PARTICULATE MATTER AIR-POLLUTION

Suspended particulate matter is strongly associated with parameters defining respiratory health. Besides the total mass of particulates, the size distribution is of importance. Definitions for the particle size distribution were standardised by CEN recently. The three major groups are defined as inhalable, thoracic and respirable fractions. In Switzerland, ambient total suspended particulates are measured since the mid seventies. Increasing concentrations were observed until the mid-eighties, but since then, levels were decreasing. In 1993, TSP levels in urban Swiss areas were higher than 40 mug.m-3, in suburban regions between 30 and 40 mug.m-3, in rural regions around 30 mug.m-3 and in alpine regions lower than 20 mug.m-3. In 1993, thoracic particles (PM10) were measured for the first time and concentrations ranged between 10 mug.m-3 (alpine) and 33 mug.m-3 (urban). Regional ratios between thoracic particles and total suspended particles were between 0.6 and 0.75. It is assumed that interactions between gaseous pollutants and particles with pollen can alter the allergenic potency.