Variability in Observation-based Onroad Emission Constraints from a Near-road Environment.

ABSTRACT: This study uses Las Vegas near-road measurements of carbon monoxide (CO) and nitrogen oxides (NO_x) to test the consistency of onroad emission constraint methodologies. We derive commonly used CO to NO_x ratios (ΔCO:ΔNO_x) from cross-road gradients and from linear regression using ordinary least squares (OLS) regression and orthogonal regression. The CO to NO_x ratios are used to infer NO_x emission adjustments for a priori emissions estimates from EPA's MOtor Vehicle Emissions Simulator (MOVES) model assuming unbiased CO. The assumption of unbiased CO emissions may not be appropriate in many circumstances but was implemented in this analysis to illustrate the range of NOx scaling factors that can be inferred based on choice of methods and

SUBMITTER: Simon H 

PROVIDER: S-EPMC7821344 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature