Final answer:
Asthma symptoms can be influenced by environmental factors, such as allergens, air pollution, and temperature changes. High levels of pollution in certain regions can contribute to higher rates of asthma and related diseases.
Step-by-step explanation:
Asthma is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. This causes swelling and narrowing of the airways, often accompanied by excessive mucus production. The severity of a patient's asthma symptoms can be influenced by environmental factors. For example, exposure to allergens, air pollution, cold air or a sudden change in temperature, and exercise can trigger asthma attacks. Some regions with high levels of pollution have higher rates of asthma and related diseases.