Itwasoncethoughtthatairpollutionaffectedonlytheareaimme...
问题详情：Itwasoncethoughtthatairpollutionaffectedonlytheareaimmediatelyaroundlargecitieswithfactoriesand/orheavyautomobiletraffic.Today,weknowthatalthoughthesearetheareaswiththeworstairpollution,thepro...