American Healthy Homes Survey
The American Healthy Homes Survey (AHHS) is a national survey of housing-related hazards in the U.S. The AHHS collects environmental concentrations of lead and other contaminants in and around a nationally-representative sample of U.S. homes. The AHHS II will be the third in a series of HUD-sponsored national residential environmental health surveys; in the previous surveys, field data collection was completed in 2000 (National Survey of Lead and Allergens in Housing [NSLAH]) and 2006 (AHHS). Lead-based paint and associated hazards are prevalent in U.S. housing. The predominant route for exposure for children is by ingestion of lead-contaminated dust through normal hand-to-mouth behaviors, therefore reducing the prevalence of lead-based paint hazards in housing will reduce children’s lead exposure overall as well as the number of children with elevated blood lead levels (EBLL) as defined by CDC. Reducing the number of homes with lead-based paint and residential lead-based paint hazards will reduce potential sources of lead that are the primary pathways for lead ingestion by children.
The survey design was a 3-stage cluster sample of the target population. The first stage consisted of 100 Primary Sampling Units (PSUs), which were Metropolitan Statistical Areas, single counties or groups of counties. The PSUs were randomly selected with probability proportional to population according to the 2000 Census. The second stage of sampling was to select segments from each PSU with probability proportional to the number of housing units. A segment typically consisted of several city blocks, although it could be much larger in ruralareas. The number of segments in a PSU was usually 5, but ranged from 4-12 depending on the size (population) of the PSU. The third and final stage of sampling was to select a number of housing units in each segment at random. Four housing units per segment were selected in earlier PSUs and five in later PSUs. Ultimately, a sample of 2,224 housing units was drawn, from which 1,131 eligible homes were recruited and completed the survey. The principal reasons 49% of sampled homes did not complete the survey were ineligibility (10%), inability to contact a resident (10%) and refusal (23%). The NSLAH design was similar to AHHS, but the PSUs, segments and housing units selected were different.
Field operations began in late June 2005 and were completed in March 2006. A two-person team consisting of a trained interviewer and a State-certified Lead-Based Paint Inspector/Risk Assessor was dispatched to each PSU. The interviewer arrived first and spent 5 days locating, visiting and attempting to recruit and schedule the 16-25 selected housing units in the PSU, each of which had been mailed an advance letter explaining the survey and announcing the interviewer’s visit. The advance letters contained a $10 bill to get the attention of the recipient and induce them to read the letter. An additional cash incentive of $130 (to be paid after completion of all sampling) was offered to households to induce them to participate in the survey. After 5 days, the Risk Assessor arrived in the PSU and began data collection with the interviewer in units already recruited. Between data collection visits, the interviewer continued to recruit additional units. The work in the PSU continued until data had been collected in all recruited units and no further units could be recruited. Total time in a PSU ranged from 2-3 weeks, depending on the number of units successfully recruited.
In each home, the interviewer conducted an inventory of rooms and then selected 4 in which sampling was to be conducted, one room at random from each of 4 room strata – kitchens, common living areas, bedrooms (children’s only if present) and, all other rooms. If there was an accessible basement used for habitation, the largest room in it was also selected. The interviewer administered a questionnaire to a household representative, entering all data into a tablet PC in which the questionnaire was programmed. The interviewer then collected vacuum dust samples for allergen and mold analysis from the floor of the home. Concurrently with the interviewer’s activities, the Risk Assessor conducted lead testing in paint using a portable X-Ray Fluorescence (XRF) instrument, collected dust wipe floor samples for pesticides11, lead and arsenic, and took soil samples in the yard for lead and arsenic. Data collection in a home took several hours, depending on the type and size of the home.
At the end of each day, lead testing data was downloaded from the XRF to the tablet PC and emailed, along with the questionnaire data, to QuanTech’s offices. When work in a PSU was completed, the Tablet PC and all paper forms were returned to QuanTech. The Tablet PCs were then downloaded to provide a second copy of the data in addition to that sent by email. The XRF instruments were returned to the manufacturer for servicing between PSUs. The manufacturer downloaded all data from the instruments to provide a third copy of the XRF data. These redundancies in data handling ensured that no significant loss of data occurred in the AHHS.
Physical samples were stored in the PSU until all data collection was completed. Pesticide wipe samples were kept frozen in portable freezers provided to the field teams. Other samples were not frozen. At the end of activities in the PSU, all samples, with the exception of the pesticide wipes, were shipped to QuanTech’s offices for inventory, data entry and transmittal to analysis laboratories. The pesticide samples were shipped frozen overnight to a laboratory designated by EPA.
Housing units were selected as a 3-stage cluster sample of residential housing. The first stage was the selection of 100 Primary Sampling Units (PSUs) drawn from PSUs based on the 2000 Census; the second stage consisted of five census block segments in each PSU; the third was the selection of four to six candidate housing units within each segment. Trained field teams administered a survey questionnaire and collected a variety of environmental samples at each participating household. Samples were analyzed for a suite of 24 compounds using standardized laboratory and quality control procedures.
For the 2005-06 survey, a sample of 1,131 homes were selected; environmental samples were collected from a subset of 500 homes.
Stout, DM et al: American Healthy Homes Survey: A National Study of Residential Pesticides Measured from Floor Wipes. Environmental Science and Technology. 43(12): pp 4,294-4,300. 2009.