maximum emission concentration

in atmospheric chemistry
https://doi.org/10.1351/goldbook.M03763
Standards for maximum concentration of air pollutant emission from stationary or mobile sources.
Source:
PAC, 1990, 62, 2167. 'Glossary of atmospheric chemistry terms (Recommendations 1990)' on page 2200 (https://doi.org/10.1351/pac199062112167)