title: From measures to models: an evaluation of air pollution exposure assessment for epidemiological studies of pregnant women.
abstract: OBJECTIVE
  To evaluate exposure estimation methods such as spatially resolved land-use regression models and ambient monitoring data in the context of epidemiological studies of the impact of air pollution on pregnancy outcomes.
  
  
  METHODS
  The study measured personal 48 h exposures (NO, NO(2), PM(2.5) mass and absorbance) and mobility (time activity and GPS) for 62 pregnant women during 2005-2006 in Vancouver, Canada, one to three times during pregnancy. Measurements were compared to modelled (using land-use regression and interpolation of ambient monitors) outdoor concentrations at subjects' home and work locations.
  
  
  RESULTS
  Personal NO and absorbance (ABS) measurements were moderately correlated (NO: r = 0.54, ABS: r = 0.29) with monitor interpolations and explained primarily within-subject (temporal) variability. Land-use regression estimates including work location improved correlations for NO over those based on home postal code (for NO: r = 0.49 changed to NO: r = 0.55) and explained more between-subject variance (4-20%); limiting to a subset of samples (n = 61) when subjects spent >65% time at home also improved correlations (NO: r = 0.72). Limitations of the GPS equipment precluded assessment of including complete GPS-based mobility information.
  
  
  CONCLUSIONS
  The study found moderate agreement between short-term personal measurements and estimates of ambient air pollution at home based on interpolation of ambient monitors and land-use regression. These results support the use of land-use regression models in epidemiological studies, as the ability of such models to characterise high resolution spatial variability is "reflected" in personal exposure measurements, especially when mobility is characterised.
authors: School of Environmental Health, The University of British Columbia, Vancouver, BC, Canada. enethery@interchange.ubc.ca
authors: E
authors: E
authors: Nethery
authors: S E
authors: SE
authors: Leckie
authors: K
authors: K
authors: Teschke
authors: M
authors: M
authors: Brauer
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000706:statistics & numerical data*; D002170:Canada / Q000453:epidemiology; D004784:Environmental Monitoring / Q000379:methods; D062665:Epidemiological Monitoring; D005260:Female; D006801:Humans; D019570:Inhalation Exposure / Q000706:statistics & numerical data*; D016015:Logistic Models; D018811:Maternal Exposure / Q000706:statistics & numerical data*; D009569:Nitric Oxide / Q000032:analysis; D009585:Nitrogen Dioxide / Q000032:analysis; D010316:Particle Size; D011247:Pregnancy
chemical_list: D000393:Air Pollutants; D009569:Nitric Oxide; D009585:Nitrogen Dioxide