Niilo R. I. Ryti is with the Center for Environmental and Respiratory Health Research (CERH), Faculty of Medicine, University of Oulu, and Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland. Jouni Nurmi, Ari Salo, and Markku Kuisma are with the Department of Emergency Medicine and Services, Helsinki University Hospital, Helsinki, Finland. Harri Antikainen is with the Geography Research Unit, University of Oulu. Jouni J. K. Jaakkola is with CERH, Faculty of...