[Suspended particulates and lung health]

Abstract

Based on several severe air pollution episodes, a temporal correlation between high concentrations of particulate matter (PM) and SO2 pollution and acute increases in respiratory and cardiopulmonary mortality had been established in Vienna for the 1970's. After air pollution had decreased in Austria in the 1980's--as documented by data on SO2, and total suspended particles (TSP)--no such associations between day-to-day changes of SO2 and TSP and mortality have been documented any more, however, traffic related pollutants like fine particles and NO2 remained a problem. Therefore, short term effects of PM on lung function, morbidity and mortality were investigated in Vienna, Linz, Graz and a rural control area. Long-term exposure and chronic disease--even more important for public health--were studied in repeated cross-sectional, a mixed longitudinal and a birth cohort study on school children in the city of Linz. Lung function growth was found impaired from long-term exposure to air pollutants and improved in districts where ambient air pollution had decreased. Where only TSP and SO2 had decreased, no continuous improvement of small airway function was found and end-expiratory flow rates stayed impaired where NO2-reduction from technical improvements of cars and industry was counterbalanced by increase of motorized (diesel) traffic. Remaining acute effects of ambient air pollution in 2001 from PM, NO2 and co-pollutants found in a time series study also show that continuing efforts are necessary. Active surface of particles inhaled several hours to days before spirometry was found related to short-term reductions in forced vital capacity-FVC (p<0.01), forced expiratory volume in one second-FEV1 (p<0.01) and maximal expiratory flow rate at 50% of vital capacity-MEF50 (p<0.05). In pupils with asthma or previous airway obstruction 4-week-diaries proved that the following symptoms increased with acute exposure to higher active surface of particles: wheezing (p<0.01), dyspnea, cough when going to sleep, cough at night (p<0.05). Efforts to reduce exposure to fine particles from motor traffic and passive smoking have to be increased if we want to achieve full recovery of children from air pollution effects and best respiratory performance in adulthood. Surveillance seems to be necessary not only for particle mass but also for particle number and surface. Little is known on the mechanisms of irreversible long-term effects of PM such as myocardial infarction and cancer. In a prospective cohort study on 1630 dust-exposed and 1630 non dust-exposed workers matched for smoking we found an increase of lung cancer related to nonfibrous insoluble PM. Other studies were able to relate lung cancer to specific particles like those from diesel engines, and a large prospective study of the American Cancer Society was able to link lung cancer in the general population with long-term exposure to fine particles from combustion processes. All these recent epidemiological findings will have consequences for occupational and ambient air PM standards.