Research On The Influence Of Gas Micro Environment In Urban Underground Space On Human Cognitive Ability

The gas microenvironment in urban underground space has a significant impact on the physiological and psychological state of practitioners.The unhealthy gas microenvironment will cause short-term or long-term harm to human body,and even lead to occupational diseases.Subway workers are exposed to high carbon dioxide concentration for a long time,which affects people’s cognitive ability and leads to safety accidents.For a long time,many scholars have studied the influence of thermal environment and light environment on human cognitive ability,but the influence of gas microenvironment,especially carbon dioxide concentration,on human cognitive ability is rarely reported.Compared with other workplaces,urban underground space is characterized by poor ventilation,low oxygen concentration and high carbon dioxide concentration.Based on the influence mechanism of cognitive ability and combined with the characteristics of the gas microenvironment in urban underground space,this paper firstly established a set of cognitive ability evaluation system.By carrying out experimental studies on the changes of human cognitive ability under different carbon dioxide concentrations and temperatures,the numerical quantitative correlation between different carbon dioxide concentrations and temperatures and human cognitive level was obtained.Finally,the influence law of the gas microenvironment of urban underground space on human cognitive ability is obtained.The results are as follows:(1)In urban underground space,with the increase of temperature and carbon dioxide concentration,the thermal sensation of human body increases,while the sense of comfort,environmental perceived quality and self-cognition decreases.However,too high or too low temperature will reduce the subjective feeling value of human,and ultimately the level of human cognitive ability.Thermal comfort and self-cognition are most significantly affected by the environment,so the regression curves between them and cognitive performance are fitted respectively.The symptoms of sick building syndrome,such as lethargy,sleepiness,dizziness,fatigue and weakness,were gradually significant with the increase of temperature and carbon dioxide concentration,and could be used as an important indicator of cognitive ability.(2)By testing physiological parameters of the influence of gas microenvironment in urban underground space on human cognitive ability,the study found that with the increase of carbon dioxide concentration,human skin temperature and heart rate gradually increased,blood oxygen saturation and blood pressure showed a trend of decrease,and all physiological parameters were significantly correlated with task performance.(3)Cognitive performance decreased significantly with the increase of carbon dioxide concentration,and too high or too low temperature would also reduce cognitive ability.Since the four cognitive abilities are significantly affected by carbon dioxide concentration,the regression curves of carbon dioxide concentration and the performance of the four cognitive abilities and the total performance are fitted to obtain the quantitative relationship.