biostudies-literatureUnknown383Liu C<h4>Objective</h4>To investigate potential interactive effects of fine particulate matter (PM_2.5) and ozone (O₃) on daily mortality at global level.<h4>Design</h4>Two stage time series analysis.<h4>Setting</h4>372 cities across 19 countries and regions.<h4>Population</h4>Daily counts of deaths from all causes, cardiovascular disease, and respiratory disease.<h4>Main outcome measure</h4>Daily mortality data during 1994-2020. Stratified analyses by co-pollutant exposures and synergy index (>1 denotes the combined effect of pollutants is greater than individual effects) were applied to explore the interaction between PM_2.5 and O₃ in association with mortality.<h4>Results</h4>During the study period across the 372 cities, 19.3 million deaths were attBMJ (Clinical research ed.)e075203https://www.ebi.ac.uk/biostudies/studies/S-EPMC10548261biostudies-literatureInteractive effects of ambient fine particulate matter and ozone on daily mortality in 372 cities: two stage time series analysis.PMC10548261Pascal MGuo YRyti NZanobetti AMasselot PAchilleos SRaz RRoye DMayvaneh FTobias AMadureira JSchneider ANg CFSIniguez CChen RPan SCSera FTong SCorrea PMHashizume MBell MLGaio VVicedo-Cabrera AMSchwartz JHolobaca IHGasparrini AKan HOrtega NVBreitner SLavigne EEntezari AJaakkola JJGuo YLHonda YLiu CfalseInteractive effects of ambient fine particulate matter and ozone on daily mortality in 372 cities: two stage time series analysis.<h4>Objective</h4>To investigate potential interactive effects of fine particulate matter (PM_2.5) and ozone (O₃) on daily mortality at global level.<h4>Design</h4>Two stage time series analysis.<h4>Setting</h4>372 cities across 19 countries and regions.<h4>Population</h4>Daily counts of deaths from all causes, cardiovascular disease, and respiratory disease.<h4>Main outcome measure</h4>Daily mortality data during 1994-2020. Stratified analyses by co-pollutant exposures and synergy index (>1 denotes the combined effect of pollutants is greater than individual effects) were applied to explore the interaction between PM_2.5 and O₃ in association with mortality.<h4>Results</h4>During the study period across the 372 cities, 19.3 million deaths were att2023-01-01T00:00:00Z2023 Oct2025-04-18T13:25:19.958Z2025-04-04T08:46:17.64ZS-EPMC105482613779369510.1136/bmj-2023-075203