A Formaldehyde Exposure Assessment Tool for Occupants of FEMA Temporary Housing Units

Abstract

The report outlines the methodology used to develop a web-based tool to assess the formaldehyde exposure of the occupants of Federal Emergency Management Administration (FEMA) temporary housing units (THUs) after Hurricanes Katrina and Rita in 2005. Linear regression models were built using available data to retrospectively estimate the indoor temperature and relative humidity, formaldehyde emission factors and concentration, and hence the formaldehyde exposures. The interactive web-tool allows the user to define the inputs to the model to evaluate formaldehyde exposures for different scenarios.ii LIST OF TABLES EXECUTIVE SUMMARYThe objective of this study was to estimate the formaldehyde exposure experienced by occupants of the Federal Emergency Management Administration (FEMA) temporary housing units (THUs). An empirical web-based formaldehyde exposure assessment tool was developed as described in this report.The tool is based on a set of regression models to estimate the formaldehyde emission factors in THUs. The emission factors are subsequently used to estimate exposure concentrations, which are combined with activity pattern information provided by the user to estimate the formaldehyde exposure experience by THU occupants. The regression models were derived using data from the following studies: Indoor temperature and relative humidity (RH) were also measured in all the trailers during sampling. Indoor temperatures were varied (increased or decreased) in a subset of THUs s using the heating and air conditioning systems. Indoor temperatures during sampling ranged from 14º C to 33º C, and relative humidity (RH) varied between 35% to 74%. Ventilation rates were also increased in some trailers using exhaust fans and vents during some of the sampling events. Ventilation rates varied from 0.14 to 4.3 h -1 .Weather data 3 Hourly outdoor temperature and relative humidity at weather stations near the locations of interest were obtained from National Oceanic and Atmospheric Administration (NOAA).The following regression models were constructed: 1) Indoor temperature in the THUs -A linear regression model was built with indoor temperature as the dependent variable, outdoor temperature from NOAAs weather data 3 as a continuous independent variable, and air conditioning and heating usage from CDC survey 1 as categorical independent variables. 2) Indoor relative humidity in the THUs -A linear regression model was built with indoor relative humidity as the dependent variable, outdoor relative humidity from NOAAs weather data 3 as a continuous independent variable, air conditioning and heating usage from CDC survey 1 as categorical independent variables. vi 3) Formaldehyde emission factor in the travel trailer type THUs 2 -A linear regression model was derived with formaldehyde emission factor as the dependent variable, using continuous independent variables including the log of the predicted percent indoor relative humidity, the inverse of predicted indoor temperature (in K -1 ), and the inverse log of the use...

otential Danger of Structural, Building and Finish Materials of Objects Examined by Mobile Diagnostic Groups as Part of Chemical Control

“…Как показывают исследования в области эколого-химических проблем закрытых помещений, потенциальными источниками загрязнителей воздуха, которые могут повлиять на достоверность результатов химического контроля в замкнутых объемах, при определенных условиях могут быть как сам человек, предметы и материалы, оборудование, вентиляционные системы, приборы и устройства, химические вещества, присутствующие в помещениях, так и деятельность человека и происходящие в помещениях процессы [6][7][8][9][10][11][12][13][14][15][16].…”