Abstract
The real-world emission factors of gaseous and particulate air pollutants emitted from in-use vehicles, can be rapidly estimated using monitoring data of their concentration profiles from inside roadway tunnels using a mobile laboratory equipped with fast monitoring instruments. The concentrations of CO2 and particle-bound polycyclic aromatic hydrocarbons (PM-PAHs) and NOx, were observed to increase linearly with traveling distance inside two successive roadway tunnels: the Hongjimun Tunnel and the Jeongneung Tunnel on the Naebu Express Way in Seoul, Korea, except for a small region of decrease. In the decreasing regions, within a few hundred meters of the entrance and before the exit, outside background air with low concentrations of air pollutants was thought to have intruded. From the slopes of the linear regression between distance and concentrations, a fleet-averaged (light-, medium-, and heavy-duty vehicles with 54%, 36%, and 10%, respectively) emission factor of CO2, PM-PAHs, and NOx at an average speed of ~60 km h−1 could be calculated as 197 ± 38 g km−1, 4.2 ± 0.8 × 10−4 g km−1, and 0.530 ± 0.230 g km−1, respectively, which are within the ranges of values reported in the literature. For each tunnel, the emission factors of CO2, PM-PAHs, and NOx estimated on days with higher-than-normal fractions of heavy-duty vehicles, were higher than those on other days. From these results, the new fast method proposed in this study is considered useful for estimating real-world emission factors of air pollutants by using a mobile laboratory as a complementary tool to traditional tunnel studies. This method can be used to rapidly make emission maps at roadway tunnels in mega-cities like Seoul, Korea, for urban air-quality management.
Highlights
IntroductionVehicles are well known as major air-pollutant sources in urban areas, especially in mega-cities such as Seoul, Korea
The fleet average CO2 emission factor derived from the two roadway tunnels in this study shows a similar level to that of medium-duty diesel vehicles, and is between those of light-duty gasoline vehicles and heavy-duty diesel vehicles
To establish a new traffic-related environmental policy and to evaluate existing ones, the real-world emission factors of gaseous and particulate air pollutants emitted from inuse vehicles need to be investigated at low cost over short time periods on many different major roads in mega-cities such as Seoul, Korea
Summary
Vehicles are well known as major air-pollutant sources in urban areas, especially in mega-cities such as Seoul, Korea. Among vehicle emissions are hazardous gases such as CO and NOx , greenhouse gases including CO2 , and carcinogens including polycyclic aromatic hydrocarbons (PAHs). In 2012, diesel exhaust particles were classified as carcinogenic (Group 1) for lung cancer based on a cohort and case study [1,2]. The emission of air pollutants from vehicles should be managed to improve air quality and public health and mitigate global warming
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
