Protection of the vehicle cab environment against bacteria, fungi and endotoxins in composting facilities

• Published in: Waste management (Elmsford) 2012-06, Vol.32 (6), p.1106-1115
• Main Authors: Schlosser, O., Huyard, A., Rybacki, D., Do Quang, Z.
• Format: Article
• Language: English
• Subjects: Air Microbiology; Air Pollution, Indoor - prevention & control; Applied sciences; Bacteria; Bioaerosols; Composting; Exact sciences and technology; Fungi; Health; Humans; Motor Vehicles; Occupational exposure; Occupational Exposure - prevention & control; Other wastes and particular components of wastes; Pollution; Risk Assessment; Sanitation - methods; Soil; Spores, Fungal; Vehicle cab; Waste Management - methods; Wastes
• ISSN: 0956-053X; 1879-2456
• DOI: 10.1016/j.wasman.2012.01.013

► Simultaneous air sampling was carried out both within and on the outside of eight vehicle cabs. ► The protection efficiency of vehicle cab was at it lowest when confronted with fungal spores. ► Pressurisation and HEPA filtration can provide a cab protection efficiency of more than 99.9%. ► This objective is only achievable if the cab is thoroughly cleaned and leakage of the filter-sealing system is limited. ► Fungi-related respiratory effects were checked, and the proposed endotoxin occupational exposure limit was not exceeded. Microbial quality of air inside vehicle cabs is a major occupational health risk management issue in composting facilities. Large differences and discrepancies in protection factors between vehicles and between biological agents have been reported. This study aimed at estimating the mean protection efficiency of the vehicle cab environment against bioaerosols with higher precision. In-cab measurement results were also analysed to ascertain whether or not these protection systems reduce workers’ exposure to tolerable levels. Five front-end loaders, one mobile mixer and two agricultural tractors pulling windrow turners were investigated. Four vehicles were fitted with a pressurisation and high efficiency particulate air (HEPA) filtration system. The four others were only equipped with pleated paper filter without pressurisation. Bacteria, fungi and endotoxins were measured in 72 pairs of air samples, simultaneously collected inside the cab and on the outside of the cab with a CIP 10-M sampler. A front-end loader, purchased a few weeks previously, fitted with a pressurisation and high efficiency particulate air (HEPA) filtration system, and with a clean cab, exhibited a mean protection efficiency of between 99.47% CI 95% [98.58–99.97%] and 99.91% [99.78–99.98%] depending on the biological agent. It is likely that the lower protection efficiency demonstrated in other vehicles was caused by penetration through the only moderately efficient filters, by the absence of pressurisation, by leakage in the filter-sealing system, and by re-suspension of particles which accumulated in dirty cabs. Mean protection efficiency in regards to bacteria and endotoxins ranged between 92.64% [81.87–97.89%] and 98.61% [97.41–99.38%], and between 92.68% [88.11–96.08%] and 98.43% [97.44–99.22%], respectively. The mean protection efficiency was the lowest when confronted with fungal spores, from 59.76% [4.19–90.75%] to 94.71% [91.07–97.37%]. The probability