A sampling instrument employing @[email protected] for the @[email protected] of particulate matter. Common types are:
  1. the midget impinger employing @[email protected] in \(1-10\ \text{cm}^{3}\) water,
  2. the standard impinger employing @[email protected] in \(75\ \text{cm}^{3}\) water and
  3. dry impingers.
Impingers are also suitable for sampling certain gases and vapours.
PAC, 1990, 62, 2167. (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2196 [Terms] [Paper]