Spatio-temporal variations of indoor air quality in a university library

ABSTRACT

The present study aims to assess the air quality status in the central library of Indian Institute of Technology Roorkee, India. Pollutants concentrations (i.e. PM₁₀, PM_2.5, PM₁ and TVOC) and comfort parameters i.e. CO₂, temperature and relative humidity were monitored across all floors of the library. Air quality was found to vary significantly (P < 0.05) among the different floors of the library. The average concentration of PM₁₀, PM_2.5 and PM₁ was found to be highest at the first floor. On the other hand, the highest concentration of TVOC (51.7 ± 30 ppb) and CO₂ (838.4 ± 99 ppm) was observed at the ground floor. Pollutant concentration was higher in the morning hours. The indoor pollutants were found positively correlated with each other except relative humidity. Indoor to outdoor ratio for PM₁, TVOC and CO₂ was found to be greater than 1, which indicate a substantial contribution from indoor sources. Exceedance of WHO guidelines was observed for the daily average PM_2.5 concentration.

Abbreviation: IAQ: indoor air quality; ASHRAE: American Society of Heating, Refrigerating, and Air-Conditioning Engineers; WHO: World Health Organization; PM: particulate matter; VOC: volatile organic carbon; CO₂: carbon dioxide; TVOC: Total volatile organic compound; RH: relative humidity; HVAC: heating ventilation and air-conditioning; PID: Photo Ionization Detector; PTFE: Polytetrafluoroethylene; NDIR: Non-dispersive infra-red.

KEYWORDS:

• Indoor environment
• indoor-outdoor ratio
• mechanically ventilated
• air pollution
• India

Acknowledgments

The Max Planck Society, Munich, and the Max Planck Institute for Chemistry, Mainz, Germany, have supported this study through the Max Planck Partner Group for Megacities and Global Change established at Indian Institute of Technology Roorkee, India. Special thanks to Government of India, Ministry of Human Resource Development (MHRD) for support all form of assistance. We also thank to Dr. C. Jayakumar (librarian) and Sh. Sompal Singh (Deputy librarian) for providing necessary information and support for conducting the study.

Disclosure statement

Authors have no conflicts of interest to disclose.

Highlights

• IAQ varied significantly within different floors of the library.

• Positive correlation was found among PM with TVOC, CO₂ and temperature.

• Indoor to outdoor ratio was greater than 1 for PM₁, TVOC and CO₂.

• Indoor PM_2.5 concentration exceeded the recommended WHO guidelines.

Additional information

Funding

This work was supported by the Government of India, Ministry of Human Resource Development (MHRD);Max Planck Partner Group for Megacities and Global Change established at Indian Institute of Technology Roorkee, India.