Publication Date

8-26-2025

Document Type

Article

Keywords

Heavy-duty diesel, Selective catalytic reduction, SCR, Temperature sensitivity, NOx

Abstract

This study investigates the effects of ambient temperature on NOx (NO + NO2) emissions from model year 2011 and later heavy-duty (HD) diesel vehicles. Emission measurements were collected in Perry, Utah, using the Fuel Efficiency Automobile Test (FEAT) remote sensing device. Data were limited to model year 2011 and later to focus on vehicles likely equipped with selective catalytic reduction (SCR) systems, which control tailpipe NOx emissions and are shown to be temperature sensitive. HD diesel vehicles measured in the winter of 2020 had consistently higher NOx emissions than those measured in the summer of 2023, most significantly for vehicles aged 0 to 3. A non-linear model fit to the data that accounts for age effects, predicts fleet-average NOx emissions to be two times higher at colder ambient temperatures (−4.4 ◦C, 24 ◦F) than warmer ambient temperatures (28.1 ◦C, 82.5 ◦F). The temperature effect from this study supports temperature effects observed in other studies measuring real-world emissions from HD diesel vehicles. One possible improvement to the accuracy of NOx emission inventories could be including a temperature effect for SCR-equipped HD diesel vehicles.

Copyright Statement / License for Reuse

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Copyright Date

2025

Rights Holder

Amber L. Gurecki Allen, Darrell B. Sonntag, Gary A. Bishop

Provenance

Received from author

File Format

application/pdf

Language

English

Extent

21 pgs

File Size

6.9 MB

Publication Statement

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/ licenses/by/4.0/).

Publication Title

Environments

Volume

12

First Page

293

Download



Share

COinS