What are the effects of indoor environment on health? What are the advantages and disadvantages?

With the rise of building decoration fever and the improvement of indoor airtightness, the concentration of indoor air pollutants has increased. Tests show that indoor concentrations of formaldehyde, benzene series, ammonia gas, radon and other pollutants are much higher than outdoor ones, leading to more and more patients with "sick building syndrome", and indoor air pollution has become an important factor affecting human health. Inhalable particles larger than 10μm are mostly blocked in the upper respiratory tract (nasal cavity and throat), while inhalable particles smaller than 10μm can enter the lower respiratory tract through the throat, especially fine particles smaller than 2.5m can be deposited in alveoli, which is more harmful to human health. The chemical composition of particulate matter is very complicated. At the same time, fine particles enrich toxic metals, acidic oxides and organic pollutants in the air, and carry bacteria and viruses into the human body, endangering human health and safety. The harm to human health includes: toxic effect on respiratory tract, damage to lower respiratory tract and alveolar function, and influence on immune function; Absorption of harmful gases produces synergistic toxicity, and absorption of solar radiation produces mutagenicity and carcinogenicity.