An Ambient Measurement Technique for Vehicle Emission Quantification and Concentration Source Apportionment

TY - JOUR

T1 - An Ambient Measurement Technique for Vehicle Emission Quantification and Concentration Source Apportionment

AU - Farren, Naomi J.

AU - Wilson, Samuel

AU - Bernard, Yoann

AU - Shaw, Marvin D.

AU - Lee, Kaylin

AU - Crowe, Mallery

AU - Carslaw, David C.

N1 - Publisher Copyright: © 2024 The Authors. Published by American Chemical Society.

PY - 2024/11/12

Y1 - 2024/11/12

N2 - We develop a new technique called plume regression where fast response instruments located at the roadside are used to measure exhaust plumes of passing vehicles. The approach is used to generate highly disaggregated vehicle emissions information by vehicle type, which compares well with traditional vehicle emission remote sensing. Additionally, the technique provides valuable new information on ambient concentration source apportionment by vehicle type. The technique is flexible enough to consider a wide range of air pollutants and be deployed at roadside ambient monitoring locations. The new approach is used to quantify emissions and concentration source apportionment for ammonia (NH3) and nitrogen oxides (NOx). We find that emissions of NH3 are generally very well controlled from diesel vehicles including those with selective catalytic reduction systems that use NH3 to reduce emissions of NOx. By contrast, gasoline passenger cars are shown to be the dominant contributor to NH3 emissions, which increase with vehicle mileage. Average fuel-specific NH3 emission factors for gasoline vehicles range from 0.3 to 1.2 g kg-1, while diesel vehicle emission factors remain below 0.06 g kg-1, with the exception of Euro VI buses with the latest regulatory provisions (0.5 g kg-1).

AB - We develop a new technique called plume regression where fast response instruments located at the roadside are used to measure exhaust plumes of passing vehicles. The approach is used to generate highly disaggregated vehicle emissions information by vehicle type, which compares well with traditional vehicle emission remote sensing. Additionally, the technique provides valuable new information on ambient concentration source apportionment by vehicle type. The technique is flexible enough to consider a wide range of air pollutants and be deployed at roadside ambient monitoring locations. The new approach is used to quantify emissions and concentration source apportionment for ammonia (NH3) and nitrogen oxides (NOx). We find that emissions of NH3 are generally very well controlled from diesel vehicles including those with selective catalytic reduction systems that use NH3 to reduce emissions of NOx. By contrast, gasoline passenger cars are shown to be the dominant contributor to NH3 emissions, which increase with vehicle mileage. Average fuel-specific NH3 emission factors for gasoline vehicles range from 0.3 to 1.2 g kg-1, while diesel vehicle emission factors remain below 0.06 g kg-1, with the exception of Euro VI buses with the latest regulatory provisions (0.5 g kg-1).

KW - ammonia

KW - plume sampling

KW - regression

KW - source apportionment

KW - vehicle emissions

UR - http://www.scopus.com/inward/record.url?scp=85208359857&partnerID=8YFLogxK

U2 - 10.1021/acs.est.4c07907

DO - 10.1021/acs.est.4c07907

M3 - Article

C2 - 39491507

AN - SCOPUS:85208359857

SN - 0013-936X

VL - 58

SP - 20091

EP - 20100

JO - Environmental Science and Technology

JF - Environmental Science and Technology

IS - 45

ER -