Enhanced particle filtration in a non-problem office environment: preliminary results from a double-blind crossover intervention study.
Mendell-MJ; Fisk-WJ; Dong-MX; Petersen-M; Hines-CJ; Faulkner-D; Deddens-JA; Ruder-AM; Sullivan-D; Boeniger-MF
Am J Ind Med 1999 Sep; 36(S1):55-57
Although chance effects could be excluded only for the confusion scale and environmental stuffiness, enhanced particle filtration in this building was associated with small improvements in 10 of the 13 worker outcome measures. Findings of only slight beneficial effects from removing small airborne particles in this building may not apply to buildings with higher symptom levels, lower ventilation rates, or significant microbiologic contamination. Temperatures, not experimentally manipulated, were generally within the comfort range; however, the positive relation seen between temperatures and most of the adverse outcomes suggests substantial occupant benefits from lower temperatures even within the accepted comfort range. Study strengths included the double-blind, crossover intervention design and analyses of changes within subjects. Although uncontrolled factors varying over time may have biased findings, among measured factors only temperature was made in the analyses. Participants were not randomly allocated to experimental groups, but the crossover design reduced the potential resulting bias. If effects of enhanced filtration began after or lasted more than a week, findings could have been distorted. Health outcomes potentially related to particles other than acute symptoms were not assessed. Studying a building without excess symptoms or contaminants reduced the chance of finding filtration benefits; however, small effects in such a building, if replicated, will be more generalizable than results in a heavily contaminated building. Similar blinded, controlled, crossover studies can assess whether filtration or other reversible interventions produce larger benefits in buildings with suspected particulate contamination or higher symptom levels.
Epidemiology; Particulate-dust; Particulates; Airborne-dusts; Airborne-fibers; Airborne-particles; Air-quality-control; Air-quality-monitoring; Air-quality-measurement; Air-purification; Air-monitoring; Air-filters; Air-conditioning; Air-conditioning-equipment; Respirable-dust; Statistical-analysis; Office-workers; Office-equipment; Analytical-processes; Analytical-methods; Ventilation-systems; Work-environment; Closed-building-syndrome; Indoor-air-pollution; Work-environment; Filtration; Air-contamination; Indoor-environmental-quality
M.J. Mendell, NIOSH, 4676 Columbia Pkwy, R-16, Cincinnati, OH 45226
American Journal of Industrial Medicine