Which device is used to sample gases rather than particulate matter?

Impingers are specialized devices used for the collection of gaseous samples in various environments, including atmospheric monitoring and industrial emissions testing. They work by drawing the gas through a liquid in which specific compounds can dissolve, allowing for effective sampling of gases rather than particulates.

This process enables the analysis of gases in a manner that captures their chemical composition accurately, making impingers essential for studies in air quality, chemical engineering, and environmental science.

Other options, such as electrostatic precipitators and filter samplers, are primarily designed to capture particulate matter. While traffic flow meters serve a different purpose altogether, focusing on traffic data collection rather than air sampling, impingers are specifically utilized in scenarios requiring gas sampling, clearly positioning them as the correct choice in this context.