The adoption, implementation and enforcement of Chapter 27 of the EU acquis on Environment is an obligation for accessing countries. Reducing the emissions of air pollutants and greenhouse gases (GHG) is a priority which is strongly interlinked with energy, transport and health policies, among others. This report summarises the current status of air pollution and emission of pollutants and GHG in the countries of the Western Balkans (WB), describing the existing level of knowledge and the gaps with respect to the EU aquis in order to benchmark the future progress in this field, during the accession process. At present, the alignment with the EU acquis on environment and climate in the WB ranges from early stage to advanced. The implementation of Ambient Air Quality Directive is not fully effective in all the WB countries and air quality monitoring networks, online data processing and QA/QC procedures are at different levels of development. Often, air pollution reporting in the WB does not fulfil all the required criteria often and the number and proportion of reporting stations, time series and data coverage are all quite variable. Particulate matter (PM10 and PM2.5), SO2, O3 and NO2 are the air pollutants which levels are most frequently above the legislation limits in the WB. They are mainly emitted by human activities such as industry (including electricity production), household heating and transport. Agriculture contributes to secondary pollution. In addition, transboundary pollution from outside the region makes a considerable contribution to the observed concentrations. Energy and transport are the main sources of GHG in the region and a steady increase in the emissions is observed in some countries since 1995. The alignment in the field of climate change is at an initial stage. A continuing commitment is needed in the WB to achieve full alignment with EU environment acquis. The initial focus of the air quality management policies should be on the pollutants which are most frequently above the European legislation limit values. Among these are PM10, PM2.5 and SO2 emitted by coal burning in obsolete and inefficient power plants and industrial facilities. The combustion of biomass for residential heating also leads to considerable emissions of particulate matter. Co-benefits between air quality and climate should be better exploited. More effort should be made to further develop the technical skills in the WB countries in the areas of air quality monitoring and modelling and development of emission inventories for atmospheric pollutants and GHGs.