in thE 3rD pArAgrAph thE writEr suggEsts thAt A pEoplE shoulD AvoiD working in CitiEs. B AmEriCAns spEnD too littlE timE outDoors. C hAzArDous gAsEs ArE ConCEntrAtED in inDustriAl suBurBs. D thErE ArE sEvErAl wAys to AvoiD City pollution.