Assessment of Ventilation System, Comfort Level and Microbial Air Quality of Academic and Hospital Building

Abstract

This study aimed at performing the following objectives (i) investigating and comparing indoor air quality (IAQ) and thermal comfort in classrooms of four departments of NUST having different types of heating ventilation and air conditioning (HVAC) system; (ii) seasonal(winter and spring) assessment of airborne microbial levels in eight hospital sites of a publically managed hospital of Islamabad; (iii) airborne microbial levels assessment in three cafeterias (A, B and C), with different HVAC system. On-site continuous measurements of indoor levels of carbon dioxide (CO2), temperature (T) and relative humidity (RH) were recorded from fifteen classrooms and two hospital locations at an interval of 1 minute for both weekdays, including occupational and non-occupational hours, as well as weekends. However, microbial samples from six hospital locations (twice a week covering one month for each season) and three cafeterias (each having two indoor locations and one outdoor) were collected during the peak hours. Simultaneous outdoor temperature and relative humidity measurements were also monitored during the study and used in the analysis. Results of mean hourly CO2values and thermal comfort parameters of selected classroom and hospital site showed significant difference over the weekday and also among different buildings. Exceedance in levels of CO2 from ASHRAE standards was found to be more in buildings with non-centralized systems as compared to centralized systems. Moreover, thermal comfort parameters were influenced by outdoor climatic conditions and buildings orientation. Bacterial concentration levels of hospital sites didn’t exhibit any significant seasonal variation however fungal concentrations were different. Highest bacterial level in hospital and cafeterias were found in OPD and CafeBSC, while lowest in OT1 and in CafeCC2. Moreover, highest fungal level was found in GMW and CafeASC while lowest in OT2 and CafeCC2. Identified bacterial strains from both monitored locations belonged to genera staphylococcus, micrococcus, kocuria, aerococcus, kytococcus, bacillus and pseudomonas. However, the most dominant fungal genera include cladosporium, aspergillus, penicillium, alterneria, geotrichium, fuserium and ulocladium.