Chemical Characteristics and Ozone Production in the Northern Colorado Front Range

Pfister, Gabriele; Wang, Chi-Tsan; Barth, M. C.; Flocke, Frank; Vizuete, William; Walters, Stacy

doi:10.1029/2019jd030544

Cited by 21 publications

(34 citation statements)

References 68 publications

(68 reference statements)

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“…Its photolysis is a source of both OH and HO 2 radicals, which both serve to drive tropospheric O 3 formation. As a result of HCHO's carcinogenic nature and role in tropospheric ozone formation, a wealth of research has been done to better elucidate sources of formaldehyde [8][9][10][11][12]. HCHO can be directly emitted into the atmosphere from both anthropogenic and biogenic sources.…”

Section: Introductionmentioning

confidence: 99%

Sources of Formaldehyde in Bountiful, Utah

et al. 2021

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The U.S Environmental Protection Agency’s National Air Toxics Trends Stations Network has been measuring the concentration of hazardous air pollutants (HAPs) including formaldehyde (HCHO) since 2003. Bountiful, Utah (USA) has served as one of the urban monitoring sites since the network was established. Starting in 2013, the mean concentration of HCHO measured in Bountiful, Utah exceeded the non-cancer risk threshold and the 1 in 1 million cancer risk threshold. In addition, the measured concentrations were more than double those found at surrounding locations in Utah. A Positive Matrix Factorization (PMF) analysis using PMF-EPA v5 was performed using historical data (2004–2017) to better understand the sources of formaldehyde in the region. The historical data set included samples that were collected every sixth day on a 24 h basis. Beginning in February 2019 an eight-week air sampling campaign was initiated to measure formaldehyde on a two-hour averaged basis. In addition, the measurements of O3, NO, NO2, benzene, toluene, ethylbenzene, and xylenes (BTEX) were also collected. Corresponding back-trajectory wind calculations for selected time periods were calculated to aid in the understanding of the effects of BTEX emission sources and formaldehyde formation. The results indicate that the principal formaldehyde sources are associated with biomass burning and the conversion of biogenic emissions into HCHO. Back-trajectory wind analysis of low (≤3 ppbv) and high (23.8–32.5 ppbv) HCHO cases show a clear dominance of high HCHO originating in trajectories that come from the southwest and pass over the area of the oil refineries and industrial sources in the north Salt Lake City area.

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Section: Introductionmentioning

confidence: 99%

Sources of Formaldehyde in Bountiful, Utah

et al. 2021

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“…CO is the most abundant pollutant released from vehicles (373 864 t yr −1 ) across all pollutants from on-road automobile sources. Although CO is much less reactive than other vehicle VOCs (Rinke and Zetzsch, 1984;Liu and Sander, 2015), CO emissions play a critical role in generating 30 % of all hydroperoxyl radicals (HO 2 ) and cause ozone formation in urban areas (Pfister et al, 2019). Thus, CO is also another crucial precursor to ozone formation in urban areas.…”

Section: On-road Emissions Analysismentioning

confidence: 99%

The Comprehensive Automobile Research System (CARS) – a Python-based automobile emissions inventory model

et al. 2022

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Abstract. The Comprehensive Automobile Research System (CARS) is an open-source Python-based automobile emissions inventory model designed to efficiently estimate high-quality emissions from motor vehicle emission sources. It can estimate air pollutant, greenhouse gas, and air toxin criteria at any spatial resolution based on the spatiotemporal resolutions of input datasets. The CARS is designed to utilize local vehicle activity data, such as vehicle travel distance, road-link-level network geographic information system (GIS) information, and vehicle-specific average speed by road type, to generate an automobile emissions inventory for policymakers, stakeholders, and the air quality modeling community. The CARS model adopted the European Environment Agency's on-road automobile emissions calculation methodologies to estimate the hot exhaust, cold start, and evaporative emissions from on-road automobile sources. It can optionally utilize average speed distribution (ASD) of all road types to reflect more realistic vehicle speed variations. In addition, through utilizing high-resolution road GIS data, the CARS can estimate the road-link-level emissions to improve the inventory's spatial resolution. When we compared the official 2015 national mobile emissions from Korea's Clean Air Policy Support System (CAPSS) against the ones estimated by the CARS, there is a significant increase in volatile organic compounds (VOCs) (33 %) and carbon monoxide (CO) (52 %) measured, with a slight increase in fine particulate matter (PM2.5) (15 %) emissions. Nitrogen oxide (NOx) and sulfur oxide (SOx) measurements are reduced by 24 % and 17 %, respectively, in the CARS estimates. The main differences are driven by different vehicle activities and the incorporation of road-specific ASD, which plays a critical role in hot exhaust emission estimates but was not implemented in Korea's CAPSS mobile emissions inventory. While 52 % of vehicles use gasoline fuel and 35 % use diesel, gasoline vehicles only contribute 7.7 % of total NOx emissions, whereas diesel vehicles contribute 85.3 %. However, for VOC emissions, gasoline vehicles contribute 52.1 %, whereas diesel vehicles are limited to 23 %. Diesel buses comprise only 0.3 % of vehicles and have the largest contribution to NOx emissions (8.51 % of NOx total) per vehicle due to having longest daily vehicle kilometer travel (VKT). For VOC emissions, compressed natural gas (CNG) buses are the largest contributor at 19.5 % of total VOC emissions. For primary PM2.5, more than 98.5 % is from diesel vehicles. The CARS model's in-depth analysis feature can assist government policymakers and stakeholders in developing the best emission abatement strategies.

