Study On The Change Law Of Indoor Pollutant Concentration In College And Universities

The problem of air pollution has been widespread concerned around the world at present.We must not only attaches great importance to the outdoor air pollution treatment,pay more attention to indoor air pollution control.Obviously the good indoor air quality is vital to human body health.‘Indoor'is different use function of building enclosure,including homes,schools,hospitals,factories,commercial buildings,etc.Colleges and universities is an important part in college students'study and life,it has typical construction characteristics and ventilation characteristics.The research of indoor air quality of school has more realistic significance.This paper systematically analyzes the sources of indoor air pollutants and spread,induces the affecting factor on the changes of indoor pollutants.I perform real-time monitoring to the temperature and humidity?concentration of CO₂?PM_2.5.5 and PM₁₀?formaldehyde?VOCs of the classroom?office?dormitory in a university at xi'an in October2016 to January 2017.Analyze quantitative change orderliness of each parameter by a mass of experimental data.The results showed:?1?Under normal weather in autumn and winter,indoor temperature and humidity before and after the heating period show significant negative correlation relationship;Because of briefly indoor ventilation in the classroom before 8:00AM and 14:00PM,different period of indoor temperature and humidity changes differently.?2?Concentration of CO₂ overweight significantly in the classroom,as 5 times as the highest standard 1000 PPM.Dormitory slightly higher than the standard values;Office for the per capita area is larger,CO₂ concentration is lower than the standard values.?3?Outside window closed during monitoring,indoor and outdoor concentrations of PM_2.5.5 and PM₁₀0 are showing a significant positive correlation.During the monitoring,The concentration of indoor PM_2.5.5 average 120 ug/m³,but the highest can amount to 388 ug/m³,Indoor PM₁₀concentration is 2%above the secondary standard,and more than 68%level standard;Indoor PM_2.5.5 and PM₁₀0 daily average concentration ratio is 0.9.Rain,building orientation,building height all has influence to indoor PM_2.5.5 and PM₁₀.?4?The indoor concentration of VOCs and formaldehyde is far lower than the standard values because of the buildings in this school have long time,far more than formaldehyde concentration,VOCs release cycles.Using ANSYS software to make numerical simulation of the temperature field?velocity field?spread of CO₂ concentration?concentration of PM_2.5.5 under the condition of natural ventilation in the classroom to analyze the distribution orderliness.Simulation results show that:Under the condition of natural ventilation in the classroom temperature along the outside window to the door in horizontal gradient increasing.Around the body temperature is the tallest of the classroom,but does not affect the overall space temperature distribution.Different ways of natural ventilation directly affect the indoor air distribution,it makes CO₂diffusion degree,the distribution of PM_2.5.5 concentrations vary significantly.When the wind speed increases,PM_2.5.5 in indoor propagation speed faster,Indoor PM_2.5.5 concentrations increased;along outdoor PM_2.5.5 concentration increasing,the indoor PM_2.5.5 concentration increases,but the air PM_2.5.5 volume fraction is very small,indoor PM_2.5.5 concentration change trend is smaller.