Study On Indoor Air Environment Optimization Of Naturally Ventilated Dormitory Building In Heating Season

The indoor air environment of buildings affects the health and work efficiency of indoor personnel,and natural ventilation is the most economical and effective means to improve the indoor air environment.In the heating season with frequent outdoor smog,how to keep a good indoor air environment in naturally ventilated buildings has become a hot issue in the fields of architecture and environmental science in recent years.This study takes a dormitory building in Xi’an as the research object,and grasps the present situation and problems of indoor air environment through subjective and objective investigation.Through the experiments of natural ventilation,humidification and air purification,the air environment optimization measures of typical dormitories suitable for natural ventilation are explored.Potential toxicity analysis,subjective investigation and evaluation were adopted to evaluate the implementation effect of optimization measures.The main results are as follows:（1）In the heating season,the main indoor air pollutants in this dormitory building are CO₂ released by indoor human respiration and PM_2.5 entering the room from the outdoor atmosphere,and the pollution is serious,the air humidity is low,and the comfort of personnel is not high.Under the condition of natural ventilation,there are contradictions between indoor pollution control and comfort,and between indoor pollution control and outdoor pollution control.（2）In the heating season,when the outdoor temperature is 1-5℃,the wind is 0-1,and the outdoor air is polluted by PM_2.5,and the indoor living area is 17.2 m²,the window size is 1.1 X 0.6m,and the typical dormitory building with four people indoors,the best natural ventilation window opening modes are "unilateral ventilation-window opening 10cm" and "bilateral ventilation-window opening 1cm".While adopting the best natural ventilation mode,when the average outdoor concentration of PM_2.5 is less than or equal to 110 ug/m³ and the purified air volume of the purifier is 340 m³/h,the indoor concentration of PM_2.5 in a typical dormitory is less than 30 ug/m³,which can meet the relevant standards.When the humidification amount of humidifier reaches 650 mL/h,the indoor air humidity of typical dormitory is more than 30%of the standard requirement,which meets the requirements of personnel for humidity.（3）The comprehensive index evaluation of indoor air quality shows that indoor air is still slightly polluted only by natural ventilation measures;Taking the best natural ventilation and air purification measures can effectively improve the indoor air quality in the dormitory.Subjective evaluation shows that the subjective evaluation of indoor air quality and air humidity by indoor personnel is obviously improved and the proportion of people with bad symptoms is obviously reduced after the optimization measures are taken.