A range hood for preventing air pollution is disclosed and includes a main body, a gas guider, a filtration and purification component and at least one gas detection module. The main body is configured to form a diversion path. The gas guider is disposed in the diversion path for guiding an air convection. The filtration and purification component is disposed in the diversion path for filtering and purifying an air pollution source contained in the air convection guided by the gas guider. The at least one gas detection module is disposed in the diversion path for detecting the air pollution source and transmitting a gas detection datum.