en تخصصي Special مقاله اصیل Original Article <div style="text-align: justify;">Introduction: Sulfur dioxide (SO2) is a major air pollutant with severe health and environmental impacts. Spray towers are widely used in flue gas desulfurization (FGD) systems; therefore, optimizing their operational parameters is crucial for enhancing SO2 removal efficiency.<br> Methods: This study investigated the effects of liquid flow rate (4&ndash;6 L/min), gas flow rate (105&ndash; 158 ft&sup3;/min), inlet SO2 concentration (60&ndash;120 ppm), nozzle type, and the number of nozzles on the removal efficiency of sulfur dioxide gas using a spray tower (1.38 m in height, 0.25 m in diameter). The experiments were designed using Response Surface Methodology (RSM) through Design-Expert software.<br> Results: The highest removal efficiency (96%) was achieved with the SS80 Berto nozzle, liquid flow rate of 6 L/min, gas flow rate of 105 ft&sup3;/min, three nozzles, and an inlet SO2 concentration of 60 ppm. Gas flow rate and inlet concentration negatively impacted efficiency, while liquid flow rate and the number of nozzles had a positive effect (P < 0.001).<br> Conclusion: Optimizing operational parameters, particularly nozzle type and liquid flow rate, significantly improves spray tower performance for SO2 removal.</div> Sulfur dioxide, Air pollution, Gas-liquid systems, Environmental monitoring 1 11 http://ehemj.com/browse.php?a_code=A-10-1-456&slc_lang=en&sid=1 Shaghayegh Eidani sh.eidani@sbmu.ac.ir 100319475328460022396 100319475328460022396 No Department of Occupational Health Engineering and Safety at Work, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran Somayeh Farhang Dehghan somayeh.farhang@gmail.com 100319475328460022397 100319475328460022397 No Environmental and Occupational Hazards Control Research Center, Research Institute for Health Sciences and Environment, Shahid Beheshti University of Medical Sciences, Tehran, Iran Davod Panahi davodpanahi@gmail.com 100319475328460022398 100319475328460022398 Yes Correspondence to: Health Promotion and Research Center, Research Institute for Health Sciences and Environment, Shahid Beheshti University of Medical Sciences, Tehran, Iran Alireza Rahmati Alirezarahmati@gmail.com 100319475328460022399 0009-0007-4579-574X No Department of Occupational Health Engineering and Safety at Work, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran Yaser Khorshidi Behzadi yaserkhorshidii@gmail.com 100319475328460022400 100319475328460022400 No Department of Occupational Health Engineering and Safety at Work, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran