Healthy Buildings 2017 Europe July 2-5, 2017, Lublin, Poland

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1 Healthy Buildings 2017 Europe July 2-5, 2017, Lublin, Poland Paper ID: 0025 ISBN: Assessment of Bioaerosol and Microbial Volatile Organic Compounds in a Library environment Himanshu Lal 1, Bipasha Ghosh 1*, Arun Srivastava 1 1 School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India. * Corresponding bipashaju@gmail.com SUMMARY The present study was carried out to depict the seasonal variation in both MVOCs and bioaerosol concentration as well as to identify their sources in the indoor environment of a library. Anderson six stage viable sampler was used to collect bioaerosol while ORBOTM 90 Carboxen 564 for MVOCs and analysed by GC-FID. Surface dusts were collected by sterilised buds. Unlike bacteria, fungal bioaerosol is found to affect the secondary bronchi in human lungs mostly. Both the bioaerosol fractions were higher in post monsoon season while MVOCs were found maximally in the monsoon season. I/O ratio depicts greater source in indoor in monsoon season for which rain washout in outdoor could be the reason. Aspergillus, Cladosporium and Penicillium found both in air and dust indicates dust as one of the sources. Increase in mechanical and natural ventilation along with regular check on accumulated dust could prevent student s exposure to such pollutants. KEYWORDS Indoor air, Bacteria, Fungi, 1-hexene, 1-pentanol 1. INTRODUCTION Studies report human being spend most of their time (approximately 85%) in indoor environments such as schools, homes, etc., (Jenkins et al., 1992) than outdoor supporting the fact that in comparison to outdoor pollutants people inhale indoor air pollutants one thousand times more (ICMR, 2001). This also justifies the close association between different respiratory illness including asthma with indoor air pollutants (Delfino, 2002) such as particulate matter, various gaseous pollutants along with bioaerosol and metabolites of microbes like mycotoxins, microbial volatile organic compounds (WHO, 2010; Ghosh et al, 2015). Majority of bioaerosols are respirable fractions of airborne particles consisting of microbes or materials originating from them, like spores, cellular fragments etc. (Stetzenbach et. al., 2004). Microbial volatile organic compounds (MVOCs) are low molecular weight compounds released by both primary and secondary metabolic pathways of microbes (Korpi et al., 2009) and are suggested as indicators of the hidden indoor moulds (Elke et al., 1999). Till date no study has been carried out depicting the diel and seasonal variation in MVOCs concentration. Keeping in mind, the importance of the role of MVOC s in the sensitive

2 environments the present study was carried out to depict the seasonal variation in both MVOCs and bioaerosol concentration as well as to identify their sources. 2. MATERIALS/METHODS Study area and sampling site Study area Delhi (the National Capital Territory of India), is a metropolitan region of India characterized as humid subtropical climate. Sampling was carried out in 4 different sections (reading hall, 3rd floor, 4th floor and basement book section) of 43 year old nine storeys library in a university in Delhi that is surrounded by dense and/or scrubby vegetation. Sampling and estimation of bioaerosol and MVOCs and fungal isolation from dust samples Bioaerosol sampling (both fungus and bacteria) using Anderson six stage viable cascade impactor as well as estimation was carried according to the process described by Maharia and Srivastava (2015). Growth media such as Potato Dextrose Agar (PDA) for fungi and Tryptone Soya Agar (TSA) for bacteria were used in petridishes as the target. Samplings were carried out thrice every month in monsoon (July-September) and post monsoon (October-December). Active sampling of 1-pentanol, 1-octen-3-ol, 1-hexene and cyclohexanone were carried with the help of a pump at flow rate of 200 ml/min on activated charcoal tubes ORBO 90 Carboxen 564. The sorbent were extracted with 1 ml of carbon disulfide with help of vortex vibrator. 1 μl of each extract were analysed in GC FID (Elke et al., 1999). Fungal strains were extracted by stirring the dust samples (collected by sterile cotton buds from books, wooden shelves etc.,) in 50 ml physiological sterile solution (i.e., 0.85 % NaCl, 0.5 % Tween 80) for 1hr, followed by inoculation on the PDA media with 0.5 ml of this solution. For identification till species level pure cultures were sent to the Plant Pathology Department, IARI, New Delhi. Data Analysis Statistical analysis such as Regression between bioaerosol concentration and environmental parameters (temperature and relative humidity) was carried out using Microsoft Excel Statistical analysis of MVOCs could not be carried out due to insufficient data. 3. RESULTS Size segregated distribution and seasonal variation of bioaerosol in different sections The concentration of fungal bioaerosol found in different stages at each site seems to follow a typical pattern in both the season (figure 1A, 1B) with an increasing trend from stage 1 to 4 with a further decrease from stage 4 to 6. Thus highest concentration of fungus is found at stage 4 (diameter ranging from 2.1 to 3.3 µm). Unlike fungi, bacterial concentration does not follow any typical pattern of size distribution (figure 1C, 1D).

