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Atmospheric Aerosol


:: Section 1

Have you ever thought about what is in the atmosphere that we live in? Anything in addition to O2, N2, CO2 and water vapor? Indeed, there are many tiny aerosols in the atmosphere that affect our life, although we often do not sense and realize their existence.

The atmospheric aerosol is a complex and dynamic mixture of solid and liquid particles from natural and anthropogenic sources. The natural background aerosol is present in the absence of human activity, while the urban aerosol is dominated by anthropogenic sources. In both cases, primary particles are continuously emitted into and secondary particles are formed in the atmosphere. The atmospheric aerosol has a profound effect on our lives. It affects global climate, local weather, visibility, and personal health. An extreme example is the London smog disaster in 1952, which caused thousands of deaths primarily due to pneumonia, bronchitis, tuberculosis, and heart failure.

In the following sections, we will explore the sources of the atmospheric aerosol, their characteristics, how they are formed and removed, and how they influence our life (climate, health, etc). Finally, we will learn to estimate the effect of atmospheric aerosol on visibility.

Primary particles: particles that are introduced directly into the atmosphere
Secondary particles: particles that are formed by chemical reactions in the atmosphere (e.g. gas-to-particle conversion)


Environmental Engineers American Academy of Environmental Engineers
Chemical Engineers American Institute of Chemical Engineers
AGU American Geophysical Union (Atmospheric Sciences Section)
NIEHS National Institute of Environmental Health Sciences

Valuable Reading:

  • W. C. Hinds, Aerosol Technology, 2nd Edition, Wiley Interscience
  • S. Pandis and J. H. Seinfeld, Atmospheric Chemistry and Physics: Form Air Pollution to Climate Change, 2nd Edition, John Wiley & Sons
  • Finlayson-Pitts, B. J. and Pitts, J. N. J. Chemistry of the Upper and Lower Atmosphere. Academic Press: New York, 2000