Study On The Pollution Investigation And Growth Of Fungi In Accumulated Dust In Air-Conditioning Ducts

As one of the important pollutants in the indoor environment,fungi are critical factors that cause a variety of related diseases(asthma,allergies,and respiratory diseases,etc.),which seriously threaten the safety of the indoor environment.The HVAC system is one of the important sources of indoor fungal contamination,thus affecting indoor air quality closely.Therefore,this paper mainly studies three aspects of pollution assessment,growth experiments,and growth prediction,on the problem of fungal pollution in HVAC systems that have received more and more attention.In this study,two independent central air-conditioning systems in a large auditorium and a VIP room were chosen as research objects in Baoding City.The surfaces of the filter screen,the air cooler and the air supply duct of two air handling units were tested in the field.The fungal diversity in accumulated dust in different test sites was determined,the dominant species and their content in each site were obtained,and the pollution levels and cleaning effect of HVAC systems were evaluated,as well;The air-conditioning duct simulation test bench with controllable airflow parameters was set up,and the experiment on growth characteristic of the fungi in accumulated dust was carried out.The impact degree of temperature,relative humidity,duct material,and growth duration on the fungal growth was studied.The influence of the coupling effect of different environmental factors on fungal growth was explored and the optimal conditions to inhibit fungal growth under the operating conditions of HVAC systems were determined,as well;Based on the above results,Logistic,Gompertz and Square-root equation were respectively adopted to fit primary and secondary growth prediction models for the fungi in accumulated dust under different environmental conditions.The imitative effect of different models with the variation of the experimental environment was explored and the feasibility and accuracy were verified.Finally,the optimal growth prediction model of the fungi in accumulated dust under the operating conditions of HVAC systems was determined.Utilizing field test,experimental and model analysis,this paper studies the diversity of species and the growth characteristics of fungi in accumulated dust in air-conditioning ducts.Optimal growth prediction models were also established to accurately assess the degree of fungal contamination in accumulated dust in HVAC systems,and achieve realtime prediction of fungal contamination processes in air-conditioning ducts.This study can contribute to guide the cleaning and disinfection of HVAC systems and provide a scientific basis for improving the increasingly serious fungal pollution problems in public places.