Now let's look at the disadvantages: 1  You don't know where the makeup air is coming from. 2  Contaminants from an attached garage or moldy crawl space can be pulled into the house. 3  Ventilation air probably won't be mixed or distributed well. 4  The only filtration that happens is through the building enclosure.
The Qing Dynasty (1644â1912) was the last Chinese dynasty, and the longest dynasty ruled by foreigners (Manchus from Manchuria, northeast of the Great Wall).
By the middle of the 18th century, the feudal economy of the Qing Dynasty reached a zenith, spanning the reign of Emperor Kangxi, Emperor Yongzheng and Emperor Qianlong. So that period was usually called 'the golden age of three emperors'.