Lighting a cigarette in the cold weather may sound very enticing but your heart will not thank you for it. Smoking in any weather is hazardous but in winter even more. The cold air and smog affects the lungs and your smoking doesn t help. Smoking leads to swelling and narrowing of the lung airways causing breathlessness. The excess mucus in lungs passage and impairment of the lungs clearance system leads to a buildup of poisonous substances. This increases the risk of lung infections which begins with symptoms such as wheezing and coughing suggests Dr. Pankaj Sayal Consultant Pulmonology PSRI