Time-Resolved Characterization of Indoor Air Quality due to Human Activity and Likely Outdoor Sources during Early Evening Secondary School Wrestling Matches

Abstract

Despite positive health outcomes associated with physical activity as well as individual and team sports, poor indoor air and environmental quality can adversely affect human health, performance, and comfort. We conducted a 14-month field case study incorporating two winter sports regular seasons (12/2017-2/2019) including analyses of particulate matter (PMx) in air and in dust, carbon dioxide (CO₂), temperature, and relative humidity (RH%) during secondary or high school wrestling activities in southern New Jersey, USA. After planning and piloting methods during the first winter sports regular season (12/2017-2/2018), during the second winter sports regular season (1-2/2019), we conducted a purposeful simultaneous real-time sampling midgymnasium adjacent to the wrestling mats. Gymnasium occupancy ranged 100-500 people. Data collected included inhalable PM₁₀ resuspended from floor mats, fine respirable PM_2.5, and indoor CO₂, temperature, and RH%. Short-term real-time elevated PM₁₀ levels were directly compared with simultaneously documented wrestling match bouts, e.g., student-athlete takedowns and pins. PM₁₀ and PM_2.5 levels were compared with other known documented activities indoors (e.g., snack bar) and sources outdoors (e.g., adjacent parking lot and major freeway). To understand CO₂, temperature, and RH% data, we characterized the HS gym mechanical ventilation system-no doors or windows outdoors-and recorded occupancy during match hours. Indoor CO₂ levels ranged ∼700-1000 ppm during match #1 on 1/23/2019 but ranged from ∼900 to 1900 ppm during match #2 on 1/30/2019, with >1000 ppm for the majority of the time (and throughout the entire varsity match when occupancy was at maximum). Future research should further characterize PM₁₀ constituents in mat dust and indoor air with larger samples of schools and matches.