Hong Kong’s car pollution sensors help it clean its air in world first
Hong Kong has improved its air quality by using roadside sensors to detect vehicles with the dirtiest fumes and forcing owners to get them fixed. Vehicles that run on petrol and diesel emit harmful chemicals like carbon monoxide, nitrogen oxides and hydrocarbons. New cars have technology for reducing these emissions, but they can become more polluting over time. Many older cars that are still on the roads are heavy emitters. Cameras capture the licence plates of the most polluting vehicles so their owners can be notified. Owners must repair their vehicles and pass an emissions test, paid for themselves, before their vehicles are allowed back on the road.