Humans cannot survive without air, and a few minutes without breathing air can lead to death. We can choose pollution-free water and food, but not the air we breathe. It is important to realize that the quality of indoor air is closely related to our health, as we all spend 70 to 90 percent of our day indoors and are exposed to significantly more indoor air pollutants than outdoors.

In order to improve the quality of indoor air and protect the health of residents, the Indoor Air Quality Standard (GB/T 18883-2022), which was revised by the National Bureau of Disease Prevention (NBDP) led by China, was officially released on July 11, 2022, and came into effect on February 1, 2023. The new standard further refines the types of indoor air pollutants, stipulates the physical, chemical, biological, and radiological indicators and requirements for indoor air quality, and partially regulates the exposure to indoor air pollutants. The new standard further refines the types of indoor air pollutants, stipulates physical, chemical, biological and radiological indoor air quality indicators and requirements, and puts forward more stringent requirements on the concentration of some pollutants. Most of the public buildings (e.g. office buildings) and apartments we are currently living in have increased airtightness, which, together with a wide range of modern decorative materials, makes it impossible for indoor air pollutants to be discharged from the outdoor area in a timely manner, and long periods of time in the indoor retention and accumulation of pollutants, resulting in poor or even deteriorating indoor air quality.

Therefore it is especially important to pay attention to indoor air quality and not to ignore the impact of indoor air quality on health.

Mention of indoor pollutants have to mention a term "sick building syndrome", also known as bad building syndrome, which is defined by the World Health Organization in 1979, is an office symptom that occurs in the building of an acute effect on human health. Typical symptoms include fatigue, dizziness, headache, breathlessness, shortness of breath, chest tightness, dry throat, dry eyes, nasal congestion, runny nose, watery eyes, cold symptoms, ringing in the ears, etc. The definitive cause of SBC is unknown, but pollutants from indoor/outdoor sources, including biochemical pollutants, and poor ventilation are thought to contribute to SBC. These factors may act alone or in combination with other factors (such as temperature, humidity, or lack of light), and symptoms may resolve or disappear once the patient leaves the polluted building and environment.

So what are the indoor air pollutants that create health hazards? And how can we improve indoor air quality?

I. Sources and hazards of indoor pollutants
Indoor air pollutants come from a wide range of sources, mainly formaldehyde, ammonia, benzene, radon, fine particulate matter, dust mites, mold, etc., as well as man-made second-hand smoke, carcinogens in the fumes, are a threat to human health "invisible killer".

1
Decoration materials, furniture and other harmful gases released

(1) formaldehyde, ammonia, mainly from composite flooring, furniture panels in the adhesive slow continuous release.

Formaldehyde can cause acute poisoning, pregnancy syndrome, will reduce human immunity and lead to skin damage, and even induce cancer. Indoor ammonia will not only stimulate and corrode the human upper respiratory tract and weaken immunity, but also cause cardiac arrest and respiratory arrest through the reflex action of trigeminal nerve endings.

(2) Indoor total volatile organic compounds are mainly benzene, toluene and xylene, generally from latex paint, paint, wallpaper and other materials, as well as a variety of household chemicals, benzene can damage the human body's respiratory, nervous and blood systems, and even increase the possibility of cancer.

I. Sources and hazards of indoor pollutants
Indoor air pollutants come from a wide range of sources, mainly formaldehyde, ammonia, benzene, radon, fine particulate matter, dust mites, mold, etc., as well as man-made second-hand smoke, carcinogens in the fumes, are a threat to human health "invisible killer".
1
Decoration materials, furniture and other harmful gases released

(1) formaldehyde, ammonia, mainly from composite flooring, furniture panels in the adhesive slow continuous release.
Formaldehyde can cause acute poisoning, pregnancy syndrome, will reduce human immunity and lead to skin damage, and even induce cancer. Indoor ammonia will not only stimulate and corrode the human upper respiratory tract and weaken immunity, but also cause cardiac arrest and respiratory arrest through the reflex action of trigeminal nerve endings.

(2) Indoor total volatile organic compounds (VOCs) are mainly benzene, toluene and xylene, which generally come from materials such as latex paints, lacquers, wallpapers, and a wide variety of household chemicals. Benzene compounds can damage human respiratory, nervous, and blood systems, and even increase the likelihood of cancer.

(3) The main sources of indoor radon are wall tiles, cement concrete and marble floor tiles, etc. Radon is one of the 19 major carcinogens announced by the World Health Organization (WHO), and it is the 2nd major culprit of human lung cancer after cigarettes.

