کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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6321084 | 1619722 | 2016 | 11 صفحه PDF | دانلود رایگان |
- NH3, HNO3, NO2, and SO2 concentrations were characterized by passive measurements.
- Dry deposition fluxes of N and S were estimated by a multi-layer model.
- Spatial distributions of N and S dry deposition in the AOSR were determined.
Due to the potential ecological effects on terrestrial and aquatic ecosystems from atmospheric deposition in the Athabasca Oil Sands Region (AOSR), Alberta, Canada, this study was implemented to estimate atmospheric nitrogen (N) and sulfur (S) inputs. Passive samplers were used to measure ambient concentrations of ammonia (NH3), nitrogen dioxide (NO2), nitric acid/nitrous acid (HNO3/HONO), and sulfur dioxide (SO2) in the AOSR. Concentrations of NO2 and SO2 in winter were higher than those in summer, while seasonal differences of NH3 and HNO3/HONO showed an opposite trend, with higher values in summer. Concentrations of NH3, NO2 and SO2 were high close to the emission sources (oil sands operations and urban areas). NH3 concentrations were also elevated in the southern portion of the domain indicating possible agricultural and urban emission sources to the southwest. HNO3, an oxidation endpoint, showed wider ranges of concentrations and a larger spatial extent. Concentrations of NH3, NO2, HNO3/HONO and SO2 from passive measurements and their monthly deposition velocities calculated by a multi-layer inference model (MLM) were used to calculate dry deposition of N and S. NH3 contributed the largest fraction of deposited N across the network, ranging between 0.70-1.25 kg N haâ1 yrâ1, HNO3/HONO deposition ranged between 0.30-0.90 kg N haâ1 yrâ1, and NO2 deposition between 0.03-0.70 kg N haâ1 yrâ1. During the modeled period, average dry deposition of the inorganic gaseous N species ranged between 1.03 and 2.85 kg N haâ1 yrâ1 and SO4-S deposition ranged between 0.26 and 2.04 kg haâ1 yrâ1. Comparisons with co-measured ion exchange resin throughfall data (8.51 kg S haâ1 yrâ1) indicate that modeled dry deposition combined with measured wet deposition (1.37 kg S haâ1 yrâ1) underestimated S deposition. Gas phase NH3 (71%) and HNO3 plus NO2 (79%) dry deposition fluxes dominated the total deposition of NH4-N and NO3-N, respectively.
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Journal: Science of The Total Environment - Volume 568, 15 October 2016, Pages 285-295