3 A B C D Figure 1: Size segregated distribution of fungus (A & B) and bacteria (C & D) in monsoon (A & C) and post monsoon (B & D) season. As seen in figure 2 fungal and bacterial bioaerosol were found maximally in post monsoon season ( CFUm-3 and CFUm-3 respectively) than monsoon season. An indoor/outdoor (I/O) ratio of bioaerosol concentration was also calculated where it was found to be 1 or >1 for both the fractions majorly in the monsoon season. Figure 2: Seasonal distribution of fungal (A) and bacterial (B) bioaerosol Identification, quantification and seasonal variation of MVOCs Among the 4 MVOCs, 1-hexene, 1-pentanol followed by 1-octen-3-ol were detected in almost all the sections of library in monsoon season with 1-hexene having the highest concentration of 7.09µgm-3 (table 1).

4 Table 1: Microbial volatile organic compounds concentration in µgm -3 in Monsoon and Postmonsoon seasons Seasons MVOCs Mea n SD Minimu m Maximum Temperature (ºC) Relative Humidity (%) Monsoo n Postmonsoo n 1-Octen-3-ol Hexene Cylohexanone Pentanol Octen-3-ol Hexene Cyclohexanon e Pentanol Fungal species identified in bioaerosol and surface dust Aspergillus, Alternaria, Curvuleria, Cladosporium, Penicillium and Drechslera were the six identified fungal bioaerosol out of which Aspergillus, Cladosporium and Penicillium were maximally found in various sections of library. Four fungal species namely Aspergillus niger, Curvuleria lunata, Cladosporium cladosporioides and Penicillium sp., were indentified in surface dust samples. Statistical analysis No significant regression of temperature and relative humidity on both fungal (R 2 = 0.318, 0.027) and bacterial (R 2 = 0.129; 0.078) concentration respectively. 4. DISCUSSION Size segregated study of fungal bioaerosol in both the season report higher concentration in stage 4 (in synonym to secondary bronchi of human lungs) depicts that hyphal fragment and spores of immunotoxic and allergic fungi like Aspergillus, Alternaria, Dreschlera are prone to affect the secondary bronchi in human lungs when inhaled. Unlike fungi, bacterial bioaerosol did not follow any pattern. Random distribution in different stages indicates higher probability of bacteria affecting majority of the parts of human respiratory system (nasal passage, trachea, primary bronchi to alveoli) in different season on inhalation. Seasonally both fungal and bacterial bioaerosol were found maximally in post monsoon season. According to ACGIH (1995) and CEC (1994) reports fungal concentration ranges between intermediate to very high level. Although, the temperature range in both the seasons were optimum for microbial growth over various substratum such as accumulated surface dusts, wooden racks, old books, periodicals etc., yet higher range of relative humidity (ranging up to 79%) observed in monsoon season could be one of the major reasons of restricted aerosolisation of microbes in monsoon than in post post-monsoon in accordance to studies carried out by De Goffao et al. (2009) and Li et al. (2011). Hence high relative humidity was found to correlate with low bioaerosol concentration. Along with inhibited aerosolization of microbes due to high relative humidity, rain wash out can be attributed as another reason for lower outdoor bioaerosol concentration in comparison to indoor (I/O ratio 1 or >1) in monsoon season. Thus in monsoon season indoor sources such as cellulosic matter in the form of periodicals, books, etc.; surface dust containing Aspergillus niger, Curvuleria lunata, Cladosporium cladosporioides and Penicillium sp., and occupancy (especially for bacteria) were greater than outdoor infiltration (Ghosh et al., 2013). Presence of Aspergillus, Alternaria and Curvuleria in

