Shower and Household Water-Use Exposure (SHOWER) Model

Environmental health professionals have long known that volatile compounds in household water can be a significant source of inhalation exposures. Showers, sinks, and other water-using appliances will release volatile compounds from water into indoor air, where they can accumulate at concentrations that adversely impact health. In addition, residents may be exposed to compounds in household water through skin contact and dermal uptake. Previous work to evaluate these exposures relied on either highly simplified estimates or complex technical models that were not widely accessible to health assessors. Easy-to-use tools that correctly capture the complexity of these exposures were sorely lacking. To meet this need, the Agency for Toxic Substances and Disease Registry requested ERG’s support for developing the Shower and Household Water-Use Exposure model.

ERG led and supported every aspect of SHOWER model development for ATSDR, including background scientific research, model verification, user interface design, application coding, and program testing. The resulting ATSDR SHOWER model allows health assessors to quickly calculate average daily inhalation air concentrations and dermal doses for households with contaminated water.

ERG has designed and released three versions of the SHOWER model for ATSDR. Version 1 provided results for a default household scenario based on only an input water concentration, and version 2 allowed health assessors to calculate results for custom scenarios. Version 3 allowed health assessors to export results from the SHOWER model for cancer and noncancer exposure calculations into another ERG-designed tool, where they could be evaluated alongside drinking water ingestion doses. The current version of the SHOWER model is available for download at https://www.atsdr.cdc.gov/pha-guidance/toolbox/.