Aerosols, health and drug delivery
A key to understanding the impact of aerosols on human health is to understand how they are transformed as they are inhaled and exhaled into the lungs. In the humid environment found within the respiratory tract, water vapour can condense on inhaled particles leading to growth in size. This can influence their depth of penetration into the lungs, with smaller particles penetrating deeper.
The targeted delivery of drugs to the lungs may be enhanced by altering their response to a humid environment. Further, the transmission of airborne viruses, such as the influenza virus, may be influenced by the humidity changes on exhalation and inhalation and it has been suggested that this could partly explain the seasonable variability in influenza rates.