| Today indoor air quality has been a strong concerned as the increase of atmosphericpollution and indoor pollution sources. The majority of people spent70%to90%of their timein indoor environment, the United States Centers for disease controlling said that the harmfulof indoor air pollution on human body more than outdoor air pollution, and others havepointed out that the indoor particulate air pollution accounted for76%of indoor air pollution,indoor particulate pollution seriously affect human health, therefore, analysis the variation ofthe concentration of indoor particles and controlling means have become an urgent problem tobe solved in HVAC field.In this paper, through theoretical derivation, the variation characteristics of indoorparticle concentration of pollutants and the parameters on the concentration of indoorparticulate matter were discussed in detail, including the indoor particle concentration, freshair volume, air exchange rate, infiltration rate, filter efficiency factor; combined with linearregression model, the linear fitting curve of indoor and outdoor monitoring concentration andthe exponential fitting curve of the indoor concentration over time，a theoretical study of Xi’anCity, an ordinary office room indoor particulate emission sources and indoor particleconcentration variation characteristics were analysised; finally, the control strategy of indoorparticulate pollution were proposed. Through the above analysis can get the followingconclusions:(1) when indoor concentration C0>C∞, indoor particle concentration emerge thetrend of "low during the day and high at night"; when C0<C∞, indoor particle concentrationemerge the trend of "high during the day and low at night"; when C0=C∞, air conditioningsystem of indoor particle concentration values remain in the initial concentration of C0.(2)For natural ventilation without indoor dust source, the ratio of I/O increased with ventilationrate increasing, meanwhile the I/O ratio of PM10and PM2.5were less than1, the results showthat the indoor particle pollution sources mainly from the outdoor; due to the interior deposition rate of PM2.5was less than PM10, the I/O ratio of PM2.5greater than PM10. Whenthe number of air exchange rate increased from1to6h-1, the I/O ratio of PM10and PM2.5wereincreased from0.50,0.71to0.86,0.94respectively, increased by72%,32.4%. The influenceon fine particles’ I/O ratio was smaller than PM10as the increasing of air exchange rate, whencontinue to increase the number, the I/O ratio tended to be gentle.(3) combining with massbalance equation, the linear fitting curve of indoor and outdoor monitoring concentration andthe exponential curve fitting of indoor concentration versus time, a theoretical study of Xi’anCity ordinary office’s indoor particulate emission sources were analysised; the results showthat the indoor PM10average dust was7.93~12.48mg/h, the average dust indoor PM2.5was2.89~4.08mg/h. Through the comparison of fitting exponential curve with indoorconcentration, verified the accuracy of the calculation results.(4) Numerical calculation showthat ventilation dilution of indoor particle was limited, should combined with the air filter tocontrol the indoor particle pollution; air filter conditioning system have a minimumventilation rate from the control of indoor particulate pollution angle. Therefore, in the designof air conditioning system, ventilation frequency calculation can not only from the processingof heat and moisture load to determine the requirements, it should also from the angle ofimproving the indoor air quality and controlling the concentration of indoor particulate tocheck the air exchange rate. |
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