Evaluating Differences between Measured Personal Exposures to Volatile Organic Compounds and Concentrations in Outdoor and Indoor Air

Ken Sexton, John L. Adgate, Steven J. Mongin, Gregory C. Pratt, Gurumurthy Ramachandran, Thomas H. Stock, Maria T. Morandi

Research output: Contribution to journalArticle

Abstract

Accurate estimation of human exposures to volatile organic compounds (VOCs) is a key element of strategies designed to protect public health from the adverse effects of hazardous air pollutants. The focus here is on examining the capability of three different exposure metrics (outdoor community concentrations, indoor residential concentrations, and a simple time-weighted model) to estimate observed personal exposures to 14 VOCs. The analysis is based on 2-day average concentrations of individual VOCs measured concurrently in outdoor (O) air in three urban neighborhoods, indoor (1) air in participants residences, and personal (P) air near the breathing zone of 71 healthy, nonsmoking adults. A median of four matched P-I-O samples was collected for each study participant in Minneapolis/St. Paul over three seasons (spring, summer, and fall) in 1999 using charcoal-based passive air samplers (3M model 3500 organic vapor monitors). Results show a clear pattern for the 14 VOCs, with P > I > O concentrations. Intra-individual variability typically spanned at least an order of magnitude, and inter-individual variability spanned 2 or more orders of magnitude for each of the 14 VOCs. Although both O and I concentrations generally underestimated personal exposures, I concentrations provided a substantially better estimate of measured P concentrations. Mean squared error (MSE) as well as correlation measures were used to assess estimator performance at the subject-specific level, and hierarchical, mixed effects models were used to estimate the bias and variance components of MSE by tertile of personal exposure. Bias and variance both tended to increase in the upper third of the P exposure distribution for O versus P and I versus P. A simple time-weighted model incorporating measured concentrations in both outdoor community air and indoor residential air provided no improvement over I concentration alone for the estimation of P exposure.

Original languageEnglish (US)
Pages (from-to)2593-2602
Number of pages10
JournalEnvironmental Science and Technology
Volume38
Issue number9
DOIs
StatePublished - May 1 2004
Externally publishedYes

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Volatile Organic Compounds
indoor air
Volatile organic compounds
volatile organic compound
Air
air
Air Pollutants
Charcoal
Public health
spring (season)
exposure
charcoal
sampler
public health
Vapors
summer

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Science(all)
  • Environmental Chemistry

Cite this

Evaluating Differences between Measured Personal Exposures to Volatile Organic Compounds and Concentrations in Outdoor and Indoor Air. / Sexton, Ken; Adgate, John L.; Mongin, Steven J.; Pratt, Gregory C.; Ramachandran, Gurumurthy; Stock, Thomas H.; Morandi, Maria T.

In: Environmental Science and Technology, Vol. 38, No. 9, 01.05.2004, p. 2593-2602.

Research output: Contribution to journalArticle

Sexton, Ken ; Adgate, John L. ; Mongin, Steven J. ; Pratt, Gregory C. ; Ramachandran, Gurumurthy ; Stock, Thomas H. ; Morandi, Maria T. / Evaluating Differences between Measured Personal Exposures to Volatile Organic Compounds and Concentrations in Outdoor and Indoor Air. In: Environmental Science and Technology. 2004 ; Vol. 38, No. 9. pp. 2593-2602.
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