Second-hand smoke causes a range of illnesses, some of which are fatal. The effects of second-hand smoke are outlined below.
Long-term effects 
Second-hand smoke increases the risk of developing lung cancerin non-smokers by 20-30% Non-smokers exposed to second-hand smoke may have a 25-35%increased risk of having a heart attack Increases the risk of having a stroke in non-smoking men by 82% and in non-smoking women by 66% Second-hand smoke is a known trigger for asthma attacks. Even just one hour in a smoky atmosphere can lead to 20% deterioration in lung function Exposure to second-hand smoke during pregnancy is very dangerous for the unborn child, resulting in low birth weight or premature birth Second-hand smoke increases the risk of coughing, wheezing, bronchitis and pneumonia and result in reduced lung growth. Other health effects are middle ear disease and exacerbation of asthma symptoms. It is estimated that more than 17,000 children under five years of age are admitted to hospital every year in the UK due to symptoms related to second-hand smoke.
Immediate/short term effects Being in a smokey atmosphere for even a short period of time can result in: Shortness of breath Eye irritation Headache Cough Sore throat Dizziness Nausea