Long-term associations of PM1 versus PM2.5 and PM10 with asthma and asthma-related respiratory symptoms in the middle-aged and elderly population oleh Xue-yan Zheng, Shu-jun Guo, Jian-xiong Hu, Rui-lin Meng, Yan-jun Xu, Yun-hong Lv, Ye Wang, Ni Xiao, Chuan Li, Xiao-jun Xu, De-jian Zhao, Hong-ye Zhou, Jia-hui He, Xiao-min Tan, Jing Wei, Li-feng Lin, Wei-jie Guan