On a mildly warm, sunny day on Chicago&amp;#8217;s South Side, a group of six avid runners and their mascot dog, Sadie-a chocolate lab and spaniel mix-gather together at the corner of 59th and Cottage Grove. The group&amp;#8217;s organizer, Paige Troelstrup, pulls out trash bags and latex gloves, giving one of each to everyone. The Chicago [...]