1. Chemical properties of ammonia
Ammonia is a colorless and strongly pungent odorous gas that is lighter than air (specific gravity 0.5).
2. Harm of ammonia to the human body
Ammonia is an alkaline substance that has a corrosive and irritating effect on the skin tissue it comes into contact with, can absorb water in the skin tissue, denature tissue proteins, and saponify tissue fat, destroying cell membrane structure. When the concentration is too high, in addition to corrosion, it can also cause cardiac arrest and respiratory arrest through the reverse action of trigeminal nerve endings. Ammonia is usually inhaled into the alveoli in the form of gas, and after ammonia is inhaled into the lungs, it is easy to enter the bloodstream through the alveoli, bind to hemoglobin, and destroy the oxygen transport function. Ammonia has extremely high solubility, so it mainly has an irritating and corrosive effect on the upper respiratory tract of animals or the human body, weakening the body's resistance to diseases. A small part of the ammonia is neutralized by carbon dioxide, and the remaining small amount is absorbed into the bloodstream and excreted through sweat, urine or the respiratory tract. Some people may experience symptoms such as skin pigmentation or finger ulcers when exposed to ammonia for a long time; In the short term, after inhaling a large amount of ammonia, tearing, sore throat, hoarseness, cough, bloodshot sputum, chest tightness, dyspnea, may be accompanied by dizziness, headache, nausea, vomiting, fatigue and other symptoms, and in severe cases, pulmonary edema, adult respiratory distress syndrome, and respiratory irritation symptoms may occur. Therefore, alkaline substances cause deeper and more serious damage to tissues than acidic substances.
In order to prove that low concentrations of ammonia in the air are also harmful and harmful to human health, experts monitored workers working in an indoor environment with a concentration of 3~13 mg/m3 for 8 hours, 10 people in each group, and compared them with healthy people who were not exposed to ammonia
Source of ammonia in the air
1. Mainly from concrete admixtures used in building construction
Especially during the winter construction process, concrete antifreeze with urea and ammonia as the main raw materials is added to the concrete wall. These admixtures containing a large amount of ammonia are reduced to ammonia in the wall with the change of environmental factors such as temperature and humidity and are slowly released from the wall, resulting in a large increase in the concentration of ammonia in the indoor air.
2. Additives and whitening agents in interior decoration materials
Ammonia in indoor air can also come from additives and brighteners in decoration materials. However, this pollution has a relatively fast release period and will not accumulate in the air for a long time, and the harm to the human body is correspondingly smaller.
Limits of the AMMONIA standard in indoor air
Due to the high level of development of the building materials industry, there are few problems in other countries in this regard, and there are no clear relevant regulations. Indoor ammonia pollution is also a special situation in China recently. So far, there are no clear standards for ammonia in the indoor air of office buildings and homes in our country. At present, the indoor environmental testing department mainly has the following two reference standards:
1. "Hygiene Standards for Barbershops and Beauty Shops" in the health standards for public places formulated by the Ministry of Health in 1996
Because ammonia is often used in barbershop operations, the state stipulates that ammonia should not exceed 0.5 mg per m3 of air. At present, most of the indoor air testing in office buildings and homes is based on this standard.
2. The "Hygiene Standard for the Design of Industrial Enterprises" issued by the state (TJ36-79)
It specifies the maximum permissible concentration of harmful substances in the atmosphere of residential areas for ammonia in the air, and the controlled concentration of ammonia in the air should not exceed 0.2 mg per m3 of air.