Short-term effects of combined environmental factors on respiratory disease mortality in Qingdao city: A time-series investigation - Xin Zhang; Zijian Xi; Min Yang; Xiuqin Zhang; Ruikai Wu; Shuang Li; Lu Pan; Yuan Fang; Peng Lv; Yan Ma; Haiping Duan; Bingling Wang; et al. (PLoS ONE, 2025)