## Wikipedia - Gęstość liczbowa (pl) particle concentration

in atmospheric chemistry
https://doi.org/10.1351/goldbook.P04423
Commonly expressed in several ways: mass concentration (usually as $$\unicode[times]{x3BC}\text{g}\ \text{m}^{-3}$$) or number concentration (number of particles $$\text{cm}^{-3}$$); modern instrumentation allows measurement of the number of particles as a function of size as well as the total number present in a given air volume. For atmospheric aerosols, this is a complex distribution for which diameters range from below $$0.01$$ to above $$100\ \unicode[Times]{x3BC}\text{m}$$; the particles making the highest contribution to the total @N04262@ are in the size range below $$0.1\ \unicode[times]{x3BC}\text{m}$$, those contributing most to the total surface area are in the $$0.1$$ to $$1.0\ \unicode[times]{x3BC}\text{m}$$ range, while those with the highest contribution to the volume or mass of the @A00176@ come from both the $$0.1$$ to $$1.0\ \unicode[times]{x3BC}\text{m}$$ and $$1.0$$ to $$100\ \unicode[Times]{x3BC}\text{m}$$ ranges.
Source:
PAC, 1990, 62, 2167. (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2181 [Terms] [Paper]