Optimization of brick kiln technology and fuel type for cleaner production by comparative assessment of stack emissions and pollution dispersion modeling of selected brick kilns in Lahore

Brick kilns are among the major sources of air pollution in Pakistan, primarily due to their continued reliance on coal as the dominant fuel. Despite the adoption of modern zig-zag technology by many kilns, coal remains the primary fuel, contributing to substantial emissions. Lahore, one of the most polluted cities globally, hosts a huge number of brick kilns, which is among Pakistan’s least regulated industrial sectors. This study assesses and compares pollutant emissions and dispersion from conventional fixed chimney bull’s trench kiln (BK1), coal/biomass briquette-fuel brick kiln (BK2), and zig-zag kiln (BK3). Stack emissions were monitored using the Horiba PG-350 analyzer to measure carbon monoxide (CO), sulfur dioxide (SO 2 ), nitrogen oxides (NO X ), and particulate matter (PM 10 ). Results revealed that CO (6909, 1769, 2980 mg/Nm 3 ), SO 2 (6566, 1459, 2012 mg/Nm 3 ), and PM 10 (770, 150, 189 mg/Nm 3 ) exceeded Punjab Environmental Quality Standards (PEQS) for BK1, BK2 and BK3, respectively. Pollutant dispersion was modeled using the American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD) for 1-hour, 24-hour, and 1-year averaging periods to estimate ambient pollutant concentration and assess compliance with PEQS for ambient air quality and World Health Organization Air Quality Guidelines (WHO AQG). Predicted peak concentrations were highest for 1 hour, CO (349.41, 21.54, 97.54 μg/m 3 ), SO 2 (231.95, 18.29, 35.95 μg/m 3 ), NOx (2.18, 0.57, 2.29 μg/m 3 ), and PM 10 (20.24, 1.27, 3.45 μg/m 3 ) for BK1, BK2, and BK3, respectively. Modeling results indicated that ambient pollutant concentrations remained well below established regulatory standards. The study demonstrates the effectiveness of zig-zag kiln technology combined with coal and biomass briquette fuel in reducing emissions. It underscores the value of dispersion modeling as a predictive tool for assessing ambient air quality, ensuring regulatory compliance, and informing policy development. This study’s verdicts can help adopt smart and applicable action plans and build more precise pollution mitigation strategies at the source level. • Comparative analysis identified cleaner and more efficient brick kiln options. • AERMOD modeled pollutant dispersion for average hourly, daily and annual periods. • Dispersion modeling revealed ambient air concentrations of key air pollutants. • Predicted pollutant levels were below PEQS and WHO AQG limits. • Zigzag kiln and coal+biomass briquette fueled kiln showed better performance.