2.1 Number of registered vehicles and TrendsIn
The trend of vehicle registration increased at an average rate of approximately 22% annually. Almost 22% of vehicle registration in Thailand were registered in the Bangkok Metropolitan Area (BMA). However, more than 60% were actually used in the area.So This implies that most of transportation problems were intensive in Bangkok and the surrounding areas.
2.2 Energy consumption
The majority of energy in Thailand is predominantly consumed in the transport. The main fuel types are gasoline, diesel oil, and jet fuel. This may cause more severe air pollution.
2.3 Current ambient air quality
Pollution Control Department(PCD) reported that the air pollutants of greatest concern in Bangkok are suspended particulate matter, especially particulate matter (PM10), and carbon monoxide (CO). They are accounted for mostly by the transport sector.