Formaldehyde is a kind of gas harmful to human body, in life formaldehyde exceeds the standard is mostly seen in newly renovated housing, new furniture, formaldehyde has great harm to the body, the main harm and clinical symptoms are as follows: 1, respiratory system, inhalation of air containing formaldehyde will feel poor breathing, cough, chest tightness, long-term exposure may cause chronic pneumonia, lung function decline; 2, eyes, eye conjunctiva is more sensitive to formaldehyde, long Contact will appear dry eyes, tears, photophobia and other symptoms; 3, immune system, long-term inhalation of formaldehyde can damage the immune system, resulting in impaired immunity, patients are prone to recurring colds, fever and other symptoms, and even lead to the occurrence of tumors, especially leukemia, lymphoma, etc.; 4, nervous system, inhalation of formaldehyde can lead to damage to the nervous system, patients appear dizziness, fatigue, insomnia, drowsiness and other symptoms.