Joyce So, BSc
Despite growing concerns about air pollution, environmental tobacco smoke, and actions taken to reduce them, the incidence of asthma in North America has continued to rise since the 1970s.1,2 It is estimated that about 4 to 5% of the general population suffers from asthma.1 Asthma is a chronic inflammatory disease of the airways triggered by allergens and other stimuli, which lead to episodes of bronchial hyper-responsiveness and obstruction of airflow. Common signs and symptoms of asthma include recurrent wheezing, coughing, difficulty breathing and chest tightness. These symptoms often occur or worsen at night, during exercise, or in the presence of viral infection and common allergens such as dust, pets, pollen and smoke.
In the elderly, studies have shown that advanced age, male gender, parental history of chronic airway disease or hay fever, history of childhood respiratory illness, and environmental tobacco smoke exposure are all risk factors for developing asthma.1 In addition, various studies have established a clear association between bronchospasmic exacerbation and air pollution, with increased incidence of obstructed airways and hospital emergency department admissions for asthma in polluted, urban regions.