地铁集中空调通风系统混合送风模式下污染物扩散机制

石斌; 王怀记; 陈智; 王芳; 刘华牛; 胡迅

doi:10.11847/zgggws1128069

地铁集中空调通风系统混合送风模式下污染物扩散机制

Mechanism of pollutant diffusion in subway environment with central air conditioning ventilation system under mixed air supply mode

摘要

摘要:
目的探讨地铁集中空调通风系统混合送风模式下污染物的扩散机制，分析集中空调通风系统对室内空气质量的影响。
方法随机抽取某城市4条地铁线20 % 的站点，对其集中空调通风系统和室内空气中PM_2.5、PM₁₀、细菌总数、真菌总数进行检测。
结果新风、回风、混风、送风污染物水平差异均有统计学意义（P均 < 0.05），送风污染物浓度均低于新风、回风、混风；室内空气检测结果显示，送风污染物浓度均低于站厅、站台层（P均 < 0.05）。站台层颗粒污染物水平均高于站厅层（P < 0.05），微生物水平差异无统计学意义（P > 0.05）。PM_2.5相关性分析结果显示，送风污染物水平与新风、混风污染物水平呈正相关；站厅层空气、站台层空气中污染物水平与送风污染物水平呈正相关；细菌总数相关性分析结果显示，送风与新风、混风细菌总数呈正相关，站厅层空气与送风细菌总数呈正相关，站台层空气细菌污染物与送风无相关性。
结论地铁集中空调通风系统可有效降低风源中的污染物浓度，对相对静态环境的站厅层室内空气改善较为明显，但对于相对动态的站台层室内空气则影响相对较小。

Abstract:
Objective To explore the mechanism of pollutant diffusion under mixed air supply by central air conditioning ventilation system and the influence of central air conditioning ventilation on indoor air quality in subway environment.
Methods Totally 4 subway lines′ 24 subway stations (6 for each line) with central air conditioning ventilation system in a city were randomly selected for detections on particulate matter ≤ 2.5/10 μm in aerodynamic diameter (PM_2.5/PM₁₀), total bacteria and total fungi in air samplings collected at various sites of ventilation system and subway environment.
Results There were significant differences among concentrations of detected pollutants in fresh air, return air, mixed air and supply air (P < 0.05 for all); the concentrations of the pollutants in supply air were all lower than those in fresh, return, and mixed air and significantly lower than those in indoor air samples collected at station hall and platform floor (all P < 0.05). The concentration of PM_2.5 and PM₁₀ in air samples collected at platforms were higher than those in samples collected in station halls (P < 0.05 for all); but there were no significant differences in colony forming units (CFU) of total bacteria and fungi (P > 0.05 for all). There were significant positive correlations among PM_2.5 concentration of supply, fresh, and mixed air and between PM_2.5 concentrations of supply air with those of air samples collected at station halls and platforms (P < 0.05 for all). There were also significant positive correlations among CFU of total bacteria for supply, fresh, and mixed air and between CFU of total bacteria for supply air and that for air samples collected at station halls (P < 0.05 for all); while, no significant correlation was observed between the CFU of total bacteria for supply air and that for air samples collected at station platform.
Conclusion The central air conditioning ventilation system can effectively reduce concentrations of pollutants in subway environment and the pollutant reduction for indoor air in station halls is more obvious than that for indoor air at station platforms.

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