Characterization of Air Quality Problems in Five Finnish Indoor Ice Arenas

ABSTRACT

The air quality in five Finnish ice arenas with different volumes, ventilation systems, and resurfacer power sources (propane, gasoline, electric) was monitored during a usual training evening and a standardized, simulated ice hockey game. The measurements included continuous recording of carbon monoxide (CO), nitric oxide (NO), and nitrogen dioxide (NO₂) concentrations, and sampling and analysis of volatile organic compounds (VOCs). Emissions from the ice resurfacers with combustion engines caused indoor air quality problems in all ice arenas. The highest 1-hour average CO and NO₂ concentrations ranged from 20 to 33 mg/m³ (17 to 29 ppm) and 270 to 7440 µg/m³ (0.14 to 3.96 ppm), respectively. The 3-hour total VOC concentrations ranged from 150 to 1200 µg/m³. The highest CO and VOC levels were measured in the arena in which a gasoline-fueled resurfacer was used. The highest NO₂ levels were measured in small ice arenas with propane-fueled ice resurfacers and insufficient ventilation.

In these arenas, the indoor NO₂ levels were about 100 times the levels measured in ambient outdoor air, and the highest 1-hour concentrations were about 20 times the national and World Health Organization (WHO) health-based air quality guidelines. The air quality was fully acceptable only in the arena with an electric resurfacer. The present study showed that the air quality problems of indoor ice arenas may vary with the fuel type of resurfacer and the volume and ventilation of arena building. It also confirmed that there are severe air quality problems in Finnish ice arenas similar to those previously described in North America.     

Regulation of photochemical activity in cultured symbiotic dinoflagellates under nitrate limitation and deprivation

The effects of nitrate limitation and nitrate starvation on the photochemical efficiency of photosystem II (Fv/F m) were examined in batch cultures of two species of symbiotic dinoflagellates, Symbiodinium kawagutii and S. pilosum. F v/F m values were determined along growth curves and show that the F v/F m values are negatively correlated with external nitrogen concentrations in cultures of both species. Changes in growth irradiances in the batch cultures due to increments of the cell densities were estimated S. kawagutii cultures showed a negative correlation between F v/F m and growth irradiance. These results indicate that F v/F m is dependent on the light history of the cultures and on the individual sensitivity of each species, and independent of their nutrient status. Nitrate starvation was analyzed by measuring changes in the quantum yield of fluorescence (Fv/F m), electron transport rate (ETR) and non-photochemical quenching (NPQ) at five time points along the growth curves under three conditions: control (C), without nitrogen (N–), and with ammonia (N+) as a nitrogen source sufficient to meet daily nitrogen requirements. Cells collected during the exponential growth phase and exposed to N– and N+ showed significant reductions in their maximum ETR relative to controls (20% in S. pilosum and 40% in S. kawagutii). The loss of electron transport capacity is consistent with a sink limitation rather than the result of nitrogen starvation. Under nitrate-starvation, the induction of NPQ resulted in effective protection against photosystem II damage in S. pilosum. In contrast, S. kawagutii cells failed to induced NPQ resulting in a concomitant increase in the excitation pressure over photosystem II leading to damage. Collectively the data indicate that F v/F m is not a robust indicator of nitrogen limitation in symbiotic dinoflagellates and that protection against photosystem II damage under sink limitations, is largely dependent on the differential capacities of each species to induce NPQ.Communicated by P.W. Sammarco, Chauvin