It could be seen that, pollution is now a common place term because it seems that people have to face it everyday and it has also taken place in many recent years. To explain to this problem, there are some main reasons for it. The first reason is transport vehicle emissions. As you know, the number of cars and motorbikes is rapidly increasing,while local people do not have the habit to walk, especially in two major cities: Hanoi and HoChiMinh City. According to MONRE warned in a 2007 report that the pressure of socio-economic development would lead to environmental  degradation. Also, according to this, the main offender of air pollution in big cities is vehicular traffic, which contributes 85% of the amount of carbon monoxide in the air.Motorbikes increased 400% from 1996 to 2006. The total number of motor vehicles is continuously increasing every year (10% for cars and 15% for motorbikes). This growth significantly contributes to the degrading of air qualitiy in the city (VCAP and VAI-Asia, 2008). Those numbers may surge in next years because of the increase of population in Vietnam and affect negatively air environment on account of waste from transportations. In detail, with more than 600,000 cars, it consumed 4 million litters of fuel a day. Although we rely on them to fulfill our daily basic needs of transportation, overusing it may destroy environment as dangerous gases and others.Besides, exhaust from factories and industries is also contribute to air pollution, especially manufacturing industries which can be found at everywhere. It releases a large amount of harmful substances  such as carbon monoxide, hydrocarbons, organic compounds, and chemicals into the air; therefore, this makes lessen the quality of the air.In some production facilities, due to backward production technology or also due to the awareness of business owners who are only care about the immediate benefit and discharge the waste indiscriminately without treatment.. As the recent researchs, in the electricity manufacturing structure, the proportion of coal thermal power plants in Vietnam is relatively high, more than 50% with about 20 factories. 50 cement factories and 40 steel processing factories are major air pollution sources in Vietnam.Finally,except above,the construction of apartment, high-storey buildings and works in cities also cause dust pollution if vehicles going in and out of these construction sites are not properly managed. Moreover, domestic activities of households have big effects toward air pollution. As you may know, keeping homes warm is a essential thing of each family when winter comes, it means they tend to use more fossil fuels such as oil, gas, and coal. While large cities in Vietnam is rapidly unbanizing leading to an increased population.For example, in 2007, Hanoi has approximately 3.5 millions registered inhabitants with a population density of about 4 persons/km2 (Hanoi statistical office, 2008). It means the more dwellers increase, the more gases is used. Furthermore, home cooking also play an importance role in causing air pollution. The energy in cooking come from energy plants which is one of the sources of air pollutants. Alternatively, in somewhere, home cooking requires direct burning of wood or coals, which produces a large number of poison gases, and make the quality of the air more dangerous.