Air pollution and dry deposition of nitrogen and sulphur in the AOSR estimated using passive samplers

Abstract

NO₂ and SO₂ are the primary pollutants produced by industrial facilities of the Athabasca Oil sand Region (AOSR), Alberta, Canada. The major emission sources are the upgrader stacks for SO₂ and stacks, mine fleets and vehicles for NO₂. After emitting from the sources, NO₂ and SO₂ undergo dilution and chemical reaction. The highest NO₂ and SO₂ deposition occurred in major industrial operation areas and Fort McMurray. However, concentrations of NH₃ and HNO₃ were also greater outside of the AOSR industrial activities, mainly in its southern part. Ammonia increased levels were possibly also caused by forest fires and agricultural activities in central Alberta. Nitric acid, as the secondary pollutant produced via photochemical reactions, was found at distances from the main NOx emission sources both in the northern and southern directions. Consequently, deposition of these pollutants as well as deposition of total gaseous inorganic N was also greater in those areas. The NH₄+ deposition calculated from the passive sampler data with the multi-layer model (MLM) and determined with the IER (ion exchange resins) open/throughfall sampling had similar patterns at all sampling sites. The NO₃- deposition results from two methods were similar. However, SO₂ dry deposition calculated with the MLM was much lower than that from the IER sampling. Further study is needed to reduce uncertainty for SO₂ dry deposition estimation.

Citation

Hsu, Yu-Mei; Bytnerowicz, Andrzej. 2015. Air pollution and dry deposition of nitrogen and sulphur in the AOSR estimated using passive samplers. In: Clair, T.A.; Percy, K.E., eds. Assessing forest health in the Athabasca Oil Sands Region. WBEA Technical Report: 8-39. Chapter 2.