Abstract---Background: Indoor air quality is "of interest" to healthcare providers because of its importance in maintaining the health of internal and external customers, as the air can transmit various microbes, including pathogenic ones. Objectives: This study aimed to investigate Indoor air quality in private and governmental healthcare institutions in Nablus -Palestine. As well as compare the results before and during the COVID-19 Pandemic; by finding the effect of adhering to the public health and safety guidelines imposed by the Ministry of Health. Methods: Samples were collected by passive approach from two different hospitals at five departments where most activities and tasks are performed inside, Besides two –various sites outside the hospital, in an average of three hours. The positive colonies were identified by using several biochemical tests. Then, the Total Microbial Load (CFU/plate) was calculated for each plate. Results: The predominant Gram-positive bacteria in Rafidia
6551Governmental Surgical Hospital was S. aureus,present in daycare and emergency departments and Aer. hydrophila gr.1 among Gram-negative bacteria found in the surgical department. While in An-Najah National University Hospital (NNUH), the predominant Gram-positive bacteria were S. epidermidis and S. saprophyticus, present in departments of surgery and laboratories, respectively. At the same time, Pseudomonas luteola is among Gram-negative bacteria found in daycare departments. Also, the level of airborne microbial pollutants in Rafidia Governmental Surgical Hospital appeared in greater proportions than in NNUH, as it reached in Rafidia Governmental Surgical Hospital (12430.1188 CFU/m3), while in NNUH (11779.3501 CFU/m3). Besides, it was also found that the levels of microbial airborne in confined and crowded areas are much higher than in sparsely populated areas. Furthermore, the percentage increased in rooms with high temperatures and humidity. Finally, infection levels during the Corona pandemic are lower than in the pre-pandemic period. Conclusions: Environmental factors like crowding, temperature, and humidity affect airborne microbes' levels. As a result, it concluded that Rafidia Governmental Surgical Hospital is more polluted with microbial airborne; another reason could be due to the smallness ofits facilities compared to NNUH. This study note the evidence and results that confirm our conclusion. As in comparing with previous studies, microbial pollution levels during the Corona pandemic were lower than in the pre-pandemic period, which means a commitment by the hospital's staff and patients to the public health and safety guidelines imposed by MOH, including the necessary sterilizations, wearing a mask and maintaining social distancing.