By SCOTT McFETRIDGE
DES MOINES, Iowa (AP) — Much of downtown Des Moines, Iowa, has been transformed in the past decade by new apartments, shops and restaurants, but a stench from animal processing plants still often lingers over all that shiny new development. Many other cities across the country are dealing with similar problems as angry residents deluge officials with complaints and file lawsuits. Companies have responded by installing new equipment, making payments to neighbors or even closing down. In Des Moines, officials recently began a comprehensive study that will lead to tighter regulations on some smelly manufacturing plants to finally clear the air.