On-Road Air Quality Associated with Traffic Composition and Street-Canyon Ventilation: Mobile Monitoring and CFD Modeling

Kwak, Kyung-Hwan; Woo, Sung Ho; Kim, Kyung Hwan; Lee, Seung-Bok; Ma, Young-Il; Sunwoo, Young; Baik, Jong‐Jin

doi:10.3390/atmos9030092

Cited by 34 publications

(16 citation statements)

References 51 publications

(55 reference statements)

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“…In addition, it is necessary to consider the effects of various environmental indices or radiation/meteorological factors on diurnal variations of urban street elements, such as floor area ratio, Bowen ratio, traffic volume, surface emissivity, clouds, winds, etc. [52][53][54]. The RST and air temperature vary in complex environments, like urban areas.…”

Section: Discussionmentioning

confidence: 99%

Diurnal Variations of Surface and Air Temperatures on the Urban Streets in Seoul, Korea: An Observational Analysis during BBMEX Campaign

et al. 2020

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In this study, we used an intensive observation dataset of a mobile observation vehicle (MOVE) to investigate the characteristics of thermal environments and diurnal variations of road surface temperature (RST) and air temperature, particularly at the urban street level, during the 2019 Building Block 3-dimensional urban Meteorological Experiment (BBMEX) campaign in Seoul. For the purpose of comparing characteristics of RST and air temperature with different surrounding thermal environments, we divided the road into four sections (S1: Open Section, S2: High-Rise Buildings, S3: Low-Rise Buildings, S4: Street Trees). This study demonstrates that the greater sky view factors (SVFs) are generally coincident with the greater RSTs, with a significance at the 5% level. The diurnal variations indicated that the time lag between observed maximum air temperature and RST has about one hour, which is attributable to an increase air temperatures above artificial pavement through heat convection with some latency. The diurnal temperature ranges (DTRs) of RST in S2 and S4 were relatively smaller than those of S1 and S3, with differences ranging from 2.9 °C to 4.5 °C. The current results will assist planners and decision makers in determining policy priorities with regard to urban street design and planning.

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Section: Discussionmentioning

confidence: 99%

Diurnal Variations of Surface and Air Temperatures on the Urban Streets in Seoul, Korea: An Observational Analysis during BBMEX Campaign

et al. 2020

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“…Onroad emissions studies have illustrated the importance of spatially-resolved urban pollution measurements [20,21]. In the last decade, the deployment of mobile urban pollution monitoring systems using different platforms (e.g., trains, bikes, other vehicles) have been demonstrated in many cities across the world, such as Brisbane, Australia [22], Ontario, Canada [23], Oakland, California [24], Beijing, China [25], Seoul, Korea [26], and Hong Kong [27]. A recent effort to outfit Google street cars across several US cities has also been successful in mapping fine-scale urban pollution gradients [24,25,28,29].…”

Section: Overview Of Recent Mobile Urban Air Quality Studiesmentioning

confidence: 99%

The TRAX Light-Rail Train Air Quality Observation Project

et al. 2019

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Observing air quality from sensors onboard light rail cars in Salt Lake County, Utah began as a pilot study in 2014 and has now evolved into a five-year, state-funded program. This metropolitan region suffers from both elevated ozone levels during summer and high PM 2.5 events during winter. Pollution episodes result predominantly from local anthropogenic emissions but are also impacted by regional transport of dust, chemical precursors to ozone, and wildfire smoke, as well as being exacerbated by the topographical features surrounding the city. Two electric light-rail train cars from the Utah Transit Authority light-rail Transit Express ("TRAX") system were outfitted with PM 2.5 and ozone sensors to measure air quality at high spatial and temporal resolutions in this region. Pollutant concentration data underwent quality control procedures to determine whether the train motion affected the readings and how the sensors compared against regulatory sensors. Quality assurance results from data obtained over the past year show that TRAX Observation Project sensors are reliable, which corroborates earlier preliminary validation work. Three case studies from summer 2019 are presented to illustrate the strength of the finely-resolved air quality observations: (1) an elevated ozone event, (2) elevated particulate pollution resulting from 4th of July fireworks, and (3) elevated particle pollution during a winter time inversion event. The mobile observations were able to capture spatial gradients, as well as pollutant hotspots, during both of these episodes. Sensors have been recently added to a third light rail train car, which travels on a north-south oriented rail line, where air quality was unable to be monitored previously. The TRAX Observation

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“…Kwak et al [23] investigated spatial and temporal variations of air pollutant concentrations in a street canyon in a central business district of Seoul, Republic of Korea, on multiple days based on complementary approaches using a mobile laboratory and a CFD model. In the emission and dispersion processes of on-road air pollutants, the high emitting vehicles (HEV) portion and the street-canyon ventilation are the determining factors of spatial and temporal variations in their on-road concentrations.…”

Section: Ventilation Modelling In Realistic Urban Districtsmentioning

confidence: 99%