Students in Cape Town spend almost 60 percent of their day in poorly ventilated rooms, and are at risk of transmission, say scientists studying in role of room ventilation in tuberculosis transmission. The results are published May 7, 2014, in the open access journal PLOS ONE by Eugene Richardson from Stanford University School of Medicine and colleagues. The researchers propose an increase in low-cost, WHO-compliant natural ventilation to facilitate healthy indoor environments and reduce risks.

Despite biomedical improvements to treat tuberculosis (TB), the incidence in South Africa continues to increase. TB spreads through the air, and children attending school may be particularly vulnerable to the disease because they are required to spend large amounts of time indoors in classrooms. Over one school year in a high school in Cape Town, South Africa, scientists assessed the role of schools and 'air hygiene' in TB spread or prevention by monitoring CO₂ in classrooms—using sensors carried around by students.

In the study, the authors first calculated 1000ppm as the indoor CO₂ concentration threshold above which indicates a high amount of rebreathed air and increased risk of TB transmission. This level falls in line with regulations in other industrialized nations.