Comprehensive measurement of VOCs in a liquor-production cluster of China: OVOCs dominance, atmospheric environmental and health impacts.

Volatile organic compounds (VOCs) play a key role in atmospheric secondary formation. Unlike other high-emission industries, the characteristics and impacts of VOCs from liquor-production clusters remain poorly understood, despite the dominance of process-specific oxygenated VOCs. We conducted a stage-resolved investigation of ambient VOCs during representative production periods between 2023 and 2024 in a concentrated Moutai-flavor baijiu industrial cluster in Guizhou, China. The average TVOCs150 concentration was 251.78 ± 358.96 ppbv, dominated by OVOCs (91.63%), with alcohols (54.80%), acids (19.82%), aldehydes (10.33%), and esters (4.01%) as the major groups. OVOCs concentrations increased with advancing liquor production rounds, coinciding with rising ambient temperatures. On a daily scale, OVOCs peaked between 07:00 and 11:00, following the liquor-making operational schedule. Beyond these primary emission controls, photochemical formation made a non-negligible contribution to daytime OVOCs, shifting species dominance from brewing-derived ethyl acetate to ambient acetaldehyde. The OBM-MCM simulation estimated that 70.38% of secondary acetaldehyde formation was associated with the OH-initiated oxidation of abundant ethanol. Alcohols, aldehydes, and organic acids jointly contributed 77.73% of the ozone formation potential. Aldehydes (89.13%), glyoxal (80.38%) as the major contributor, dominated secondary organic aerosol (SOA) formation. Notably, acetic acid accounted for 45% of precipitation acidity, surpassing traditional inorganic acids. Health risk assessment further revealed that acetaldehyde exposure resulted in carcinogenic risks exceeding the U.S. EPA tolerable threshold (1 × 10-4). This study highlights the unique evolution and impacts of ambient OVOCs in brewing clusters, emphasizing that targeted mitigation strategies must address their specific environmental and health impacts.