Microbial air contamination with air borne bacteria in the outdoor environment at Janakpurdham, Nepal

Abstract

Background and Objectives: Bacteria can cause allergic asthma and seasonal allergies, diseases which are increasingly prevalent in developing nations. Allergic asthma is currently affecting millions of people in Nepal. Therefore, the objective of this study was designed to measure the bacterial load in outdoor air.
 Materials and Methods: Airborne outdoor bacteria were assessed during the spring season using conventional methods to investigate the enumeration of airborne microorganisms. This was determined by sampling air using the ‘settle plate technique’. The air samples were collected during the spring season (February-March) from 10 different areas of Janakpur. Counts of airborne bacteria were measured as CFUs collected by gravity onto Nutrients Agar plates. Samples were taken periodically over a period of 2 months of February and March 2017.
 Results: A total of 7,404 bacterial colonies were counted on 30 Petri plates that were exposed for 1 hour. The maximum number of colonies of bacteria was 412. Similarly, the least number of bacterial colonies was 32. Higher numbers of CFUs were found in the petri plates which were exposed for 1 hour in comparison to the petri plates which were exposed for 30 minutes. According to the measurement, 36.6% of total CFUs of bacteria were collected during morning hours, 28.4% during day time and 35% during evening hours. Also, the highest numbers of colonies of bacteria were found in the petri plates that were exposed in ward number 7 and the least number of bacterial colonies were obtained in ward number 9.
 Conclusion: The bacteriological quality of air in janakpur was very poor. Very high microbial load was found in the outdoor air in Janakpur. The microbial count was found higher in morning than the noon and evening.