RESPIRATORY EFFECTS ARE ASSOCIATED WITH THE NUMBER OF ULTRAFINE PARTICLES

The association between fine and ultrafine particles and respiratory h ealth was studied in adults with a history of asthma in Erfurt Eastern Germany, Twenty-seven nonsmoking asthmatics recorded their peak expir atory flow (PEF) and respiratory symptoms daily. The size distribution of ambient particles in the range of 0.01 to 2.5 mu m was determined with an aerosol spectrometer during the winter season 1991-1992, Most of the particles (73%) were in the ultrafine fraction (smaller than 0. 1 mu m in diameter), whereas moss: of the mass (82%) was attributable tee particles in the size range of 0.1 to 0.5 mu m. Because these two fractions did not have similar time courses (correlation coefficient r = 0.51), a comparison of their health effects was possible, Both frac tions were associated with a decrease of PEF and an increase in cough and feeling ill during the day. Health effects of the 5-d mean of the number of ultrafine particles were larger than those of the mass of th e fine particles, In addition, the effects of the number of the ultraf ine particles on PEF were stronger than those of particulate matter sm aller than 10 mu m (PM(10)). Therefore, the present study suggests tha t the size distribution of ambient particles helps to elucidate the pr operties of ambient aerosols responsible for health effects.