Air pollution is known to cause severe health effects for living beings. This study uses emission factor (EF)-based investigation of pollution from mobile marine vessel stacks and on-road diesel vehicle tailpipes to supplement government policies aimed at improving the urban air quality in Hong Kong. Studies show that marine transportation constitutes majority of the local SO₂ levels in Hong Kong, whereas on-road diesel vehicle fleet is the key contributor to the street-level NO_x and PM emissions.

Aligning with IMO’s regulation to reduce SO₂ emissions, the Hong Kong government enforced the use of fuels with sulfur content below 0.5% (a significant drop from the existing 3.5% cap) for ocean going vessels (OGVs) traversing in Hong Kong waters. This study aims to provide an effici...[ Read more ]

Air pollution is known to cause severe health effects for living beings. This study uses emission factor (EF)-based investigation of pollution from mobile marine vessel stacks and on-road diesel vehicle tailpipes to supplement government policies aimed at improving the urban air quality in Hong Kong. Studies show that marine transportation constitutes majority of the local SO₂ levels in Hong Kong, whereas on-road diesel vehicle fleet is the key contributor to the street-level NO_x and PM emissions.

Aligning with IMO’s regulation to reduce SO₂ emissions, the Hong Kong government enforced the use of fuels with sulfur content below 0.5% (a significant drop from the existing 3.5% cap) for ocean going vessels (OGVs) traversing in Hong Kong waters. This study aims to provide an efficient screening tool to identify non-compliant OGVs by developing and evaluating a UAV-borne lightweight (< 750 g) microsensor system (MSS), which is capable of measuring ship plume pollutants in real-time. Laboratory and field experiments were conducted to evaluate the effects of cross-sensitivity, meteorological conditions, and plume dilutions on fuel sulfur content (FSC) estimation by the MSS. The UAV-borne MSS emerges as a robust tool for ship emissions sniffing and FSC determination.



On the other hand, two important measures were put in place by the government to alleviate emissions from the on-road diesel vehicle fleet, (i) a scheduled retirement of pre-Euro IV diesel commercial vehicles from the on-road fleet by the mid of 2020, and (ii) a new retrofit program to integrate selective catalytic reduction retrofit to Euro II and III Franchised Buses (FB) by 2017. A study of 323 vehicles was conducted by sampling medium goods vehicles (MGV), heavy goods vehicles (HGV), and FB during September 2019 – July 2020. Pollutants considered for the study included black carbon (BC), NOx, and PM. The results for the sampled vehicles showed < 3% Euro III category vehicles in the fleet, which indicates successful phasing out of the pre-Euro IV vehicles from the diesel fleet in Hong Kong. A significant drop in EF was also observed for all the pollutants and in each vehicle category. Furthermore, the Lorentz curve analysis showed that the contribution of high-emitters in emission was dominant for particle-phase pollutants. In contrast, high emitters did not dominate in the on-road NO_x emissions in both HGV and FB categories. The Lorentz curve comparison between the current and the past study (6 years ago) showed that the high emitters contribution for BC and NO_x has dropped in the current diesel fleet of Hong Kong.