Personal exposure to traffic-related air pollutants and relationships with respiratory symptoms and oxidative stress: A pilot cross-sectional study among urban green space workers, Guilbert, Ariane, De Cremer Koen, Heene Billie, Demoury Claire, Aerts Raf, Declerck Priscilla, Brasseur Olivier, and Van Nieuwenhuyse An , Science of The Total Environment, Jan-02-2019, Volume 649, Number 628, (2019)