The annual report ’Air quality in Europe’ summarises the most recent evaluation of Europe’s air quality status. It is mainly based on air quality measurement data that have been made available officially by 32 EEA member countries as well as 6 EEA cooperating countries. The report includes maps and analyses of air quality status over the calendar year 2009. It also analyses air quality trends over the past years. The evaluation of the status and trends of air quality is based on ambient air measurements, in conjunction with reported anthropogenic emissions. The report summarizes the main effects of different air pollutants on human health, the environment and the climate. An overview of policies and measures at European level is also given for each pollutant. This report reviews progress towards meeting the requirements of the two air quality directives in force as well as the air quality guidelines set by the World Health Organization (WHO). The report is produced in support of European and national policy development and implementation in the field of air quality. It also supports air quality management and informs the general public on the current status and trends of air quality in Europe.