According to a recent research conducted at the US Massachusetts General Hospital, children who live in homes where they are exposed to second-hand smoke miss more days of school than do children living in smoke-free homes. The research notes that these children have higher rates of respiratory illnesses caused by second-hand smoke.

Among children aged six to 11 who live with smokers, one quarter to one third of school absences are due to household smoking. The authors note that one-third of US children live with at least one smoker and more than half of those aged three to 11 have detectable levels of a blood marker for tobacco exposure. Second-hand smoke has been shown to increase incidence of ear infections and several respiratory conditions; school absenteeism is an accessible measure of serious illness in children.

Second-hand smoke, passive smoking or involuntary smoking, refers to the smoke emitted into the environment from smouldering cigarettes and other tobacco products between puffs and the smoke exhaled by the smoker.

Children exposed to second-hand smoke suffer more from respiratory infections like bronchitis and pneumonia, severe asthma, chest colds, ear infections and sudden infant death syndrome. Second-hand smoke can also cause lung cancer and cancer of the larynx (voice box) and pharynx (upper throat). It can even cause other health problems like heart disease, stroke and breathing problems. Half an hour of exposure to second-hand smoke can reduce blood flow in a non-smoker’s heart.

Second-hand smoke is considered more toxic than mainstream smoke, although people inhale it in a more diluted form. It contains much higher levels of many of the poisons and cancer-causing chemicals in cigarettes, like carbon monoxide, benzene, ammonia, cadmium, nitrosamines and polycyclic aromatic hydrocarbons (PAHs), which cause DNA damage among children.

Scientists have identified about 4,000 different chemicals in tobacco smoke. According to the International Agency for Research into Cancer and the European Network for Smoking Prevention, at least 80 of these chemicals could cause cancer. Many of the other thousands of chemicals are toxic and harmful to health, including carbon monoxide, hydrogen cyanide and ammonia.

Chemicals found in second-hand smoke harm almost every organ in the body — from causing major damage to human body’s blood network to causing diseases of the lungs and airways. Chemical deposits damage the surrounding cells and constrict the airways, making breathing more difficult.

The ability of haemoglobin to carry oxygen in the bloodstream is damaged by carbon monoxide and nitrogen oxide, thus reducing the levels of oxygen in bloodstream; this leaves the body’s organs starved of oxygen. Toluene can interfere with the development of brain cells as well as disrupt the insulating sheath that surrounds nerve cells, making them less efficient at carrying signals.

Children face a higher risk of the negative effects of second-hand smoke than adults because a child’s body is in the growing and developing stage. They breathe at a faster rate than adults. While adults breathe in and out approximately 14 to 18 times a minute, children’s respiratory rate is between 20 and 60 breaths per minute; newborns can breathe as high as 60 times a minute.

Children who spend one hour in an extremely smoky room inhale enough toxic chemicals to equal smoking 10 cigarettes. Babies whose mothers smoke during pregnancy weigh relatively less and are at an increased risk for cerebral palsy. Second hand smoke has been blamed for aggravating asthma in children while being responsible for thousands of new cases of asthma every year.

Children in smoking households experience more middle ear infections. Inhaled cigarette smoke irritates the Eustachian tube and the subsequent swelling leads to infections, which are the most common cause of hearing loss in children.

The problems caused by smoking do not stop at second-hand smoke. There is also third-hand smoke, or the toxic collection of gases and particles that cling to the smokers’ hair, clothing, cushions and carpets, which lingers long after second-hand smoke has cleared from a room. It consists of residual tobacco smoke pollutants that remain on surfaces and in the dust after smoking. More importantly, it reacts with oxidants and other compounds in the environment to yield secondary harmful pollutants.

For example, nicotine absorbed onto surfaces reacts with nitrous acid, an air pollutant found in burning tobacco, to form tobacco-specific nitrosamines, which are classified by the International Agency for Research on Cancer as human carcinogens.

Likewise, ozone, another indoor air pollutant, reacts with some 50 compounds in second-hand smoke to produce ultra-fine particles. The small size facilitates their uptake by the human body and distribution throughout the body to potentially sensitive target sites including the bone marrow, lymph nodes, spleen, heart, and central nervous system.

Smokers are not only damaging their health but that of their children as well. They should consider quitting in order to protect children from the dangers of second-hand smoke and providing them with smoke-free air to breathe.