Environmental Health and Toxicology

Nicotine is a potent parasympathomimetic alkaloid and a stimulant drug. In particular, it is both a stimulant and a relaxant. It causes a release of glucose from the liver and adrenaline from the adrenal medulla thereby causing stimulation of nerve impulses and muscle relaxation.
Nicotine also produces adverse fetal effects. It is likely that hypoxia, undernourishment of the fetus and direct vasoconstrictor effects on the placental and umbilical vessels play a role.
Therefore, the correct answer is option D.

Polycyclic aromatic hydrocarbons or PAHs are a group of powerful cancer-causing chemicals found in cigarettes that can damage DNA and set cells down the road to becoming tumours. PAHs tend to damage particular sections of DNA. We know that PAHs contribute to lung cancer in smokers because DNA damage can be seen at these sections in patients.  One PAH compound, benzopyrene, is notable for being the first chemical carcinogen to be discovered (and is one of many carcinogens found in cigarette smoke). Its consequences are so bad, even if the woman exposed to PAH pollution during pregnancy, then there is adverse birth outcomes including low birth weight, premature delivery and heart malformations, lower IQ and asthma. Cord blood of exposed babies shows DNA damage that has been linked to cancer.

Smog contains pollutants like ozone, nitrogen oxides, and particulate matter, which are primarily respiratory irritants that damage the lungs.

Emphysema is a progressive, incurable chronic lung infection. The air sacs or the alveoli are destroyed and oxygen uptake is restricted due to the loss of elasticity of lung tissue.
Thus, the correct answer is option (C), 'Emphysema'.

Smoking is a practice in which a substance is burned and the resulting smoke breathed in to be tasted and absorbed into the bloodstream.
Emphysema is a form of chronic lung disease, usually caused by smoking.
Bronchitis is caused by tobacco smoke, dust, fumes, vapors and air pollution.
Changes in lung tissue begin when one inhale cigarette smoke.
Therefore, the correct answer is option D.

A substance that causes cancer is called a carcinogen. Cigarette smoke contains more than 4,000 chemicals out of which 43 are carcinogenic. Some of the carcinogens are nicotine, formaldehyde, benzene, carbon monoxide, etc. Most of the cigarette smoke remains in the lungs. This smoke damages the lung walls causing cancer. Thus the correct answer is option B.

Addiction is a phenomenon in which there is physical or psychological need to do, take or use something. The various addictions are smoking, chewing pan, chewing gutkha, alcohol, etc. Out of these addictions, the most harmful addiction for the respiratory system is smoking. It causes respiratory diseases like bronchitis, emphysema, laryngitis, breathlessnes, lung irritation. Its continuous use also causes permanent damage to the alveoli of the lungs. Nicotine is the addictive drug which is used in cigarettes.  

Drinking arsenic-rich water over a long period results in various health effects including skin problems (such as color changes on the skin, and hard patches on the palms and soles of the feet), skin cancer, cancers of the bladder, kidney and lung, and diseases of the blood vessels of the legs and feet, and possibly also diabetes, high blood pressure and reproductive disorders.

The ash can cause respiratory problems for young children, the elderly or those already with respiratory ailments.

Polycyclic aromatic hydrocarbons are a group of chemicals that are formed during the incomplete burning of coal, oil, gas, wood, garbage or other organic substances, such as tobacco and charbroiled meat.
They are the carcinogenic or cancer-causing substance in the tobacco smoke.
Therefore, the correct answer is option B.

Smoking is associated with significant morbidity and mortality. Smoking still remains one of the leading causes of preventable death. Smoking has the dubious distinction of affecting all the systems from head to foot. Cigarette smoking causes many types of cancer. It also increases the risk of cardiovascular diseases. Exposure to tobacco smoke during pregnancy can lead to delivery complications and increase the risk of health problems in the newborn. Quitting smoking significantly reduces the health risks caused by exposure to tobacco smoke. 

Tobacco (Nicotiana tabacum) belongs to family Solanaceae, is a silent long term killer can be consumed in a variety of ways like smoking, chewing, sniffing etc. Nicotine is a highly poisonous substance found in tobacco that increases pulse rate and blood pressure. It also increases stomach acidity, which is accompanied by a lack of appetite. Over time, tobacco users can look forward to such serious risks as narrowing or hardening of the arteries, respiratory infections, emphysema, stomach ulcers, chronic cough, and cancer of the mouth, throat, and lungs.