Fig. 3

Annual average PM2.5 concentration caused by aviation activities at each airport from January 2006 to December 2023. (a) 2006. (b) 2007. (c) 2008. (d) 2009. (e) 2010. (f) 2011. (g) 2012. (h) 2013. (i) 2014. (j) 2015. (k) 2016. (l) 2017. (m) 2018. (n) 2019. (o) 2020. (p) 2021. (q) 2022. (r) 2023.