In recent years, environmental pollution incidents increase with the development of cities and industries. Frequent physical illness follows, caused by air pollutants like formaldehyde, haze and PM2.5. Therefore, people pay much more attention to develop ecological environment and indoor environment

On ISH Beijing (China International Trade Fair for Sanitation, Heating, Ventilation & Air- conditioning ) from 31st May to 1st June, sharp increase of ventilation product demand shows clearly the urgency of improving living environment. On the fair, plenty of products are exhibited. The core component of these products is fan. For example, household hood fan is usually dual inlet blowers; vacuum cleaner has built-in centrifugal fan. The built-in fan of each product differs according to function. Customers make their purchase based on requirements and professional advices from exhibitors.