The environmental effects of the CNG bus program on metropolitan air quality in Korea

Abstract

This study aims to analyze the effectiveness of the compressed natural gas (CNG) bus program on air quality in seven metropolitan cities in Korea. Two hundred and fifty-nine cases from monthly panel data covering June 2005 to June 2008 were analyzed. Natural and sociological characteristics in each city were included as control variables. The Chinese Air Pollution Index was also considered based on previous studies demonstrating that air quality in Korea is adversely affected by transboundary pollution from China. The relationship between five air pollutants (SO 2 , NO 2 , O 3 , CO, and PM 10 ) and the CNG bus ratio was analyzed by panel data analysis. The key findings are as follows. CO and PM 10 significantly decrease with an increase in the CNG bus ratio. On the other hand, SO 2 and NO 2 demonstrate no statistically significant relationship with CNG bus ratio, while O 3 appears to have a slightly positive relationship. In addition, the results indicate that air pollution from China contributes to the increase in PM 10 and O 3 in Korea approximately at the threshold of 100 in Chinese Air Pollution Index. Even though introducing CNG buses can reduce the level of PM 10 , it might be also increased due to the pollutants from China.

Highly active and stable nano NiO–MgO catalyst encapsulated by silica with a core–shell structure for CO2 methanation

“…Furthermore, CH 4 is one of the promising hydrogen carriers 13 considering the existing infrastructure for transport and storage of natural gas. 14 Thus, methanation of carbon dioxide is the most advantageous catalytic process in CO 2 conversion. Nevertheless, the reduction of CO 2 to CH 4 is an eight-electron process with signicant kinetic limitation, which requires an active and cheaper catalyst to achieve an acceptable rate and selectivity.…”

Analysis of External Costs of Co2 Emissions for CNG Buses in Intercity Bus Service

“…The aforementioned studies encompass the Wang et al (2011) study, which stresses that CNG buses, when compared to Euro III and Euro IV diesel buses emit considerably less NO x and PM. The fact that CNG buses emit less NO x has been confirmed by Zhang et al (2014) too, while Park and Tak (2012) reveal that CNG buses emit considerably less both PM 10 and CO.…”

Sustainable transportation strategies for decoupling road vehicle transport and carbon dioxide emissions

“…On the other hand, diesel cars generate more conventional air pollutants than gasoline cars (Mayeres and Proost, 2013). Compressed natural gas (CNG) is a popular alternative to replace conventional diesel on buses because its purification process eliminates several pollutants that are contained in other fossil fuels (Park and Tak, 2012) and also because this has the potential to reduce health risks (Cohen, 2005). In addition to the benefits mentioned above, it is also more cost effective than diesel (Rose et al, 2013).…”