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.

Figure 1

Placement of IAQ samplers inside the participating HS gymnasium near wrestling mats (photo courtesy of L.N. Gonzalez, January 2019).

Figure 2

Respirable or coarse particulate matter (PM₁₀) count-to-estimated concentrations, mg m⁻³, for match #1 on 1/23/2019. Each team had ∼25 student-athletes and ∼5 coaches/staff (including the certified athletic trainers) present. Notes: values to the right of peaks above were the highest measured values (off y-axis). Varsity warm-up on mats started ∼17 : 50, then match (individual bouts) started ∼18 : 03 and ended ∼19 : 11; student-athletes and coaches completed clean-up/roll mats to ∼19 : 20.

Figure 3

Respirable or coarse particulate matter (PM₁₀) count-to-estimated concentrations, mg m⁻³, for match #2 on 1/30/2019. Each team had ∼25 student-athletes and ∼5 coaches/staff (including the certified athletic trainers) present. Notes: values to the right of peaks above were the highest measured values (off y-axis). Junior varsity match finished ∼17 : 40, varsity warm-up exercises on mats to ∼18 : 00, then match (individual bouts) started ∼18 : 00 and ended ∼19 : 24, and student-athletes and coaches clean-up/roll mats ∼19 : 24–19 : 29 (data loggers stopped by 19 : 30 on study days).

Figure 4

Respirable or coarse particulate matter (PM₁₀) and fine particulate matter (PM_2.5) count-to-estimated concentrations, mg m⁻³, and suggested impact of student-athlete activities, match #1, 1/23/2019. Each team had ∼25 student-athletes and ∼5 coaches/staff (including the certified athletic trainers) present. Notes: the blue arrows were takedown maneuvers; the green arrows were pins; and the purple arrows were when a takedown maneuver led to a pin. For 1/23/2019, varsity warm-up on mats started ∼17 : 50, then match (individual bouts) started ∼18 : 03 and ended ∼19 : 11; student-athletes and coaches completed clean-up/mats rolled to ∼19 : 20 (data loggers stopped by 19 : 30 on study days).

Figure 5

Respirable or coarse particulate matter (PM₁₀) and fine particulate matter (PM_2.5) count-to-estimated concentrations, mg m⁻³, and suggested impact of student-athlete activities, match #2, 1/30/2019. Each team had ∼25 student-athletes and ∼5 coaches/staff (including certified athletic trainers) present. Notes: values to the right of the peaks above were the highest measured values (off y-axis). The blue arrows were takedown maneuvers; the green arrows were pins; and the purple arrows were when a takedown maneuver led to a pin. For 1/30/2019, junior varsity match finished ∼17 : 40, varsity warm-up exercises on mats to ∼18 : 00, then match (individual bouts) started ∼18 : 00 and ended ∼19 : 24, and student-athletes and coaches clean-up/mats rolled ∼19 : 24–19 : 29 (data loggers stopped by 19 : 30 on study days).

Figure 6

Fine particulate matter (PM_2.5) count-to-estimated concentrations, mg m⁻³, for match #1 on 1/23/2019. Each team had about 25 student-athletes and five coaches/staff (including certified athletic trainers) present. Notes: varsity warm-up on mats started ∼17 : 50, then the match (individual bouts) started ∼18 : 03 and ended ∼19 : 11; student-athletes and coaches completed clean-up/mats rolled to ∼19 : 20.

Figure 7

Fine particulate matter (PM_2.5) count-to-estimated concentrations, mg m⁻³, for match #2 on 1/30/2019. Each team had about 25 student-athletes and five coaches/staff (including certified athletic trainers) present. Notes: junior varsity match finished at ∼17 : 40, varsity warm-up exercises on mats to ∼18 : 00, then match (individual bouts) started ∼18 : 00 and ended ∼19 : 24, clean-up/mats rolled to ∼19 : 24–19 : 29 (data loggers stopped by 19 : 30).