Aerosol have both positive and negative influences on human health. On the positive side, they represent a means of delivering an active pharmaceutical ingredient directly into the lungs. On the negative side, aerosol in the urban environment represent a route for the transfer of harmful chemicals into the body. In the environment, the concentration of particles with diameter 2.5 µm or less and 10 µm or less (PM2.5 and PM10 respectively) are used to assess the air quality. Inhalation of particulate matter is associated with an increase in the prevalence of lung diseases such as asthma and can lead to further lung damage and premature death. The location of deposited particulate matter within the lungs can significantly affect the subsequent effects on the body.
Targeted delivery of drugs to certain regions of the lung, for instance, may increase the efficacy of inhaled medication. A thorough understanding of the changing size distribution of an aerosol is necessary to know where particles will preferentially deposit and how that location may be modified.
Figures © 2014 James Davies