Radioactive materials are also found in cigarette smoke; polonium is the most common. Some authorities believe that cigarettes are our greatest source of radiation. A smoker of one and a half packs per day may be exposed to radiation equal to 300 chest x-rays a year. Radiation is a strong aging factor. Acetaldehyde, a chemical released during smoking, causes aging, especially of the skin, as it affects the cross-linking bonds that hold our tissues together.

Cigarette smoking causes three primary degenerative-disease-producing effects: 1) irritation and inflammation; 2) free-radical generation; and 3) allergy-addiction. It is clear that cigarette smoke is a constant and chronic irritant to the body tissues, most specifically the oral cavity and respiratory tract. The polluting effect from cigarettes results less from nicotine than from the thousands of chemicals, including hundreds of poisons and carcinogens, contained in the smoke and tar. Supporting the nicotine addiction without the smoke (by using chewing tobacco, snuff, or nicotine gum) will reduce many of the undesirable respiratory effects of cigarettes. Cigarette smoke is a potent free-radical generator, also primarily a result of the many chemical irritants. And tobacco users exhibit the classic allergy-addiction picture. Studies testing smokers and nonsmokers in a variety of ways have shown that tobacco is a common allergen. Smoking causes irritation and many symptoms; stopping smoking causes cravings and withdrawal symptoms, so that smoking is needed for relief from the withdrawal. The ups and downs are associated with the chemical release of adrenal hormone and endorphins, such as that seen in allergies.

The main risk factor is the number of cigarettes smoked over time. "Pack years" is a common measurement in medical lingo. Someone who smoked one pack per day for 15 years and then two packs per day for 20 years would have 55 pack years, which is fairly high; even 20 pack years will increase the risk of many chronic problems, chiefly lung disease (bronchitis and emphysema), lung cancer, and heart disease. Smokers have twice the risk of death prior to age 65 than nonsmokers, and there is an average reduced longevity of 5–10 years for smokers, varying from lighter to heavier users. For shorter-term problems, such as bronchitis, smoking more than 25 cigarettes per day is associated with a high risk and smoking between 10 and 25 per day with a moderate one; smoking fewer than 10 cigarettes daily poses a low risk. The length and depth of inhalations also contribute to nicotine and tar intake.

There are also different levels of addiction. Least addicted are those who smoke only socially—at parties with friends—and usually only during certain parts of the day or week. They may smoke primarily for psychosocial or image reasons. Next are those who smoke in response to stress, mainly at work. They may stop and start. These first two smoking types are usually less addicted than heavier smokers, and it is easier for them to cut down or stop. The third type of smoker is the more serious, all-day-long smokers who have a fairly strong physical and psychological addiction; for these people, going more than an hour without nicotine causes the onset of withdrawal symptoms, such as irritability, anxiety, or headache. Often, the psychological influences lead to more frequent smoking of cigarettes than even the physical needs require. The extreme, "graduate" level smoker is the "chain smoker." He or she puffs nearly constantly, usually consuming three packs or more a day, and is strongly addicted. The latter two types often need medical and psychological support unless some special circumstance or divine intervention motivates them to stop immediately. Specialized stop-smoking programs are often needed, and even these are only sometimes helpful. Currently, about a third of adult men and women smoke in the United States. Between 10 and 20 percent of previous smokers have quit, leaving only 40–50 percent of adults who have not been regular smokers, and even most of them have at least tried cigarettes. But now by popular demand, from medical and social support, over 1 million smokers of the 50 million in the United States are stopping yearly, and they will immediately begin to lower their cancer and cardiovascular disease risks as well as reduce the negative effects on their lungs and other tissues.

Contrary to current marketing hype about low-tar, low-nicotine cigarettes, there are no safe cigarettes. Some of the newer "lights" may be even worse than regular cigarettes. Users inhale more deeply and smoke more in order to is satisfy their nicotine needs. Unless they have a low ratio of tar to nicotine, there are more risks posed by the increased chemical tars in the cigarettes. More carbon monoxide, hydrogen cyanide, and nitrogen gases are consumed with many of these low-nicotine cigarettes, and this can increase the oxygen deficit, heart disease, and lung damage associated with smoking. What smokers really need are high-nicotine, low-tar cigarettes, so that they need to smoke less to get their nicotine and have less exposure to the more carcinogenic, destructive tars. Even better will be ways to get nicotine to the blood without smoke. Nicotine gum works well, nicotine skin patches and nasal sprays are being researched, and soon there may be capsules or tablets to satisfy the craving. They will still be hazardous to our health but much less so than cigarettes, and will clearly get rid of pollution and secondary smoker risks.

What Are the Risks of Smoking?
Cigarette smoking probably has more harmful effects than any other commonly used drug, and affects more organs and tissues than most others. The total destructive nature of this one drug in the worldwide population is surpassed by no other, even though there are many drugs for which one dose is much worse than one cigarette. This is because it is so addictive and people use it so frequently for so long.

Cardiovascular disease (CVD) is one of the biggest concerns with tobacco use, both because of the direct effects of nicotine on the circulatory system (irritation and increased atherosclerosis) and the effects of other agents, such as carbon monoxide in inhaled smoke, which displaces oxygen. Carbon monoxide reduces the delivery of vital oxygen, our key life force, to all of our cells. Even low-tar cigarettes have high levels of carbon monoxide. Because of reduced oxygen delivery, our body makes more red blood cells (polycythemia), which can thicken the blood and further slow the circulation.

The CVD problem is primarily responsible for the decreased life expectancy associated with smoking, even more so than lung cancer, which usually results from 20–30 years of use. Circulatory effects start immediately and precipitate the development of CVD, mainly by increasing blood fats and blood pressure. Remember, the three primary contributors to CVD are smoking, hypertension, and high cholesterol, and smoking itself increases the incidence of the other two. Nicotine particularly lowers the level of the protective HDL cholesterol while increasing the supposedly destructive LDL cholesterol. It decreases circulation, especially of the hands and feet, and increases peripheral vascular resistance, so that the heart has to work harder with every beat. These factors contribute to the commonly elevated blood pressure of smokers. Nicotine’s effect on increasing platelet aggregation leads to more cases of cerebrovascular accidents (CVAs), or strokes, and myocardial infarctions (MIs), or heart attacks. Diabetics who smoke are at a very high cardiovascular risk, as nicotine increases blood fats and blood vessel effects and may increase insulin needs.