2
Second-hand smoke 
Cigarette smoke has been found to contain about 4,500 chemicals, including cyclic aromatic hydrocarbons, N⁃nitrosamines, heavy metals (nickel, cadmium, chromium and arsenic), alkaloids (nicotine and its main metabolite, cotinine) and aromatic amines, etc., which can increase the risk of lung and cardiovascular diseases, as well as the incidence of tumors in the oral cavity, esophagus and bladder and other parts of the body.

In addition, e-cigarettes are also harmful, in the second-hand aerosol produced by e-cigarettes, containing polycyclic aromatic hydrocarbons, formaldehyde, specific nitrosamines and a large number of toxic organic compounds, these substances on the human body can be carcinogenic, induced by malignant tumors; e-cigarettes produced by the second-hand aerosol may contain heavy metals, such as nickel and chromium, the content of which is higher than that of ordinary cigarettes, and long-term inhalation will lead to heavy metal poisoning; second-hand Aerosols contain nicotine, which will have an adverse effect on the development of the fetus during pregnancy.

3
Kitchen fumes 

Cooking fumes contain more than 300 kinds of harmful substances, especially benzo(a)pyrene and butadiene, which are strong carcinogens. Frequent exposure to kitchen smoke and second-hand smoke during pregnancy can increase the likelihood of children developing attention deficit hyperactivity disorder.

4
Use of fossil fuels 

The burning of fossil fuels such as natural gas and coal gas can produce sulfur dioxide, carbon monoxide, nitrogen oxides and other toxic and harmful gases. In addition to damaging the human respiratory tract and the cardiovascular system, high concentrations of carbon monoxide indoors can lead to acute poisoning, which can be fatal in severe cases.

5
Dust mites, mold and other allergens 

Dust mites are mainly found in carpets, bedding and other parts of the dark and damp places are prone to mold. Mold is a class 1 carcinogen and can directly infect people with low resistance, leading to mycopneumonia. Both dust mites and molds can cause allergic reactions, leading to bronchial asthma and atopic dermatitis.

6
Atmospheric Particulate Matter 

Mainly including Total Suspended Particulate Matter (TSP), Respirable Particulate Matter (PM10), Fine Particulate Matter (PM2.5) and Ultrafine Particulate Matter (PM0.1), which enter indoors from the atmospheric environment, can affect the health of human respiratory and cardiovascular systems, as well as lower the human immunity and cause allergic and other metamorphic reactions.

II. Measures to improve indoor air quality
1
Reasonable decoration, choose environmentally friendly building materials and furniture

Choosing building materials and furniture that meet national standards is the key to improving indoor air quality. Try to choose low volatile organic compounds (VOC) materials and furniture, such as water-based paints, aldehyde-free panels. After the completion of the house decoration, it should be left to ventilate for a period of time before moving in.

2
Open windows regularly 

In the case of good outdoor air quality, opening windows is the most effective and economical way to improve indoor air quality and keep indoor air fresh and clean. Open the windows at least twice a day for at least 15-30 minutes each time. When the weather is sunny, open the windows as much as possible to let fresh air into the room.

3
Avoid Smoking Indoors 

Smoking is one of the main sources of indoor air pollution. Avoiding smoking indoors can effectively improve indoor air quality. In addition, smoking poses a threat to your family's health, so it's best to quit or refrain from smoking in your home.

4
Proper Use of Hoods, Fossil Fuels 

Hoods should be turned on early and turned off late, so that all fumes and harmful products of fuel combustion from cooking can be discharged as much as possible. Regular cleaning of hood filters, leaving a gap in the window when the hood is on, are all conducive to improving the efficiency of the hood; purchase a balanced or forced-vent gas water heater, install it correctly, and keep the room ventilated when in use; if you go to a copper stove hot pot, self-service barbecue and other direct use of fuels in the dining place, you should pay special attention to the ventilation of the place safety, to avoid carbon monoxide poisoning.

5
Replace, clean and empty garbage regularly

Regularly replace bedding, clean curtains and carpets and other items that are easy to attach allergens, keep the living environment clean and hygienic, especially in the bathroom, kitchen, bathroom and other places that are prone to mold, do a good job of classifying garbage and cleaning up in a timely manner, which can effectively remove dander, dust mites, mold and other allergens.

6
Plant green plants 

Green plants can absorb harmful substances in the air while releasing oxygen, which helps to improve indoor air quality. Planting some indoor plants such as hanging orchids and tiger's tail orchids, which have the ability to purify the air, can add a freshness to your home environment.

7
Control indoor humidity and temperature 

The right humidity and temperature can reduce the growth of bacteria and mold. Using dehumidifiers and air conditioners to control indoor humidity and temperature can improve indoor air quality by preventing humidity and mold. However, be careful to clean and sanitize dehumidifier and air conditioner filters regularly.