Evaluation of indoor bacterial load and its association with respiratory symptoms among children in Kuantan early childhood centres

Background: Indoor air quality (IAQ) plays a crucial role in ensuring a healthy and comfortable environment, particularly in early childhood education centers (ECEs). Children are especially vulnerable to poor IAQ due to their developing immune and respiratory systems. This study investigated the indoor bacterial load and the associated respiratory symptoms among children in selected ECEs in Kuantan, Pahang. Methods: A cross-sectional study was conducted in two urban ECEs from March to April 2025 to assess indoor bacterial counts and physical parameters (temperature and relative humidity), which were measured with the Surface Air System SAS IAQ 100 and the Testo Air Meter 440, respectively. Potential respiratory symptoms (cough, wheezing, phlegm, and breathlessness) were assessed in 30 children aged from 3 to 6 years using a parentadministered questionnaire adopted from the American Thoracic Society. Results: Both ECEs A and B recorded total bacterial counts exceeding the Industry Code of Practice (ICOP) limit, with concentrations of 617.22 CFU/m3 and 647.22 CFU/m3, respectively. The recorded temperatures (27.41℃ and 27.96℃) also surpassed the ICOP comfort range. Among the children, cough was the most commonly reported symptom (23.3%), followed by wheezing (16.7%), and phlegm (10.0%). No case of breathlessness symptom was reported in children. Statistical analysis indicated no significant association between the indoor bacterial load and the respiratory symptoms observed. The study was limited by the small sample size and the short monitoring duration, which may not fully represent variations in bacterial levels across different times or seasons. Additionally, the high bacterial counts observed might have been influenced by occupant density, cleaning practices, and ventilation patterns, which were not controlled in this study. However, the present findings provide valuable baseline data on indoor bacterial concentrations, where the local evidence remains limited. Conclusion: Overall, the findings indicate early signs that IAQ in ECEs may fall below recommended standards, underscoring the need for better cleanliness and ventilation practices to improve indoor environments and protect children’s health. These results also provide useful direction for future research, monitoring efforts, and targeted interventions.