The current ventilation system can be divided into natural ventilation mechanical ventilation, the following details of the two types of ventilation.　

1, natural ventilation - this type of ventilation is the use of external air pressure circulation of the proceeding. Natural ventilation is as effective as mechanical ventilation, natural ventilation needs to rely on external natural environmental conditions, so natural ventilation is as effective as expected.

2、Mechanical ventilation - This type of ventilation utilizes fresh air equipment such as ventilation fans to circulate the air in the room. Compared with natural ventilation, this method can make a large amount of air circulation. the introduction of fresh air can be effectively controlled (size, timing, wind path), do need to rely on external natural conditions.