On May 31, is "world no tobacco day" is the theme of the 2007 no tobacco day "to create a smoke-free environment", aims to remind the public to know the harm of passive smokers, and environmental tobacco smoke.
Since the 1950 s, global has a large number of epidemiological studies confirm that smoking is the leading risk factors of lung cancer. In order to cause the attention of the international community for tobacco harm to people's health, suggested in November 1987, the world health organization will every year on April 7, as the "world no tobacco day", and in 1988 began to perform. Since 1989, the world no tobacco day to May 31 of each year.
Contains more than 1400 kinds of ingredients in cigarettes. Smoke smoke has more than 40 carcinogens, there are a dozen will material to promote the development of cancer, one of the biggest harm to human body is nicotine, carbon monoxide and various other metal compounds. A smoke contains nicotine is enough to kill a mouse. Cigarette smoke in the combination of a large amount of carbon monoxide with hemoglobin ability in 240-300 times larger than oxygen, seriously weakened the ability of red blood cells carry oxygen, therefore, smoking increased blood clotting, which easily cause myocardial infarction, stroke, cardiovascular diseases such as myocardial ischemia. More seriously, smokers also seriously hamper others health. The research results show that smokers smoke harm to others is greater than his own.
5月31日是 “世界无烟日”2007年无烟日的主题是“创建无烟环境”，旨在提醒公众认识烟草烟雾对被动吸烟者和环境的危害。
自20世纪50年代以来，全球范围内已有大量流行病学研究证实，吸烟是导致肺癌的首要危险因素。为了引起国际社会对烟草危害人类健康的重视，世界卫生组织1987年11月建议将每年的4月7日定为“世界无烟日”，并于1988年开始执行。自1989年起，世界无烟日改为每年的5月31日。
香烟中含有1400多种成分。吸烟时产生烟雾里有40多种致癌物质，还有十多种会促进癌发展的物质，其中对人体危害最大的是尼古丁、一氧化碳和多种其它金属化合物。一支烟所含的尼古丁就足以杀死一只小白鼠。香烟烟雾中大量的一氧化碳同血红蛋白的结合能力比氧大240—300倍，严重地削弱了红细胞的携氧能力，因此，吸烟使血液凝结加快，容易引起心肌梗塞、中风、心肌缺氧等心血管疾病。更为严重的是，吸烟者还严重妨碍他人健康。研究结果表明，吸烟者吸烟时对旁人的危害比对他自己还大。
