Correlation of ambient inhalable bioaerosols with particulate matter and ozone: A two-year study Atin Adhikari, Tiina Reponen * , Sergey A. Grinshpun, Dainius Martuzevicius 1 , Grace LeMasters Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267-0056, USA Received 8 December 2004; accepted 1 July 2005 Synergistic effects of these pollutants may increase incidence of respiratory health problem. Abstract In this study, we have examined the relationships between the concentrations of ambient inhalable airborne fungi and pollen with PM 10 , PM 2.5 , ozone, organic carbon, selected trace metals (cadmium, copper, lead, and zinc), temperature, and relative humidity. The database was collected in Cincinnati, Ohio, USA, during two consecutive years. Measurements of all environmental variables were performed at the same site continuously 5 days a week except during winter months. The airborne concentrations of biological and non-biological pollutants ranged as follows: total fungi: 184e16 979 spores m ÿ3 ; total pollen: 0e6692 pollen m ÿ3 ; PM 10 : 6.70e 65.38 mgm ÿ3 ; PM 2.5 : 5.04e45.02 mgm ÿ3 ; and ozone: 2.54e64.17 ppb. Higher levels of total inhalable fungi and particulate matter were found during fall and summer months. In contrast, total pollen concentration showed elevated levels in spring. Peak concentrations of ozone were observed during summer and beginning of fall. Our study concluded that several types of inhalable airborne fungi and pollen, particulate matter, and ozone could be positively correlated as a result of the atmospheric temperature influence. Ó 2005 Elsevier Ltd. All rights reserved. Keywords: Inhalable bioaerosol; Aeroallergen; PM 10 and PM 2.5 ; Ozone; Air pollutants 1. Introduction There is a lack of investigations on ambient inhalable bioaerosols and little attention has been paid on the interrelationships between allergenic inhalable bioaer- osols, ambient air pollutants relevant to respiratory health, and meteorological factors. A significant portion of atmospheric aerosol is of biological origin. Approx- imately 24% of the count of total atmospheric particles and 5e10% of the total suspended particulate mass were reported to be contributed by bioaerosols (Matthias- Maser and Jaenicke, 1995; Glikson et al., 1995). Based on the concentration of phospholipids, Womiloju et al. (2003) reported that cell materials of fungi and pollen could contribute 4e11% of the total PM 2.5 mass and 12e22% of organic carbon in fine particulate matter. Among different bioaerosol components, airborne fungi and pollen grains are associated with respiratory allergic diseases and asthma (D’Amato et al., 1998; * Corresponding author. Center for Health-Related Aerosol Studies, Department of Environmental Health, University of Cincinnati, P.O. Box 670056, 3223 Eden Avenue, Cincinnati, OH 45267-0056, USA. Tel.: C1 513 558 0571; fax: C1 513 558 2263. E-mail address: tiina.reponen@uc.edu (T. Reponen). 1 On leave from the Department of Environmental Engineering, Kaunas University of Technology, Kaunas, Lithuania. 0269-7491/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.envpol.2005.07.004 Environmental Pollution 140 (2006) 16e28 www.elsevier.com/locate/envpol