1. Engine Efficiency: Two-wheelers typically have smaller engines compared to four-wheelers. Smaller engines tend to be less efficient and release more pollutants per unit of fuel consumed.
2. Combustion Technology: Two-wheelers often use older and less advanced combustion technologies compared to modern four-wheelers. These older technologies result in higher emissions of pollutants such as hydrocarbons, carbon monoxide, and nitrogen oxides.
3. Emission Controls: Many two-wheelers, especially older models, may lack advanced emission control systems such as catalytic converters and oxygen sensors. These systems help reduce harmful emissions by converting pollutants into less harmful substances.
4. Two-Stroke Engines: Some two-wheelers use two-stroke engines, which are known to produce more pollution than four-stroke engines. Two-stroke engines do not have a dedicated exhaust stroke, leading to incomplete combustion and higher emissions.
5. Traffic Congestion: Two-wheelers are more commonly used in urban areas with congested traffic conditions. Frequent stops and starts, idling, and slow-moving traffic can contribute to increased pollution levels from two-wheelers.
However, it's worth noting that advancements in technology, emission regulations, and the introduction of electric two-wheelers are helping reduce pollution from this sector. Many modern two-wheelers now come equipped with fuel injection, catalytic converters, and other emission control measures to minimize their environmental impact.
On the other hand, trains and airplanes generally have more efficient engines, advanced emission control systems, and better fuel utilization, resulting in lower pollution levels per passenger compared to two-wheelers.
