Analyzing Occupational Factors Impacting Air Quality in Traditional Cafes of Tehran, Iran: A Study on PM2.5, PM10, and CO<sub>2</sub> Levels

Traditional cafes are indoor spaces with many suspended particles and toxic compounds in the air. This study aimed to investigate the air quality in terms of indoor and outdoor suspended particles of PM2.5 and PM10, and CO₂ in traditional cafes in Tehran. This descriptive study was conducted in 2019-2020 on 100 traditional cafes. The concentration of PM10 and PM2.5 in these cafes' indoor and outdoor air was measured using a Particle Mass Counter, and the concentration of CO₂ was measured by 535-TESTO (Testo SE & Co. KGaA, Lenzkirch). The data was analyzed using SPSS.22 (IBM, NY). The trend of changes in the concentration of suspended particles of PM10 and PM2.5 in hookah supply places in Tehran showed that teahouses had the highest concentrations of those particles compared to other studied places, i.e., traditional restaurants, hookah cafes, and traditional coffeehouses. The average concentrations of PM10 and PM2.5 inside the coffeehouses were higher than the threshold limits of the World Health Organization (WHO) guidelines for long-term effects. The long-term presence of these harmful compounds in the indoor air of traditional cafes can cause chronic exposure to their staff and adversely affect their health.