Due to high roadside pollution from motor vehicles and high regional emissions caused by vehicles, factories and power plants, Hong Kong has been unable to achieve its current Air Quality Objectives (AQOs). These AQOs were set in 1987 as part of Hong Kong's Air Pollution Control Ordinance. While the government has proposed a new set of Air Quality Objectives, to be implemented as early as 2014, meeting them will require the adoption of new air quality improvement measures. Biodiesel can play a role in helping Hong Kong meet its immediate air quality goals.

Currently, Hong Kong maintains standards for the biodiesel that can be used in local motor vehicles, set out in the Air Pollution Control (Motor Vehicle Fuel) Regulation. Pure motor vehicle biodiesel and blends must include fuel that meets standards comparable to the EU's EN 14214 standard. Labeling is required for selling motor vehicle diesel blends of 5 percent biodiesel (B5) or above. However, unlike in many European and Asian countries, the use of biodiesel in Hong Kong is voluntary, meaning that the potential for emissions reduction from biodiesel is still unrealized.

Hong Kong has already tested the feasibility of using biodiesel in motor vehicles. A 2003 study conducted for the Environmental Protection Department found that, for a 20 percent blend (B20), there was a 16 percent decrease in smoke opacity, a 14 percent decrease in carbon monoxide emissions, and a 14 percent decrease in hydrocarbon emissions. Nitrogen oxide emissions were little changed. These results confirmed the findings of international research, including a 2002 study by the US Environmental Protection Administration.

These numbers show that blending biodiesel in with fossil diesel can help reduce the emissions that cause pollution and contribute to respiratory, circulatory and nervous system diseases in the community.