Microbiological contamination of indoor and outdoor environments in a desert climate

Abstract

Microbiological air contamination in the desert environment is becoming an essential subject for the health of office building occupants and public health. In this study, the concentrations and compositions of airborne microorganisms (bacteria and fungi) were assessed in indoor and outdoor environments using a multistory building complex in Kuwait as a case study. Airborne microorganism samples were collected from 12 sites within the building complex containing nineteen stories over four seasons. Culturable airborne bacteria and fungi were impacted on selected media to determine their concentrations and compositions with a Biolog Omnilog GEN III system and Biolog MicroStation. The indoor mean airborne bacterial count concentrations ranged from 35 to 18,463 CFU/m 3 , concentrations that are higher than 2,000 CFU/m 3 , demonstrating high–very high contamination levels in all seasons. Fungal contamination was high in winter and summer, with detected concentrations > 2,000 CFU/m 3 . Indoor-to-outdoor (I/O) ratios showed that airborne microbial contamination inside building floors originated from indoor air contamination. All the building floors showed bacterial and fungal concentrations ranging from less than 2,000 to more than 2,000 CFU/m 3 , indicative of a high to very high air contamination level. Statistical analysis showed no correlation between bacterial and fungal concentrations, demonstrating that they originated from unrelated sources. In the indoor building air, the most prevalent bacterial isolate was Bacillus pseudomycoides/cereus , whereas the most dominant fungal isolate was Aspergillus spp. The low count for indoor air bacterial species suggested no particular health risk for the occupants. In contrast, the high count of indoor air fungal species in the winter samples and the presence of potentially allergenic genera detected may suggest possible health risks for the occupants. The results obtained are the basis for the recommendation that the maintenance activities of the HVAC system and the periodical cleaning operation program be revised and preplanned as protective measures.

Risk of Fungal Growth in Nearly Zero-Energy Buildings (nZEB)

“…Moreover, the ventilation rate is more significant for the mold index than the cooling setpoint temperature. On the other hand, Almatawah et al [55] evaluated the concentration of airborne microbes (bacteria and fungi) in the external and internal environment for a case study in Kuwait's hot and arid desert climate. The concentration of fungi was very high in summer and winter, demonstrating a very high level of contamination.…”

Mechanisms, Techniques and Devises of Airborne Virus Detection: A Review

“…The outdoor environment is multi-factorial and complex, and outdoor aerosol monitoring necessitates collaboration with related fields such as environmental monitoring, air pollution control and weather forecasting, as well as the establishment of large monitoring stations for multi-indicator environmental aerosol monitoring and prediction [144]. The CDs mentioned in this review are for monitoring, detection, and early warning of viruses in the indoor environment, and their proper application is critical for developing solutions for fighting airborne diseases (Table 1/2) [145]. Here, we classify indoor environmental monitoring equipment into two groups: high-flow environment aerosol monitoring devices and portable environmental sensor.…”

Mechanisms, Techniques and Devices of Airborne Virus Detection: A Review

“…The outdoor environment is multi-factorial and complex, and outdoor aerosol monitoring necessitates collaboration with related fields such as environmental monitoring, air pollution control and weather forecasting, as well as the establishment of large monitoring stations for multi-indicator environmental aerosol monitoring and prediction [ 169 ]. The CDs mentioned in this review are for monitoring, detection and early warning of viruses in the indoor environment, and their proper application is critical for developing solutions for fighting airborne diseases ( Table 1 and Table 2 ) [ 170 ]. Here, we classify indoor environmental monitoring equipment into two groups: high-flow environment aerosol monitoring devices and portable environmental sensor.…”