Assessment of the Indoor Environmental Conditions of Air in Libraries
Authors: Barros Aurea Lucia de Sousa , Mota Alexya Gonçalves , Dias Léo Ruben Lopes , Amaral Sielys dos Santos , Miranda Rita de Cássia Mendonça de , Villis Paulo Cesar Mendes 
Published: September 2024

Introduction: Libraries are environments with high circulation and close contact among people, impacting human health and, therefore, must maintain good indoor air quality. This article aims to evaluate the environmental conditions of the air in air-conditioned libraries in São Luís (MA). Collections were made in 3 (three) large and easily accessible libraries, quantifying microorganisms (fungi and bacteria) and parameters such as temperature (T, °C), relative humidity (RH, %), carbon dioxide (CO2, ppm), and noise [dB(A)]. The data were analyzed and compared with specific legislation, according to the Resolution of the National Health Surveillance Agency (ANVISA). Sampling involved 10 (ten) equidistant points in the libraries, in four periods over 12 months. To quantify microorganisms, the deposition technique was used, where air particles settle on Petri dishes with selective medium for fungi and bacteria. The plates were exposed for 30 minutes and incubated at 27 ºC for 48 to 72 hours. All points were evaluated in triplicate, using Sabouraud Agar, Mueller Hinton Agar, and MacConkey Agar. After collection, colonies were quantified and purified in specific media using the streak plate method. The plates were incubated at 30 ºC for up to 48 hours for identification and association with ambient temperature and humidity. The results confirm the presence of microorganisms in these environments; however, in none of the analyzed points did the quantitative exceed the values allowed by current legislation. The research provides library managers with mitigating measures to preserve the collections and protect the health of occupants.
 
Objective: The objective of this study is to investigate air quality, aiming to evaluate indoor air quality concerning microbiological parameters and comfort parameters (temperature, relative humidity, CO2, and noise level) in indoor environments.
 
Theoretical Framework: This section presents the main concepts and theories that underpin the research. The theory of Sick Building Syndrome (SBS) described by the World Health Organization (WHO), which associates poor indoor air quality with various health problems, the model of monitoring physical-chemical and microbiological parameters in indoor environments, which includes the measurement of carbon dioxide (CO2), humidity, temperature, and noise, and the approach of correlating environmental conditions with the prevalence of microorganisms such as Aspergillus and Penicillium, providing a solid basis for understanding the context of the investigation.
 
Method: The methodology adopted for this research comprises a descriptive observational study with a quantitative approach. The participants were libraries A, B, and C in the municipality of São Luís (MA). The instruments used included Petri dishes with different selective culture media for fungi and bacteria (Sabouraud Agar, Mueller Hinton Agar, and MacConkey Agar). The procedures involved exposing the plates to the indoor air of the libraries for 30 minutes, followed by incubation at 27 ºC for 48 to 72 hours. Data collection was carried out through sampling at ten equidistant points in the libraries in four distinct periods over 12 months.
 
Results and Discussion: The results obtained revealed that the fungal count did not exceed the maximum value established by current legislation of 750 CFU/m³, and the main isolated genera were Candida spp., Aspergillus sp., and Penicillium sp. A significant correlation was observed between relative humidity and the presence of microorganisms. In the discussion section, these results are contextualized in light of the theoretical framework, highlighting the implications for health in library environments and the need for control measures. Possible discrepancies and limitations of the study are also considered in this section.
 
Research Implications: The practical and theoretical implications of this research are discussed, providing insights into how the results can be applied or influence practices in the field of air quality control in libraries. These implications may include adopting preventive measures to keep microorganism levels within the limits allowed by legislation, implementing adequate ventilation systems, continuous monitoring of humidity and temperature, and guiding public policies aimed at occupational health and preservation of bibliographic collections.
 
Originality/Value: This study contributes to the literature by investigating the microbiological quality of air in libraries, using a quantitative and innovative approach that integrates physical-chemical and microbiological parameters. The originality of the research lies in the combination of different collection and analysis methods in a specific and underexplored environment. The relevance and value of this research are evidenced by its implications for public health and the preservation of bibliographic collections, providing essential data for the implementation of environmental control policies and practices in libraries.