The chemicals in cigarettes are mainly dry tobacco, which has been chemically treated with many added ingredients. The smoke of a lit cigarette contains about 4,000 chemicals, many of which are toxic, mutagenic and thousands of carcinogens. Everyone knows that smoking is harmful to health, cigarette smoke contains more than 4,000 chemical components, nicotine stimulates the central nervous system, increases heart rate, increases blood pressure, and has a very high addictive; tar in the filter adheres to the brown, it is inhaled with the smoke to the alveoli, and gradually absorbed, tar contains a large number of toxic substances, such as formaldehyde, arsenic, cyanide, benzene, toluene, carbon monoxide etc. All these toxic substances can interfere with the function of red blood cells to carry oxygen, causing hypoxia in the body. The relationship between smoking and lung cancer has become more popular with the promotion of scientific knowledge. Asthma is also a common disease in respiratory medicine, so what is the relationship between smoking and asthma? The results of a study published in 2006 by Finnish pulmonologists first showed that smoking predisposes to asthma, and that women in particular have a significantly greater risk of developing asthma from smoking than men. The results of that two-year follow-up study showed that smokers had a 33% greater risk of developing asthma than nonsmokers. In addition, those who quit smoking one year ago still had a 49% higher risk of asthma than nonsmokers, suggesting that smokers are still at risk for asthma years after they quit. The study also showed that women who smoked were more likely to develop asthma. The risk of asthma was 140% higher in women who smoked and in women who quit before 1 year ago than in nonsmokers. A recent research project conducted in Tasmania, Australia over a 40-year period is said to have confirmed a long-held belief that smoking triggers asthma, and that smoking can contribute to worsening asthma in adults, and that smoking in mothers can cause asthma in children. Smoking induces asthma because of the harmful components of tar, nicotine and cyanuric acid that were mentioned earlier. Nicotine and other substances act on the vegetative nerves and can stimulate the vagus nerve and cause bronchospasm. Tar can cause proliferation and mutation of the bronchial mucosa epithelium. Cyanuric acid damages the bronchial mucosa epithelium and its cilia, which increases mucus secretion from the bronchial mucosa, increases airway resistance, weakens the purifying function of the lung and cilia activity, and reflexively causes bronchospasm. Therefore, smoking can directly and indirectly cause bronchospasm, thus triggering the onset of asthma. If you live or work with a person who smokes, you can get the same harm as the smoker even though you never smoke. Therefore, both active and passive smoking can cause asthma attacks. Many studies have also demonstrated the association between asthma and smoking, with 8 out of 10 asthma sufferers saying that cigarette smoke makes their asthma worse and worse. Despite this, 15 to 20 percent of people with asthma still indulge themselves in the bad habit of smoking, even though it makes their asthma worse. What about passive smoking when the dangers of active smoking are so great? Don’t think that just because you don’t smoke, you are safe from those harmful ingredients. Even if you hate smoking or do not smoke, you can still inhale this smoke, for example, other members of your family smoking; your colleagues at work, your boss smoking; at parties, bars, entertainment venues, public places where other people smoke, you are in such an environment, have to be subjected to smoke. Some into had said: “other people’s smoking habits, but also the disaster of your life”. Therefore, asthma patients should not smoke, those who already smoke should quit, and those who do not smoke should not work and study in smoky environments. The incidence of asthma in children is also increasing, and research is being conducted on asthma and smoking in children. Passive smoking has been shown to cause decreased lung function and airway hyperresponsiveness in children. Approximately 7.5% of childhood asthma or lower respiratory tract disease with wheezing symptoms is caused by smoking by the child’s mother. A survey of 10,000 children in the UK in 1996 found that 7/10 children who smoked made their asthma worse or had an asthma attack; 1/3 of the children lived with a smoker, and if the child’s mother smoked more than 10 cigarettes a day, her child was 2 times more likely to have asthma than the child of a non-smoking mother. Children whose parents smoke are more likely to develop asthma than children whose parents do not smoke. The situation is worse if his/her mother is a smoker, because many children spend more time with their mothers than with their fathers; a child whose parents both smoke is more common to suffer from chronic cough and phlegm, and such a child inhales the equivalent of 60 to 150 cigarettes of nicotine per year. There was a study of 169 school children to clarify the relationship between passive smoking and maximum expiratory flow rate (PEFR), bronchodilator use, and respiratory symptoms. The findings showed that, in general, children with asthma had a slightly lower morning PEFR than children with cough only. Relatively few of all children surveyed had passive smoking in the home, accounting for only 11% of the children with asthma group and 14% of the cough-only group. The number of males was 61% in the asthma group and the same number of males and females in the cough only group. PEFR in the morning was 43.9 L/min lower in those with passive smoking in the home compared to those without passive smoking, and in the same children, passive smoking decreased PEFR by 41.9 L/min compared to pre-passive smoking. similarly, PEFR in the evening was lower in asthmatic children with passive smoking in the home. In addition, the investigators found that the decrease in PEFR increased with passive smoking. The asthma diary also revealed that cough and sputum were more common in children with asthma than in children with dyspnea and wheezing. About 20% of the children with asthma used bronchodilators. The presence of passive smoking on the previous day was an important factor in the use of bronchodilators, and the effect of continuous passive smoking within the previous 2 days was even greater. Although children in the cough group had a decrease in PEFR in both the morning and evening after passive smoking, the difference was not significant, and the decrease in PEFR was only 25% of that in children with asthma. The investigators concluded that passive smoking resulted in decreased PEFR, increased symptoms and increased bronchodilator use in children with asthma. The effect of passive smoking on PEFR was mainly chronic, but daily changes in passive smoking also affected symptoms, bronchodilator use, and PEFR, suggesting that passive smoking also has acute effects. The researchers concluded that preventing passive smoking is important for the health of children with asthma. In the case of asthma, smoking can be very damaging to the lungs. The airways of asthmatics are particularly sensitive to abnormal stimuli and are prone to constriction of the airways. The inhalation of smoke from cigarettes into the airways not only produces permanent constriction of the airways, making them narrow, but can also affect the function of sputum removal. This must result in chest tightness, difficulty breathing, incessant coughing and wheezing. This will be a daily affliction for years to come. If your child is an asthmatic and smokes in front of him or her or in a room with closed doors and windows, the child’s lungs will definitely be damaged, even more so than if he or she smokes himself or herself. Therefore, asthma patients should not ignore smoking. It is not easy to quit smoking, but for the sake of the health of the person with asthma or the child, it is important to make up your mind to quit smoking immediately.