Imputation method for lifetime exposure assessment in air pollution epidemiologic studies (28 page pdf, Jan Beyea, Steven D Stellman, Susan Teitelbaum, Irina Mordukhovich, Marilie D Gammon, Environmental Health, Aug. 7, 2013)
Today we review several techniques aimed at filling gaps in the environmental record, especially those which are important because of the health impacts that may occur early (or late) in life or by proximity to higher pollution exposure. Examples include use of meteorological diffusion modeling applied to road segments and intersections and the use of surrogate doses which otherwise could be hidden or masked when applying the existing monitoring record with data gaps.
“we wanted to add individualized inhalation exposures of PAH from traffic emissions to a previously collected set of individualized PAH exposures from diet and active/passive smoking.”
“The contribution from each road segment to the air concentration at a downwind receptor residence was computed within 100 meters of a road using a highway line-source model applied to each of the 500,000, straight-line road segments in the traffic network…A key result was higher than average emissions coming from traffic intersections, which were modeled separately”
“Our finding of a consistent, strongly right-skewed distribution of traffic doses, associated with heavily trafficked intersections, means that non-standard distributions of exposure must be anticipated in studying traffic emissions.”
“The past decade has seen an increasing understanding of the importance of the impact on chronic disease risk of exposures at all stages of life, especially exposures occurring during the early years of life when many organs are still undergoing rapid and formative growth”