The Western Balkans (WB) is a region in South-East Europe where the alignment of national legislations and policies with those of the European Union (EU) is in progress with the prospect of achieving the EU membership. Such process is crucial for air quality management considering that the levels of air pollution in this area are among the highest of Europe and affect neighbouring regions. With the aim of informing the design of air quality policies in the WB, the TM5-FAst Scenario Screening Tool (TM5- FASST) was used to estimate the trends of air quality (PM 2.5 and ozone) impacts on health, crops yields and climate from 2000 to 2050. To that end, five ECLIPSE V6b emission scenarios with different assumptions on population growth, deployment of technologies and policies were compared. The measures in the current legislation baseline (CLE) are effective in abating the projected impact of energy, transport and domestic sectors on air quality while they show little effect on agriculture and waste sectors. The implementation of the maximum feasible reduction (MFR) scenarios in the WB would lead to a decrease in the mortality associated with PM 2.5 of 49%–65% in 2050 compared to CLE. On the contrary, no further control (NFC) scenarios would cause an increase in PM 2.5 mortality of 16%–21% in 2050 compared to CLE. The analysis of the mortality associated with transboundary pollution suggests that lack of action would lead to a considerable increase in the impact of WB emissions on neighbouring countries. The MFR scenario would also lead to a reduction of the agricultural losses due to ozone pollution of 38%–90% in 2050 compared to the CLE. The global warming potential on a 20-years’ timescale was assessed to estimate the medium term impact of air pollutants’ emission reduction on climate. In the CLE it would increase by 110 CO 2 eq Tg by 2050 compared to 2000 and it could be mitigated by measures in line with the Paris Agreement 2°C target and the UN sustainable development goals (e.g. on energy transition and depollution). The scenarios analysed depict a spectre ranging from the maximum benefits of combining ambitious air quality and climate policies to the impact of no implementing the currently adopted ones that provides a reference framework for the development of sustainable policies in the region.