Airpollutionisoneofthemajorproblemsofthemodernworld.Agreatdealofenergyisneededtorunthefactoriesofmodernindustrialnations.Automobile,trains,planesandbussesneedenergy,too.Nearlyallofthisenergyisproducedbyburningfuels.Theburningproduceswastes,someofwhichremainintheair,causingairpollution.

　　Scientistsarefindingwaystostopairpollutionespeciallyinbigindustrialareasanddensely-populatedcities.Theyarestudyingnewwaysofgeneratingelectricitythatmaybelessdamagingtotheenvironment.Inthemeantime,manypowerplantsarebeingmodernizedtogiveofflesspollutedmaterial.Also,engineerstrytodesignandlocatenewpowerplantstodominimumdamagetotheenvironment.

　　However,itmaybethatwestillhavealongwaytogobeforewehavea"clean"world.Nearlyallofthecountriesaretryinghardtopreventandcontrolairpollution.Thereindeedseemstobenoendtotasksthatenvironmentalistswillberequiredtodo.Peoplewillcontinuallyfindnewwaystocontrolpollution.