Ambient particulate matter: sources and apportioning

01 Oct 1999

The quality of the air we breathe has become an increasingly important and emotive issue over the past few years. To date, the regulation of air quality has focused mainly on outdoor air (even though for particular pollutants, indoor concentrations may be greater and exposures are often more significant—on average we may spend up to 90 per cent of our lives indoors). Ambient air quality standards have been established for many different pollutants, including standards for particulate matter in various countries.