design an effective strategy for reducing in-office air pollution

The indoor environmental index and its relationship with symptoms of office building occupants

An index for indoor environmental quality, the Indoor Environmental Index (IEI), was developed. This study aggregates the Indoor Air Pollution Index, an index found in the literature, and a new index: the Indoor Discomfort Index. The average of these two indices is the IEI, which is calculated using concentrations of eight pollutants and two comfort variables measured in 100 office buildings in the United States. The database used was developed for the U.S. Environmental Protection Agency Building Assessment Survey Evaluation study. A symptom index also is developed to denote persistent occupant symptoms. The IEI and the symptom index are used to investigate the relationship between indoor environmental quality and symptoms. Two simple linear regression models were formulated; these models explain 67 and 79% of the variation in the average symptom index, with the variation of the average IEI depending on the method of averaging used in the construction of the models. In addition, a conceptual explanation is provided for the empirical or regression models formulated. The IEI and the associated models relating indoor environmental quality with the office occupant symptom index may be used as management tools, as illustrated with an example

Exposure and risk estimates for Arizona drinking water

As part of the National Human Exposure Assessment Survey, a multistage sampling was used to estimate and compare exposures and risks associated with drinking water for two groups - the population of Arizona and that of border communities. There had been some concern that the border communities' exposures would be higher than those of other parts of the state because of their proximity to Mexico, where environmental quality may not be as high a priority as it is in the United States. The two study populations were further categorized by gender, age, ethnicity, education, income, and building structure type and year of construction. For these subgroups, the study estimated and compared risks for arsenic, 1,3-butadiene, chloroform, chromium, 1,2-dichloroethane, dichloromethane, lead, nickel, and toluene. For almost all of the sample subjects, residue concentrations were below the drinking water guideline values of both Arizona and the US Environmental Protection Agency. Of the metals studied, arsenic was the only one with a population carcinogenic risk above the acceptable level of 1.0E-6. Contrary to expressed concerns, average daily exposures and associated risks were estimated to be smaller in the border communities than in the Arizona population. For utilities, one finding deserving further study was that risks from tap water were estimated to be greater than risks from nontap water. Further research may be warranted to uncover the causes for these elevated risks