| Number Concentration and Size of Particles in Urban Air: Effects on Spirometric Lung Function in Adult Asthmatic Subjects Pasi Penttinen,1 Kirsi Liisa Timonen,1 Pekka Tiittanen,1 Aadu Mirme,2 Juhani Ruuskanen,3 and Juha Pekkanen1 1Unit of Environmental Epidemiology, National Public Health Institute, Kuopio, Finland
2Institute of Environmental Physics, University of Tartu, Tartu, Estonia
3Department of Environmental Sciences, University of Kuopio, Kuopio, Finland Abstract
Daily variations in ambient particulate air pollution are associated with variations in respiratory lung function. It has been suggested that the effects of particulate matter may be due to particles in the ultrafine (0.01-0.1 µm) size range. Because previous studies on ultrafine particles only used self-monitored peak expiratory flow rate (PEFR) , we assessed the associations between particle mass and number concentrations in several size ranges measured at a central site and measured (biweekly) spirometric lung function among a group of 54 adult asthmatics (n = 495 measurements) . We also compared results to daily morning, afternoon, and evening PEFR measurements done at home (n = 7,672-8,110 measurements) . The median (maximum) 24 hr number concentrations were 14,500/cm3 (46,500/cm3) ultrafine particles and 800/cm3 (2,800/cm3) accumulation mode (0.1-1 µm) particles. The median (maximum) mass concentration of PM2.5 (particulate matter < 2.5 µm) and PM10 (particulate matter < 10 µm in aerodynamic diameter) were 8.4 µg/m3 (38.3 µg/m3) and 13.5 µg/m3 (73.7 µg/m3) , respectively. The number of accumulation mode particles was consistently inversely associated with PEFR in spirometry. Inverse, but nonsignificant, associations were observed with ultrafine particles, and no associations were observed with large particles (PM10) . Compared to the effect estimates for self-monitored PEFR, the effect estimates for spirometric PEFR tended to be larger. The standard errors were also larger, probably due to the lower number of spirometric measurements. The present results support the need to monitor the particle number and size distributions in urban air in addition to mass. Key words: air pollution, asthma, FVC, FEV1, particles, particle size, peak expiratory flow rate, PEFR, spirometry. Environ Health Perspect 109:319-323 (2001) . [Online 7 March 2001] http://ehpnet1.niehs.nih.gov/docs/2001/109p319-323penttinen/ abstract.html Address correspondence to J. Pekkanen, National Public Health Institute, P.O. Box 95, 70701 Kuopio, Finland. Telephone: +358-17-201368. Fax: +358-17-201265. We thank S. Penttinen and J. Hosiokangas for their commitment in the fieldwork. The study was done within the framework of the Exposure and Risk Assessment for Fine and Ultrafine Particles in Ambient Air (ULTRA) project. The project was funded by European Union Environment and Climate Research Programme contracts ENV4-CT96-0205 and ENV4-CT97-0568 and the Academy of Finland. The project was coordinated by the Unit of Environmental Epidemiology, National Public Health Institute, Kuopio, Finland. The North-Savo Cultural Foundation supported P. Penttinen financially. Received 3 July 2000 ; accepted 10 October 2000.
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