High levels of airborne ultrafine and fine particulate matter in indoor ice arenas

The high prevalence of airway dysfunction among ice arena athletes may be related to rink air exposure; in particular, high concentrations of ultrafine and fine particulate matter (0.02-1.0 mum diameter, PM1) from ice resurfacing machines may enhance airway inflammation and hyperreactivity. The purpose of this study was to identify levels of PM1 emitted from ice resurfacing machines used in indoor ice arenas, and to compare [PM1] pre- and post-resurfacing to each other and to outdoor [PM1]. Multiple one Hz measurements were recorded on 28 different days as 15-s mean of PM1.cm(-3) for 2 min at 1-1.5 m "above ice" in 10 rinks pre- and post-resurfacing, with measured airborne PM1 outside each rink to be used individual rink references. Rink PM1.cm(-3) was similar to30 times greater than PM1.cm(-3) outside the respective rinks (p <.05). Rink values were 104.2 +/- 59.3 x 10(3) PM1 center dot cm(-3) during prime usage, compared to outdoor values of 3.8 +/- 2.5 x 10(3) PM1 center dot cm(-3). Ice resurfacing increased PM1 center dot cm(-3) 4-fold (p <.05). No difference in PM1 emissions between gasoline and propane powered resurfacing machines was identified. The rate of PM1 dissipation after resurfacing was highly variable between rinks and probably dependent upon rink ventilation and resurfacing machine engine efficiency. Gas-powered edging increased PM1.cm(-3) 18-fold and 158-fold versus pre-edging rink and outdoor values, respectively. We conclude that the primary source of airborne indoor rink PM1 is internal combustion ice-resurfacing machines and that this poor air quality may be causal to the unique and high prevalence of airway dysfunction in ice arena athletes.