What are the effect of first-hand and second-hand tobacco smoke on the human respiratory system? what are the effects of second-hand smoking on children and the unborn?

First-hand smoke, which is inhaled by the smoker. Second-hand smoke, which is the smoke either exhaled by a smoker or released from the end of a burning cigarette.

The effects of tobacco smoke on the respiratory system include: irritation of the trachea (windpipe) and larynx (voice box) reduced lung function and breathlessness due to swelling and narrowing of the lung airways and excess mucus in the lung passages.

since the levels of exposure to secondhand smoke are lower than in active smoking, the effects of secondhand smoke tend to be less severe. Non-smokers exposed to secondhand smoke commonly experience eye, nasal and throat irritation. Secondhand smoke may be responsible for causing the onset of asthma in adulthood, may contribute to increased airway wall thickness and poorer health outcomes. Research suggests that exposure to secondhand smoke may cause an elevated risk of developing chronic obstructive pulmonary disease (COPD), which is marked by permanent and progressive damage to the airways and airway sacs of the lung.

Secondhand smoke is extremely dangerous for babies. They're also more likely than other children to develop a range of lung and other health problems. It weakens their lungs, asthma, makes them more prone to ear infections, and doubles the risk of sudden infant death syndrome.

Some of the health conditions associated with being exposed to second-hand smoke whilst pregnant are a miscarriage, low birth weight, early birth, learning or behavioural deficiencies in your child, and Sudden Infant Death Syndrome