particle size distribution in atmospheric chemistry

The size of the liquid or solid particles in the atmosphere usually extends from $> 0.01$ to $< 100 µm$ in diameter. In the earth's atmosphere the distribution function which describes the number of particles as a function of diameter, mass or surface area of the aerosol can be determined reasonably well with modern instrumentation.

Source:

PAC, 1990, 62, 2167 (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2205