[contentcards url=”https://www.wsj.com/articles/air-quality-levels-drop-in-u-s-as-smoke-billows-from-canadian-wildfires-c87c53db?mod=hp_lead_pos7″ target=”_blank”] By Alyssa Lukpat, Paul Vieira and Erin Ailworth Haze triggers air-quality health warnings for millions of people and obscures the Empire State Building…