Abstract: The paper presents a study of the plasma characteristics with non-local properties in an atmospheric-pressure microdischarge generated in a helium flow. Using a wall probe, the plasma parameters were determined: temperature of the main group of electrons; density of metastable atoms and plasma. The impurity content was also assessed, n the plasma-forming gas. Additional studies were conducted using optical spectroscopy. A comparative analysis of two methods for determining impurities in buffer helium was conducted. Optical spectroscopy allows one to determine more chemical elements in plasma,,,, and, but not under all discharge conditions. It is shown that this discharge cell can act as an independent PLES analyzer for determining the composition of a gas mixture at atmospheric pressure, and does not require maintaining a high vacuum in the detector area.