Critical evaluation of US on-road vehicle emission inventories

摘要: US Environmental Protection Agency estimates of on-road vehicle emissions are compared with ambient measurements and a fuel-based emission inventory. Several significant weaknesses strengths identified. (1) The have varied considerably over the past 15 years not clearly converging to progressively more accurate certain results. (2) most recent estimate accurately captures rapid decrease in carbon monoxide (CO) volatile organic compounds (VOC) emissions, but overestimates magnitude CO by about factor two. (3) oxides nitrogen (NOx) for mid late 1990s reasonably accurate, NOx increased through that decade rather than decreased as indicated estimates. (4) apportions between diesel gasoline fueled vehicles did earlier reports. (5) ratio two specific VOC species has been characterized suggests inventory speciation VOCs is inaccurate factors 3–4. These tests lead derivation “inferred emissions” from fleet consistent all information used these tests. Finally, it shown international picture inaccuracies inconsistencies.