Assessment of Bacterial Aerosol in a Preschool, Primary School and High School in Poland

Ewa Brągoszewska,Yitages Desta,Katarzyna Lizończyk,Józef Pastuszka,Anna Mainka

doi:10.3390/atmos9030087

Abstract

The issue of healthy educational buildings is a global concern because children are particularly at risk of lung damage and infection caused by poor indoor air quality (IAQ). This article presents the results of a preliminary study of the concentration and size distribution of bacterial aerosol in three educational buildings: a preschool, primary school, and high school. Sampling was undertaken in the classrooms with an Andersen six-stage impactor (with aerodynamic cut-off diameters of 7.0, 4.7, 3.3, 2.1, 1.1 and 0.65 μm) during spring 2016 and 2017, as well as the outside of the buildings. After incubation, bioaerosol particles captured on nutrient media on Petri dishes were quantitatively evaluated and qualitatively identified. The highest average concentration of bacterial aerosol was inside the primary school building (2205 CFU/m3), whereas the lowest average concentration of indoor culturable bacteria was observed in the high school building (391 CFU/m3). Using the obtained data, the exposure dose (ED) of the bacterial aerosol was estimated for children attending each educational level. The most frequently occurring species in the sampled bacterial aerosol were Gram-positive cocci in the indoor environment and Gram-positive rod-forming endospores in the outdoor environment.

Highlights

Indoor air quality (IAQ) is becoming an increasingly important issue for occupational and public health because people spend more than 90% of the day in indoor environments [1,2,3,4,5]
According to the Central Statistical Office, in 2015 [9] there were more than 6.3 million children being educated in over 52,000 Polish preschools and schools, monitoring the air quality in educational buildings is a critical area of research
Inadequate hand washing, direct contact during the classes, as well as being in constant motion favor the spread of bacterial infections, which increases the risk of exposure to harmful microorganisms [71]. This is the first study in Poland that has investigated the levels and size distribution of airborne bacteria in indoor air in different educational buildings

Summary

Introduction

Indoor air quality (IAQ) is becoming an increasingly important issue for occupational and public health because people spend more than 90% of the day in indoor environments [1,2,3,4,5]. One group of particular concern are children. They are more vulnerable to environmental pollutants compared to adults since they breathe more air relative to their body weight and they have a lower ability to deal with the toxic chemicals due to their undeveloped airways [6,7,8]. Aerosol particles are one of the pollutants that can cause a decrease of IAQ in different educational buildings. These buildings offer unique chemical environments, not encountered in the natural world, that may enhance the development of bioaerosols [11]. Bioaerosols are a large category of airborne particles, comprising bacteria, fungi, Atmosphere 2018, 9, 87; doi:10.3390/atmos9030087 www.mdpi.com/journal/atmosphere

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Conclusion