Time Use Research for Exposure and Risk Assessment

1. Time Use Research for Exposure and Risk Assessment Rosemary Zaleski, ExxonMobil Biomedical Sciences, Inc., and Virpi Tenhola, KTL National Public Health Institute, Finland International Association for Time Use Reseach Brussels, Belgium, September 2003

2. Introduction Ultimate Goal: Ensuring protection of public health • Risk = function of (hazard, exposure) • Exposure data critical to estimate risk • Develop most realistic, complete estimates of exposure as possible • Time Use Information is critical to developing exposure estimates

3. Time Use Information and Exposure Assessment Exposure = Media Concentration X Intake Rate X Contact Time e.g., Inhalation Exposure (mg/day) = Pollutant in air (mg/m3) X Breathing Rate (m3/hr) X Time (hrs/day) • Occupational scenario: requires time at work in task area • Indoor residential scenario: requires time indoors at home • age-specific exposures require age-specific time indoors • multi-chamber residence models require room-specific movement patterns

4. Example of Exposure Model Input Data

5. Examples of Time Use Parameters Relevant for Exposure Assessment • Hours indoors/outdoors • Time in specific environments (home, work, school, driving) • Time in specific microenvironments (kitchen, bedroom, garage) • Time in specific tasks (gardening, recreation, bathing) • Time using or in presence of certain products (paints, adhesives, cigarettes) • Residence time, employment tenure

6. Ideal Level of Information for Time Use Parameters for Exposure Assessment • Distributions • by age • by gender • by time of year • by region or population • by activity level • by other significant factors • significant factors may differ across time parameters • ex. Day of week, employment status, education status • Sequentially (preserve potential correlations)

7. Why Does Time Use Information Matter? • A few of the many applications of time use information in exposure and risk assessment include: • Occupational exposure and safety assessment • Consumer product safety assessment • Children’s exposure assessment • Ambient air pollutant risk assessment • Environmental emissions exposure and risk assessment

8. Examples of Time Use Data in Exposure Assessment • US National Human Activity Pattern Survey: • distributional data by environments (e.g., work) and activities (e.g., bathing) • Summary data in USEPA Exposure Factors Handbook: http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=12464 • US Consolidated Human Activity Database: • includes activity level estimates for each task • http://www.epa.gov/chadnet1/

9. Examples of Time Use Data in Exposure Assessment (cont’d) • ECETOC European Exposure Factors Sourcebook, with Focus on UK Data: • OECD: years with employer for multiple countries • Gershuny 1995: estimated weekly work hours for multiple countries

10. Multinational Time Use Data: Relevance for Exposure Estimates Differences: weekly work hours & employer tenure

11. Summary So Far • Time use data for exposure assessment is nowadays mostly from the U.S. • For other countries, data are still (largely) missing • Always looking for most current, representative data • Possible ways to leverage social science and exposure science studies: • EPA/ ACC RfA announcement: http://es.epa.gov/ncer/rfa/current/2003_enviro_stat.htm • ExpoFacts: http://www.ktl.fi/expofacts/

12. ExpoFacts

13. ExpoFacts • The database will be free to use • The database will be available on the Internet • Users can search and combine data tables to best suit their needs • The database will be published in 2004 Do you have data for ExpoFacts? Do you want to use the ExpoFacts?

14. Conclusions Ultimate Goal: Ensuring protection of public health • Risk = fn (hazard, exposure) • Exposure data critical to estimate risk • Develop most realistic, complete estimates of exposure as possible • Time Use Information • Critical to developing exposure estimates • Utilize all sources of relevant data • Interdisciplinary studies - a good use of time!