文摘
Benefit-cost and regulatory impact analyses often useatmospheric dispersion models with coarse resolution toestimate the benefits of proposed mobile source emissioncontrol regulations. This approach may bias healthestimates or miss important intra-urban variability forprimary air pollutants. In this study, we estimate primaryfine particulate matter (PM2.5) intake fractions (iF; the fractionof a pollutant emitted from a source that is inhaled bythe population) for each of 23 398 road segments in theBoston Metro Core area to evaluate the potential for intra-urban variability in the emissions-to-exposure relationship.We estimate iFs using the CAL3QHCR line source modelcombined with residential populations within 5000 m of eachroad segment. The annual average values for the roadsegments range from 0.8 to 53 per million, with a mean of12 per million. On average, 46% of the total exposure isrealized within 200 m of the road segment, though this variesfrom 0 to 93% largely due to variable population patterns.Our findings indicate the likelihood of substantial intra-urban variability in mobile source primary PM2.5 iF thataccounting for population movement with time, localizedmeteorological conditions, and street-canyon configurationswould likely increase.