Research on Pollutant Control and Thermal Environment Improvement in Underground Catering Spaces: A Case Study of the Catering Zone in a Commercial Complex

Air-conditioning and ventilation systems are conventional approaches to improving indoor thermal environments and removing pollutants in underground catering spaces. However, unsuitable system design leads to a degraded thermal environment and aggravated pollutant dispersion. This study combines onsite measurement and numerical simulation to investigate the optimization of entrance air curtains, exhaust air flowrates, and air-conditioning system in underground catering spaces. The onsite measurements revealed that average temperatures in the catering spaces ranged from 24.5 to 26.9 °C in summer and from 20.2 to 26.3 °C in winter, exceeding thermal comfort ranges in most areas. Additional aspects include the accumulation of contaminants, an ineffective entrance air curtain, and upward pollutant migration. Simulation results revealed that optimizing the entrance air curtains created a temperature difference exceeding 0.90 °C at the entrance and reduced PAH concentration in the semi-contaminated zone by over 96.0%. Adjusting the exhaust air flowrate enhanced the PAH removal but had limited influence on temperature. Adjusting air-conditioning parameters reduced entrance PAH by 99.7% and lowered the overall temperature and PAH concentration by 14.40% and 9.91%, respectively. Under a comprehensive optimization scheme integrating all three measures, airflow was directed from the clean zone to the contaminated zone. This scheme achieved average temperature reductions of 7.34% in summer and 13.58% in winter, reversing the PAH dispersion pathway and eliminating PAH in the semi-contaminated zone. The proposed scheme provides a practical engineering solution for thermal environment improvement and pollutant control in underground catering spaces, and offers a reference for the design of similar projects.