Effect Of Outdoor Inhalable Particles On Indoor Air Quality And Its Control

Associations have been observed between outdoor particles and mortality,respiratory and cardiovascular diseases and cancer. Especially in China, due to thedevelopment of the society and economy, outdoor particulate air pollution is veryserious. Meantime, people spend most of their time indoors. Therefore, it is importantto explore the impact of outdoor particles on indoor air quality and its control.First of all, the relationship between indoor and outdoor particles was reviewed.The experimental data as well as the experimental and modeling methods of the threemain parameters, indoor/outdoor particle concentration ratio, infiltration factor andpenetration factor, were reviewed in order to give a general sense of the entry ofoutdoor particles to indoor environments. Then, starting with the health effect, theassociation between indoor particles of outdoor origin and mortality was assessed.The results for83U.S. cities and7U.S. regions show that significant positiveassociation between outdoor-to-indoor transport of particles and mortality. Afterdemonstating the importance of this topic, the calculation for the entry of outdoorparticles to indoor environments was studied in order to determine the control ‘target’.Four different calculation models for the key parameter, penetration factor, werecomparied with each other in order to identify the best model with high accuracy andeasy use. Since the existing models for penetration factor were based on ideal orexperimental conditions, a method for estimating the penetration factor in realbuildings was proposed and valided by field measurements. At last, the controlstrategies for preventing the entry of outdoor particles were studied. The experimentaland calculation results show that in some cases positive pressure control method cannot work due to the effect of two-way airflow owing to temperature difference.Furthernore, outdoor air velocity and effective crack area coefficient are amoung themost important influencing factors of positive pressure control method. In addition,positive control method was comparied with indoor filtration method.