tokens: RESULTS : We observed positive associations of Parkinson ' s disease with ozone ( odds ratio = 1 . 39 ; 95 % CI : 0 . 98 to 1 . 98 ) and fine particulate matter ( odds ratio = 1 . 34 ; 95 % CI : 0 . 93 to 1 . 93 ) in North Carolina but not in Iowa .