Short Communication Size distributions of total airborne particles and bioaerosols in a municipal composting facility Jeong Hoon Byeon, Chul Woo Park, Ki Young Yoon, Jae Hong Park, Jungho Hwang * School of Mechanical Engineering, Yonsei University, Seoul 120-749, Republic of Korea Received 18 July 2007; received in revised form 5 September 2007; accepted 7 September 2007 Available online 22 October 2007 Abstract Size distributions of total airborne particles and bioaerosols were measured in a full-scale composting facility, using an optical particle counter and an agar-inserted six-stage impactor, respectively. Higher concentrations of total airborne particles and bioaerosols were detected at a sampling location near the screening process preceded by the composting process than at sampling locations in the com- posting process. At the sampling location near the screening process, the concentrations of total airborne particles were approximately 10 8 particles/m 3 at the size of 0.3 lm and 10 5 particles/m 3 at 6.2 lm. The concentration of bioaerosols was about 10 4 CFU/m 3 in each stage of P7.0 lm (1st stage), 7.0–4.7 lm (2nd), 4.7–3.3 lm (3rd), 3.3–2.1 lm (4th), 2.1–1.1 lm (5th) and 1.1–0.65 lm (6th). Most of sub- micron particles smaller than 1 lm among the total airborne particles were believed to originate from the ambient air. Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Size distribution; Total airborne particles; Bioaerosols; Composting facility 1. Introduction The process of waste decomposition in composting facil- ities releases a variety of airborne particles, including bio- aerosols (Folmsbee and Strevett, 1999; Laine et al., 1999; Prasad et al., 2004; Taha et al., 2005). In fact, a large pro- portion of municipal waste is subject to rot, and is readily colonized by both bacteria and fungi (Liang et al., 2006; Kader et al., 2007). Upon the handling of such wastes, these bacteria and fungi can be aerosolized (i.e., form bio- aerosols), and may present infectious, allergenic, or toxic hazards (Lavoie et al., 2006). In a previous report, Folms- bee and Strevett (1999) determined the total concentrations of bacteria, fungi, and actinomycetes at a composting facil- ity. Laine et al. (1999) and Tolvanen and Ha ¨nninen (2005) measured the mass concentrations of total airborne parti- cles and colony-forming unit (CFU) bioaerosol concentra- tion. Although the size distributions of both total airborne particles and bioaerosols are crucial for the design of opti- mal dust emission control devices in composting facilities, no relevant data are currently available on the subject. In this study, number concentrations of total airborne parti- cles and bioaerosols as a function of particle size were mea- sured at a full-scale municipal composting facility, using an optical particle counter and an agar-inserted six-stage impactor, respectively. 2. Experimental This study was conducted at a full-scale composting facility in Incheon City, Korea, with a treatment capacity of 24 tons of food waste per day. The composting processes took place in an industrial warehouse-type composting facility, with occasional turning over a 15-day period. The compost piles were then stored in a static state for an additional 20–25 days. Air temperature–relative humidity, ammonia concentra- tion, and total odors were measured using a thermo- hygrometer (Testo 605, Testo AG, Germany), a real-time 0960-8524/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.biortech.2007.09.014 * Corresponding author. Tel.: +82 2 2123 2821; fax: +82 2 312 2821. E-mail address: hwangjh@yonsei.ac.kr (J. Hwang). Available online at www.sciencedirect.com Bioresource Technology 99 (2008) 5150–5154