**3. Environmental and occupational triggers of asthma**

The purpose of this section is to review indoor air pollution factors that contribute to asthma exacerbation, not controlled symptoms and difficult to treat disease. Its important to note that we spend most of the time in the indoor environment which makes this environment the most susceptible to this patient population, and most of the time very difficult to control. When we are dealing with a difficult to treat asthma patient, we need to have a good sense of the patient surroundings such as work, home and most visited places during the day. Analysis of time exposure with symptoms is important, to down-regulate possibilities and get to the causative factor. The steps to establishing causative and effect relationship between exposures is a complicated and essential component in management patients with strong environmental effects. Discussion will be made separating indoor with outdoor environmental factors, as well most recognized causative agents.
