Objective: to estimate the attributable and targeted avoidable deaths of outdoor air pollution by ambient PM10, PM2.5 and O3 according to specific WHO methodology. Design: health impact assessment. Setting:City of Valladolid, Spain (around 300.000 residents). Data sources: demographics; mortality; pollutant concentrations collected 1999-2008. Main outcome measures: attributable fractions (AFs); attributable and targeted avoidable deaths (ADs; TADs) per year for 1999 – 2008. Results: Higher TADs estimates (shown here) were obtained when assuming as “target” concentrations WHO Air Quality Guidelines instead of Directive 2008/50/EC. ADs are considered relative to pollutant background levels. All-causemortality associated to PM10 (all ages): 52 ADs (95% CI: 39-64); 31 TADs (95% CI: 24 – 39). All-causemortality associated to PM10 (<5 years): 0 ADs (95% CI: 0-1); 0 TADs (95% CI: 0 –1). All-causemortality associated to PM2.5 (> 30 years): 326 ADs (95% CI: 217-422); 231 TADs (95% CI: 153 - 301). Cardiopulmonary and lung cancer mortality associated to PM2.5 (>30 years): o Cardiopulmonary: 186 ADs (95% CI: 74-280) ; 94 TADs (95% CI: 36 – 148). o Lung cancer : 51 ADs (95% CI: 21-73); 27 TADs (95% CI: 10 – 41). All-cause, respiratory and cardiovascular mortality associated to O3(all ages): o All-cause: 52ADs (95% CI: 25-77) ; 31 TADs (95% CI: 15 – 45). o Respiratory : 5 ADs (95% CI : -2 – 13) ; 3 TADs (95%% CI : -1 – 8). o Cardiovascular: 30 ADs (95% CI: 8-51) ; 17 TADs (95% CI: 5 – 30). Negative estimates which should be read as zero were obtained when pollutant concentrations were below counterfactuals or assumed risk coefficients were below 1. Conclusions: Our estimates suggest a not negligible negative impact on mortality of outdoor air pollution. The implementation of WHO methodology provides critical information to distinguish an improvement range in air pollution control.