Therefore, can we say that the ban is effective? In our group, we all agree that it is ineffective in lowering the API of Hong Kong because there are many exemptions in the ban and a lot of drivers can escape from the law. Furthermore, the sources of air pollutants are not only from the vehicles, but also from the operations of factories and power stations, so only establishing law to prevent the drivers from idling the motor vehicle engines is not enough to protect our living environment. We need to have other possible solutions to help meliorating the problem.
In order to reduce the air pollutants emitted by the vehicles, we suggest installing a 3-way catalytic converter, which can oxidize carbon monoxide to carbon dioxide 2CO + O2 ---> 2CO2, unburnt hydrocarbons to carbon dioxide and water CxH2x+2 + (3x+1)/2 O2 ---> xCO2 + (x+1) H2O and reduce nitrogen oxides to nitrogen and oxygen 2NOx ---﹥N2 + xO2. Nevertheless, the catalytic converter cannot be used on leaded petrol vehicles because Lead will poison the catalyst such as Platinum inside the converter.
Indeed, there are more possible solutions to solve the problem. Expanding the rail network or using public transports instead of private cars can also improve the air quality because the amount