Natural ventilation in hospital wards of semi-arid climates: a case for acceptable indoor air quality and patients’ health

Owing to the growing concern about indoor air quality (IAQ) globally in hospitals, especially after the recent outbreak of diseases like severe acute respiratory syndrome (SARS), Swine Flu (H1N1) and other airborne infections such as Tuberculosis, the quest for energy efficient ventilation system is growing. To provide acceptable indoor air quality that is capable of removing indoor air contaminants in hospital wards, sustainable ventilation strategy is required.  Therefore, this paper tends to exploit the possibilities of using natural ventilation strategies in providing acceptable indoor air quality in hospital wards of semi-arid climates. The study established that, Mosquito insects, Harmattan dust, and high temperatures are the three major factors militating against the achievement of natural ventilation in semi-arid climates of Nigeria.  Mosquito insects remain the only source of Malaria parasites that kills thousands of people in the tropics, while the inhalation of Harmattan dust causes cardiovascular and respiratory diseases.     
To achieve the objectives of this study, a comprehensive literature review, full-scale measurement and field survey have been conducted. The results obtained from the field measurement shows that none of the hospitals measured achieved the required ventilation rates of 6 ACH as enshrined by AHSREA. Moreover, the survey results for the five hospitals studied shows that more than 80% and 90% of the respondents have admitted the presence of Harmattan dust and mosquitoes respectively in the hospital multi-bed wards. Therefore, the design of sustainable natural ventilation that can remove indoor contaminants while excluding outdoor pollutants in the hospital wards of semi-arid climates without compromising occupants comfort is essential.