5 abundance represents an allergic and contaminated environment for the students and workers in the library. Among the four MVOCs, 1-pentanol, 1-hexene and 1-octen-3-ol were maximally found while in the indoor air samples revealing presence of proper sources for these MVOC productions. Optimum temperature and RH ranges of C and % found in monsoon season could be attributed to be the reason of microbial proliferation in dust and building materials present in indoor environments, which itself acts as a source of MVOCs. Presence of Aspergillus sp., in dust can be correlated to presence of 1-octen-3-ol (Elke et al., 1999). Apart from fungus, bacterial community thriving upon accumulated dusts, building materials, etc., can also be the source of several MVOCs such as cyclohexanone, 1-pentanol, etc., (Matysik et al., 2009). Presence of MVOCs in air not only indicates hidden biocontaminants but also excess moisture damage of the building (Pasanen et al., 1998) with or without odour complaint. No other VOCs were studied apart from the mentioned ones. 5. CONCLUSIONS From this study it may be concluded that although optimal environmental parameters along with presence of moisture are essentially required for growth of microbes on suitable substrates such as cellulosic materials, dusts, building materials etc with eventual release of MVOCs, however, for fungal bioaerosol along with proper substratum mechanical movements of books from racks (students) and dusting and cleaning activity by workers is necessary for them to become airborne. In case of bacterial bioaerosol which is maximally found in the reading room, can be directly and indirectly associated with human occupancy. Being a 43 year old building mostly occupied by students, this study suggests maintenance of the building walls with precautionary care to keep them moisture free, increase both mechanical and natural ventilation of the building along with intermittent mechanical cleaning of books and racks so as to prevent accumulation of dusts. 6. ACKNOWLEDGEMENT The team conveys special thanks to the management of the library for providing opportunity to collect air and dust samples and team of scientists in Division of Mycology and Plant Pathology, Indian Agricultural Research Institute, New Delhi for authentic identification of fungal species. The Senior Research Fellowship provided by the Council for Scientific and Industrial Research (CSIR), New Delhi is gratefully acknowledged as well. 7. REFERENCES American Conference of Governmental Industrial Hygienists Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices; ACGIH: Cincinnati, Ohio, USA, De Goffau, M. C., Yang, X., Van Dijl, J. M., and Harmsen, H. J Bacterial pleomorphism and competition in a relative humidity gradient. Environmental microbiology, 11(4), Delfino R. J Epidemiologic evidence for asthma and exposure to air toxics: linkages between occupational, indoor, and community air pollution research. Environmental Health Perspectives, 110(Suppl 4), 573. Elke K, Begerow J, Oppermann H, Kråmer U, Jermann E, and Dunemann L Determination of selected microbial volatile organic compounds by diffusive sampling and dual-column capillary GC-FID-a new feasible approach for the detection of an exposure to indoor mould fungi?. Journal of Environmental Monitoring, 1(5), Ghosh B, Lal H, and Srivastava A Review of bioaerosols in indoor environment with special reference to sampling, analysis and control mechanisms. Environment international, 85,

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