Extreme value theory analysis of high emitter trends across four US cities from 1995 to 2021.

Extreme value theory provides a direct means to characterize the distribution of high emitters within a vehicle fleet and calculate statistical confidence intervals for comparisons. Defining a "high emitter" as the maximum emitter in a random sample of N vehicles implies in the limit of large N that high emitters follow an extreme value distribution, comprised of three distinct domains. The analysis of over twenty years of roadside remote sensing emissions measurements in Chicago, Denver, Los Angeles and Tulsa reveals clear differences between gasoline vehicle high emitter distributions across pollutants (hydrocarbons (HC), carbon monoxide (CO) and nitric oxide (NO)), but very similar behavior across the four cities.

Engine, aftertreatment, fuel quality and non-tailpipe achievements to lower gasoline vehicle PM emissions: Literature review and future prospects.

Spark ignition gasoline vehicles comprise most light duty vehicles worldwide. These vehicles were not historically associated with PM emissions. This changed about 15 years ago when emissions regulations forced diesel engines to employ exhaust particulate filters and fuel economy requirements ushered in gasoline direct injection (GDI) technology.

Primary gas- and particle-phase emissions and secondary organic aerosol production from gasoline and diesel off-road engines.

Dilution and smog chamber experiments were performed to characterize the primary emissions and secondary organic aerosol (SOA) formation from gasoline and diesel small off-road engines (SOREs). These engines are high emitters of primary gas- and particle-phase pollutants relative to their fuel consumption. Two- and 4-stroke gasoline SOREs emit much more (up to 3 orders of magnitude more) nonmethane organic gases (NMOGs), primary PM and organic carbon than newer on-road gasoline vehicles (per kg of fuel burned).

Influence of mileage accumulation on the particle mass and number emissions of two gasoline direct injection vehicles.

Gasoline direct injection (GDI) is a new engine technology intended to improve fuel economy and greenhouse gas emissions as required by recently enacted legislative and environmental regulations. The development of this technology must also ensure that these vehicles meet new LEV III and Tier 3 emissions standards as they phase in between 2017 and 2021. The aim of the present paper is to examine, at least for a small set, how the PM emissions from GDI vehicles change over their lifetime.

Directions for combustion engine aerosol measurement in the 21st century.

The Coordinating Research Council convened two Real-Time PM Measurement Workshops in December 2008 and March 2009 to take an intensive look at the current status and future directions of combustion aerosol measurement. The purpose was to examine the implications of parallel rapid developments over the past decade in ambient aerosol science, engine aftertreatment technology, and aerosol measurement methodology, which provide benefits and challenges to the stakeholders in air quality management. The workshops were organized into sessions targeting key issues in ambient and source combustion particulate matter (PM).