Extreme Value Theory View of High Emitter Diesel Vehicles in the US from 1991 to 2021
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View abstract on PubMed
Summary
This summary is machine-generated.Extreme value theory (EVT) reveals that high-emission diesel vehicles disproportionately impact air quality. Their emissions of carbon monoxide, hydrocarbons, and nitric oxide have not improved with newer standards, unlike average fleet emissions.
Area Of Science
- Environmental Science
- Statistical Modeling
- Automotive Engineering
Background
- High-emission vehicles significantly contribute to adverse air quality.
- Understanding emission trends in the US diesel fleet is crucial for effective environmental policy.
- Previous studies have highlighted disparities in emission reduction strategies.
Purpose Of The Study
- To apply Extreme Value Theory (EVT) to analyze high emitter emissions in the US diesel fleet.
- To compare the response of high emitter emissions to fleet average emissions under various US Environmental Protection Agency (EPA) emissions standards.
- To investigate the disparity between fleet average and high emitter emissions.
Main Methods
- Utilized Extreme Value Theory (EVT) to analyze the tails of emission distributions for the US diesel fleet.
- Examined emissions data for Carbon Monoxide (CO), Hydrocarbons (HC), and Nitric Oxide (NOx).
- Compared emission trends of high emitters against fleet averages across different EPA Tier standards (Tier 1, 2, 3) and the 2010 NOx standard.
Main Results
- EVT confirmed that high emitters disproportionately affect air quality.
- CO and HC high emitter emissions decreased with EPA Tier 1 standards but plateaued with Tiers 2 and 3.
- Fleet average NOx emissions declined after the 2010 standard, while 99th percentile NOx emissions showed no impact.
Conclusions
- A growing disparity exists between fleet average and high emitter emissions in the US diesel fleet.
- Current emissions standards have had a differential impact on high emitters compared to the average fleet.
- Addressing high emitter emissions may be more effective for improving air quality than solely tightening new vehicle standards.
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