Effects of Light-Duty Vehicle Emissions on Ozone and PM with Past, Present, and Future Controls: Tier - versus Other Scenarios.

摘要

MOVES and CAMx were applied to model nationwide g-LDV Tier 0 scenarios in February and July in 2008 and 2022. The Tier 0 standards, which were first implemented in 1981, were assumed to be the only standards in place in these scenarios. The results from the current work and a prior study (CRC A-76-1) were examined together to examine ozone and PM(sub 2.5) differences between the Tier 0 and Tier 2 standards implementation in 2008 and to evaluate these differences in five g-LDV emission scenarios in 2022 from least to most stringent - Tier 0, Tier 1, Tier 2, LEV-III and LDVZ (the zero-out LDV scenario). The Tier 1 scenario assumed that the standards first applied to 1994 vehicles were still in place. Tier 2 applied the current g-LDV standards. LEV-III assumed that the stricter California standards currently in place would apply to the nationwide fleet of g-LDVs; the effects of gasoline sulfur reductions were not modeled. The LDVZ scenario assumed that there were no g-LDV emissions nationwide. The four urban sites evaluated were Atlanta, Detroit, Philadelphia, and St. Louis. The 2008 Tier 0 scenario g-LDVs accounted for only 3.5% of the total anthropogenic PM(sub 2.5) emissions in the winter and 1.9% in the summer. The phasing in of progressively more stringent NOx, VOC and primary PM(sub 2.5) emissions standards up to and including the Tier 2 controls contributed to monthly average PM(sub 2.5) concentrations that were up to 1.9 mu g/m(sup 3) lower in February and up to 2 micro g/m(sup 3) lower in July in the Tier 2 scenario compared to concentrations of approximately 40 micro g/m(sup 3) modeled in the Tier 0 case.