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“…CO is the most abundant pollutant released from vehicles (373,864 t yr -1 ) across all pollutants from onroad automobile sources. Although CO is much less reactive than other vehicle VOCs (Rinke and Zetzsch, 1984;Liu and Sander, 2015), the majority of CO emissions from onroad automobile sources plays a critical role in generating 30% of hydroperoxyl radicals (HO2) and causing ozone formation in urban areas (Pfister et al, 2019). Thus, CO is also another crucial precursor to ozone formation in urban areas.…”

Section: Onroad Emissions Analysismentioning

confidence: 99%

Comprehensive Automobile Research System (CARS) – a Python-based Automobile Emissions Inventory Model

Baek

Pedruzzi

Park

et al. 2021

Preprint

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Abstract. The Comprehensive Automobile Research System (CARS) is an open-source python-based automobile emissions inventory model designed to efficiently estimate high quality emissions from motor-vehicle emission sources. It can estimate the criteria air pollutants, greenhouse gases, and air toxics in various temporal resolutions at the national, state, county, and any spatial resolution based on the spatiotemporal resolutions of input datasets. The CARS is designed to utilize the local vehicle activity database, such as vehicle travel distance, road link-level network Geographic Information System (GIS) information, and vehicle-specific average speed by road type, to generate a temporally and spatially enhanced automobile emissions inventory for policymakers, stakeholders, and the air quality modeling community. The CARS model adopted the European Environment Agency's (EEA) onroad automobile emissions calculation methodologies to estimate the hot exhaust, cold start, and evaporative emissions from onroad automobile sources. It can optionally utilize road link-specific average speed distribution (ASD) inputs to reflect more realistic vehicle speed variations by road type than a road-specific single averaged speed approach. Also, utilizing high-resolution road GIS data allows the CARS to estimate the road link-level emissions to improve the inventory's spatial resolution. When we compared the official 2015 national mobile emissions from Korea's Clean Air Policy Support System (CAPSS) against the ones estimated by the CARS, there is a moderate increase of VOC (33 %), CO (52 %), and fine particulate matter (PM2.5) (15 %) emissions while NOx and SOx are reduced by 24 % and 17 % in the CARS estimates. The main differences are driven by the usage of different vehicle activities and the incorporation of road-specific ASD, which plays a critical role in hot exhaust emission estimates but wasn’t implemented in Korea’s CAPSS mobile emissions inventory. While 52% of vehicles use gasoline fuel and 35 % use diesel, gasoline vehicles only contribute 7.7 % of total NOx emissions while diesel vehicles contribute 85.3 %. But for VOC emissions, gasoline vehicles contribute 52.1 % while diesel vehicles are limited to 23 %. While diesel buses are only 0.3 % of vehicles, each vehicle has the largest contribution to NOx emissions (8.51 % of NOx total) due to its longest daily VKT. For VOC, CNG buses are the largest contributor with 19.5 % of total VOC emissions. It indicates that the CNG bus is better for the rural area while the diesel bus is better applicable for the urban area for a better ozone control strategy because the rural area is usually NOx limited for ozone formation and urban area is VOC limited region. For primary PM2.5, more than 98.5 % is from diesel vehicles. The CARS model's in-depth analysis feature can assist government policymakers and stakeholders develop the best emission abatement strategies.

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Chemical Characteristics and Ozone Production in the Northern Colorado Front Range

Cited by 21 publications

References 68 publications

Sources of Formaldehyde in Bountiful, Utah

Sources of Formaldehyde in Bountiful, Utah

The Comprehensive Automobile Research System (CARS) – a Python-based automobile emissions inventory model

Comprehensive Automobile Research System (CARS) – a Python-based Automobile Emissions Inventory Model

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