2020 | 80% | | 2015 25% | | 58% | 2017 30 % | 40% | | | | | | | | | | | | | | | | | | | | | | | | | | PM 2.5 | | | 2020 | 2015 15% | | PM 2.5 2015 | 18 % | 80 % | | 2015 25 % | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |