Fine particles are a form of air pollution (excluding sea salt particles). When inhaled, fine particles may cause health problems like respiratory complaints or aggravate cardiovascular complaints. For particles with a diameter not exceeding 10 micrometres (PM10), the European norm for the annual average concentration is 40 micrograms per cubic metre and 50 micrograms per cubic metre for the average daily concentration. The daily norm must not be overstepped more than 35 times a year. Back to article