INTRODUCTIONEnclosed designated smoking areas (DSAs) and smoking zones are allowed in food-serving venues in Kazakhstan. Air quality in smoke-free food-serving venues, in venues with smoking throughout, in those with DSAs and those with smoking zones, is not fully understood.METHODSA cross-sectional study with aim to evaluate PM2.5 concentrations in the venues with mixed smoking was conducted from September to October 2017 in Almaty, the largest city of Kazakhstan. A total of 44 rooms within the selected 29 venues were evaluated: 100% smoke-free (5), non-smoking zones (7), smoking zones (7), non-smoking venues with DSAs (8), venues that allow smoking throughout (9), and DSAs (8). Real-time PM2.5 measurement was conducted by TSI SidePak AM510 Personal Aerosol Monitor and used to rank health-risk assessment using the Air Quality Index developed by the U.S. Environmental Protection Agency.RESULTSSmoke-free food-serving venues had moderate levels of air quality with mean PM2.5 of 26.2 μg/m3 while non-smoking zones inside venues that also permitted smoking had a mean of 56.5 μg/m3, corresponding to unhealthy air quality. Venues restricting smoking only to DSAs also had unhealthy air quality in non-smoking areas (mean PM2.5 = 87.6 μg/m3) while DSAs had hazardous levels of air quality (mean PM2.5 = 647.9 μg/m3). Smoking zones inside the venues and venues allowing smoking throughout had a mean PM2.5 of 180.3 and 182.0 μg/m3, respectively, ranking as very unhealthy. On average 3.5 persons were observed in DSAs with mean volume of 38.9 m3. Cigarette and/or hookah were the major source of PM2.5. The higher the smoker density the poorer the air quality in the venue.CONCLUSIONSHazardous level of PM2.5 due to tobacco products inside DSAs demonstrated the low efficiency of a smoking ban with exemptions. A complete smoking ban in food-serving venues should be in place to fully protect people from hazardous air quality conditions.