Irritate the respiratory system and cause coughing, throat irritation and uncomfortable sensations in the chest.
Reduce lung function, leading to more rapid and shallow breathing that may limit a person's ability to engage in vigorous activities.
Heighten sensitivity to allergens such as pet dander, pollen and dust mites that commonly trigger asthma attacks, leading to more doctor and emergency room visits and greater use of medication.
Inflame the lung lining. Typically, damaged cells are shed and replaced much like skin peels after sunburn, but studies suggest that repeated inflammation over long periods of time can result in permanent scarring and loss of lung function.