1. A home that has just been renovated or refurbished.
2. There are elderly, children, pregnant women, and newborns.
3. The residence of people with asthma, allergic rhinitis and pollen allergy.
4. Housing for pets and livestock.
5. A residence that is more closed or affected by secondhand smoke.
6, hotels, public places.
7. The residence of people who are willing to live with high quality.
8, hospitals, reduce infections, prevent the spread of disease.