Showering in warm water opens the pores of the skin and permits a high rate of absorption of chlorine and other chemicals. In fact, the steam we breathe in while showering can contain up to 20 times the level of chlorine and other synthetic chemicals than tap water. Awesome Organics' Aquasana Shower Water Filter helps to filter out toxic chemicals found in tap water.
A latest report in the American Journal of Public Health linked chlorine to major increases in certain types of cancer and stated that "up to 2/3 of the harmful exposure was due to skin absorption and breathing while showering".
Inhalation of chlorine and chemical vapors is recognized to be a strong irritant to the tissues in our lungs and is suspected to be a primary reason of asthma and bronchitis.