Hong Kong has one of the highest bus densities in the world. LPG isn't being considered for buses, though. Officials reckon the bigger vehicles face higher risks of explosion from ruptured fuel tanks than cars. And it may be difficult to find room for the huge storage spaces needed for the great quantities of gas that will be necessary. All new buses are already required to meet the stringent emission standards set by the European Union.
Older vehicles are to install catalytic devices.
Smokestack industries in southern China are another cause of Hong Kong's worsening pall. Neighboring Guangdong province produces about 690,000 tons of sulfur dioxide each year compared to Hong Kong's 80,000 tons. Most of the SAR's factories relocated to the mainland in the early 1990s to take advantage of lower wages and to flee a ban, introduced in 1990, on sulfur-heavy fuel for industrial use. We're all under the same umbrella. Zhao says acid rain over the Pearl River delta is killing plant life and corroding buildings - in southern China and Hong Kong.