Spatiotemporal variation in summer ground-level ozone in the Sandbanks Provincial Park, Ontario

摘要

Ground-level ozone (O3) is an atmospheric pollutant of concern owing to its impacts on both human and environmental health. In southern Ontario, Canada, air pollutants (including O3) are continuously monitored through a network of active monitoring stations; however, these stations are largely located in urban areas. Passive samplers for O3 and NO2 were deployed at 24 sites throughout the Sandbanks Provincial Park, on the shore of Lake Ontario during the summer of 2016 to assess the influence of lake-breeze circulation on air quality. Average O3 measured at the park (39.4?ppb) was higher than inland sites at Belleville (32.6?ppb) and Peterborough (30.0?ppb). A negative-linear relationship (R2?=?0.71) was observed between O3 concentration and distance from shore (500?m from Lake Ontario). While a positive-linear relationship was observed between exposure wind speed and O3 (R2?=?0.84) when the predominant wind direction was W–SW. The results suggest that the Sandbanks was influenced by lake-breeze circulation, resulting in elevated summertime O3. Similarly, average NO2 concentrations (4.3?ppb) were higher than the inland site at Peterborough (2.9?ppb), suggesting that lake-breeze circulation transported NO2 onshore from Lake Ontario. Elevated levels of O3 at the Sandbanks may be a potential concern for human health; moreover, estimated three-month AOT40 suggest that O3 may also damage vegetation.