Publication Date

8-5-2025

Document Type

Article

Organizational Units

Chemistry and Biochemistry

Keywords

Vehicle emissions, High emitters, Extreme value theory, On-road remote sensing

Abstract

Extreme value theory (EVT) is a statistical method to characterize the tails of distributions, such as high emitter vehicle emissions. The present work addresses the United States (US) diesel fleet. EVT confirms that high emitters contribute disproportionately to adverse air quality. It further reveals that high emitter emissions have responded differently to progressively tighter emissions standards compared to fleet averages. Carbon monoxide (CO) and hydrocarbons (HC) high emitter emissions fell in concert with the fleet average after widespread implementation of the diesel oxidation catalyst to meet US Environmental Protection Agency (EPA) Tier 1 emissions standards, but remained unchanged after introduction of Tier 2 and 3 standards, even as fleet averages continued to decline. Whereas fleet average diesel nitric oxide (NO) emissions saw a steep decline following EPA’s 2010 diesel engine NOx standard, the mean 99th percentile emissions showed no impact. These results combined with our previous gasoline vehicle high emitter study demonstrate a growing disparity between fleet average and high emitter emissions. Addressing this disparity may present a more productive route to improved air quality than continued tightening of new vehicle emissions standards.

Rights Holder

M. Matti Maricq, Gary A. Bishop

Provenance

Received from author

File Format

application/pdf

Language

English

Extent

33 pgs

File Size

3.9 MB

Publication Statement

This is an accepted manuscript for

Maricq, M. M.; Bishop, G. A., Extreme Value Theory View of High Emitter Diesel Vehicles in the US from 1991 to 2021. Environ. Sci. Technol. 59 (32), 17137-17144. https://doi.org/10.1021/acs.est.5c05696

Copyright held by the American Chemical Society. User is responsible for all copyright compliance.

Publication Title

Environmental Science & Technology

Volume

59

Issue

32

First Page

17137

Last Page

17144

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