人呼吸时需吸入空气，在肺泡内氧气被摄取，然后排出含有高浓度二氧化碳及其它一些有毒、有害气体。研究发现，人 肺可排出 20 余种有毒物质，其中 10 余种含有挥发性毒物。因此，人们在拥挤、空气不流通的房间内，常感到眩晕、呼吸困难，严重者出现胸闷、出虚汗、恶心等，症状。另外，患有呼吸道传染病的病人，通过呼出气、喷嚏、咳嗽、痰和鼻涕等，可将病原体传播给他人。
When breathing, people need to inhale air, which takes up oxygen in the alveoli and then expels high concentrations of carbon dioxide and other toxic and harmful gases. Research has found that human lungs can excrete more than 20 toxic substances, of which more than 10 contain volatile toxins. Therefore, people often feel dizzy and have difficulty breathing in crowded and poorly ventilated rooms. In severe cases, symptoms such as chest tightness, sweating, and nausea may occur. In addition, patients with respiratory infectious diseases can transmit pathogens to others through exhalation, sneezing, coughing, phlegm, and nasal mucus.
二手烟雾
Second hand smoke
烟草在燃烧时，会产生尼古丁、焦油、氰氢酸等。尼古丁可兴奋神经，收缩血管，升高血压和减少组织血液供应，会通过增加心率提高氧消耗量，连续吸入尼古丁过多可使人丧生。焦油含多种有机化合物，其中含有微量苯并芘、苯蒽等物质，苯并芘具有较强的致癌作用。世界卫生组织公布的资料表明,65 岁以下男性 90/100 的肺癌死亡、75/100的慢性支气管炎和肺气肿的死亡是由于吸烟所致。
When tobacco is burned, it produces nicotine, tar, cyanuric acid, etc. Nicotine can stimulate nerves, constrict blood vessels, increase blood pressure, and reduce tissue blood supply. It can increase oxygen consumption by increasing heart rate. Continuous inhalation of excessive nicotine can cause death. Tar contains various organic compounds, including trace amounts of substances such as benzopyrene and anthracene, which have strong carcinogenic effects. According to data released by the World Health Organization, 90/100 deaths from lung cancer, 75/100 deaths from chronic bronchitis, and emphysema in men under the age of 65 are caused by smoking.