Relationship of Indoor, Outdoor and Personal Air (RIOPA) study: Study design, methods and quality assurance/control results

Clifford P. Weisel, Junfeng Zhang, Barbara J. Turpin, Maria T. Morandi, Steven Colome, Thomas H. Stock, Dalia M. Spektor, Leo Korn, Arthur Winer, Shahnaz Alimokhtari, Jaymin Kwon, Krishnan Mohan, Robert Harrington, Robert Giovanetti, William Cui, Masoud Afshar, Silvia Maberti, Derek Shendell

Research output: Contribution to journalArticlepeer-review

127 Scopus citations


The Relationship of Indoor, Outdoor and Personal Air (RIOPA) Study was undertaken to evaluate the contribution of outdoor sources of air toxics, as defined in the 1990 Clean Air Act Amendments, to indoor concentrations and personal exposures. The concentrations of 18 volatile organic compounds (VOCs), 17 carbonyl compounds, and fine particulate matter mass (PM2.5) were measured using 48-h outdoor, indoor and personal air samples collected simultaneously. PM2.5 mass, as well as several component species (elemental carbon, organic carbon, polyaromatic hydrocarbons and elemental analysis) were also measured; only PM 2.5 mass is reported here. Questionnaires were administered to characterize homes, neighborhoods and personal activities that might affect exposures. The air exchange rate was also measured in each home. Homes in close proximity (<0.5 km) to sources of air toxics were preferentially (2:1) selected for sampling. Approximately 100 non-smoking households in each of Elizabeth, NJ, Houston, TX, and Los Angeles. CA were sampled (100, 105, and 105 respectively) with second visits performed at 84, 93, and 81 homes in each city, respectively. VOC samples were collected at all homes, carbonyls at 90% and PM2.5 at 60% of the homes. Personal samples were collected from nonsmoking adults and a portion of children living in the target homes. This manuscript provides the RIOPA study design and quality control and assurance data. The results from the RIOPA study can potentially provide information on the influence of ambient sources on indoor air concentrations and exposure for many air toxics and will furnish an opportunity to evaluate exposure models for these compounds.

Original languageEnglish (US)
Pages (from-to)123-137
Number of pages15
JournalJournal of exposure analysis and environmental epidemiology
Issue number2
StatePublished - Mar 2005

All Science Journal Classification (ASJC) codes

  • Environmental Chemistry
  • Toxicology
  • Environmental Science(all)
  • Pollution
  • Public Health, Environmental and Occupational Health
  • Health, Toxicology and Mutagenesis


  • Carbonyls
  • Exposure
  • PM2.5
  • Proximity to sources
  • VOC


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