The need to separate impurities from air or other gases has increased as regards both the degree of separation and the necessity to separate both gases and finer particles. Correct specification of filters is a prerequisite for the correct functioning of ventilation systems, for sensitive production or to protect humans and the environment and to improve indoor air quality. Global climate change is an important issue and it is important for Eurovent to support the efforts in the Energy Performance of Building Directive (EPBD) and at the same time consider the effect of indoor air quality. Eurovent has always led the field in measuring and characterising air filters and provided the basis for common European Standards. This document is available in English.