Occupational Asthma: Exposure to allergens and irritants in the work place may make someone's asthma worse. Work place exposures may also cause someone without asthma to develop the disease. Indoor air quality: Learn more about indoor air quality and asthma. Smoking and Asthma: Learn all about the effects of smoking and secondhand smoke on people with and without asthma, and find resources to help smokers quit. Environment: Learn how your environment, either indoors or out, can play a large part in your asthma symptoms. Find tips on building and remodeling for a healthier home.