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Effect of ultraviolet germicidal lights installed in office ventilation systems on workers' health and wellbeing: double-blind multiple crossover trial.

Authors
Menzies-D; Popa-J; Hanley-JA; Rand-T; Milton-DK
Source
Lancet 2003 Nov; 362(9398):1785-1791
NIOSHTIC No.
20029221
Abstract
Workers in modern office buildings frequently have unexplained work-related symptoms or combinations of symptoms. We assessed whether ultraviolet germicidal irradiation (UVGI) of drip pans and cooling coils within ventilation systems of office buildings would reduce microbial contamination, and thus occupants' work-related symptoms. We undertook a double blind, multiple crossover trial of 771 participants. In office buildings in Montreal, Canada, UVGI was alternately off for 12 weeks, then turned on for 4 weeks. We did this three times with UVGI on and three times with it off, for 48 consecutive weeks. Primary outcomes of self-reported work-related symptoms, and secondary outcomes of endotoxin and viable microbial concentrations in air and on surfaces, and other environmental covariates were measured six times. Operation of UVGI resulted in 99% (95% CI 67-100) reduction of microbial and endotoxin concentrations on irradiated surfaces within the ventilation systems. 771 participants appeared to remain masked, and reported no adverse effects. On the basis of within-person estimates, use of UVGI was associated with significantly fewer work-related symptoms overall (adjusted odds ratio 0.8 [95% CI 0.7-0.99]), as well as respiratory (0.6 [0.4-0.9]) and mucosal (0.7 [0.6-0.9]) symptoms than was non-use. Reduction of work-related mucosal symptoms was greatest among atopic workers (0.6 [0.5-0.8]), and never-smokers (0.7 [0.5-0.9]). With UVGI on, never-smokers also had large reduction of work-related respiratory (0.4 [0.2-0.9]), and musculoskeletal symptoms (0.5 [0.3-0.9]). Installation of UGVI in most North American offices could resolve work-related symptoms in about 4 million employees, caused by microbial contamination of heating, ventilation, and air-conditioning systems. The cost of UVGI installation could in the long run prove cost-effective compared with the yearly losses from absence because of building-related illness.
Keywords
Ultraviolet-light; Ventilation-systems; Worker-health; Occupational-health; Office-workers; Microbial-test-systems; Endotoxins; Air-monitoring; Ventilation; Workplace-monitoring; Air-contamination; Air-conditioning; Occupational-diseases
Contact
Dr Dick Menzies, Respiratory Epidemiology Unit, Montreal Chest Institute, McGill University, 1110 Pine Avenue West, Room 103, Montreal, Quebec, Canada H3A 1A3
CODEN
LANCAO
Publication Date
20031129
Document Type
Journal Article
Email Address
dick.menzies@mcgill.ca
Funding Amount
48935
Funding Type
Grant
Fiscal Year
2004
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-003693
Issue of Publication
9398
ISSN
0140-6736
Priority Area
Work Environment and Workforce: Indoor Environment
Source Name
Lancet
State
MA
Performing Organization
McGill University, Montreal, Quebec, Canada
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