Respiration consumes stored starch or sugar and ceases when reserves are depleted; ageing ensues, and the product dies and decays. 4.7.1 The influence of air supply on respiration Mortality from respiratory diseases is highest where there is little or no fresh air available for replacement. Many diseases spread through contaminated air within buildings or underground stations, such as tuberculosis and legionella pneumonia. Outbreaks of influenza and other respiratory infections are common in crowded living conditions with poor ventilation. Airborne particles generated by burning material such as wood or coal can lead to respiratory problems for people who live in these areas. Outdoor air quality has a significant impact on respiratory health. Polluted air contains substances that can irritate your lungs and trigger asthma attacks. Smoking increases your risk of developing lung cancer and heart disease. The main types of respiratory illness include: - Bronchitis: An inflammation of the bronchi, the tubes that carry air into and out of the lungs. It is usually caused by a virus or bacteria but may be due to some other causes such as chemical fumes or smoke. Symptoms include fever, cough, breathlessness, pain in the chest and fatigue. Chest X-rays and tests done during an exacerbation of the condition may show changes indicative of inflammation of the lungs. Asthma: A chronic disorder of the respiratory system characterized by recurrent attacks of shortness of breath, coughing, and wheezing.