<p>Elevated atmospheric ammonia (NH₃) concentrations have been reported in the Athabasca Oil Sands Region of Alberta, although the source of these emissions is uncertain. We compiled monthly atmospheric NH₃ data obtained by passive samplers at 45 sites over a 4-year period and found that NH₃ concentrations were greatly elevated above background levels in the summer and were positively correlated with air temperature at sites close (&lt; 15&#xa0;km, n = 16) as well as at sites distant (&gt; 15&#xa0;km, n = 29) from the center of industrial activities. Natural surface waters in the region have not been previously considered as potential NH₃ sources even though the region is dominated by wetlands and small lakes. Measurements of 66 of these lakes showed that 30% have a pH &gt; 8.0 with 3% having a pH &gt; 9.0 that are expected to contain appreciable amounts of NH₃ that can be released to the atmosphere under summertime conditions. Further, most lakes are less than 3&#xa0;m deep and total Kjeldahl N could be as high as 3.5&#xa0;mg&#xa0;L⁻¹ in shallow lakes and the temperature of the lakes can exceed 20&#xa0;°C in summer, promoting organic matter mineralization and the production of NH₄⁺. We suggest that these conditions can promote the release of NH₃ from natural waterbodies as well as tailings ponds in the summertime and explain the spatial patterns in atmospheric NH₃ that are observed regionally. These emissions need to be better characterized in further studies.</p>