Time trend of wet deposition acidifying potential at five ecological monitoring sites in eastern Canada 1981?1993

1995 ◽  
Vol 85 (2) ◽  
pp. 653-658 ◽  
Author(s):  
P. W. Summers
Keyword(s):  
Wet Deposition ◽  
Time Trend ◽  
Ecological Monitoring ◽  
Eastern Canada

scholarly journals Long-term air concentrations, wet deposition, and scavenging ratios of inorganic ions, HNO<sub>3</sub> and SO<sub>2</sub> and assessment of aerosol and precipitation acidity at Canadian rural locations

2016 ◽  
Author(s):  
Irene Cheng ◽  
Leiming Zhang
Keyword(s):  
Wet Deposition ◽  
Inorganic Ions ◽  
Anthropogenic Sources ◽  
Eastern Canada ◽  
Geographical Patterns ◽  
Nh3 Emission ◽  
Scavenging Ratios ◽  
Precipitation Acidity ◽  
Air Concentrations

Abstract. This study analyzed long-term air concentrations and annual wet deposition of inorganic ions and aerosol and precipitation acidity at 30 Canadian sites from 1983–2011. Scavenging ratios of inorganic ions and relative contributions of particulate- and gas-phase species to NH4+, NO3−, and SO42− wet deposition were determined. Long-term median atmospheric NH4+, NO3−, and SO42− between sites ranged from 0.1–1.7, 0.03–2.0, and 0.6–3.5 μg m−3, respectively. Their median annual wet deposition varied from 0.2–5.8, 0.8–23.3, and 0.8–26.6 kg ha−1 a−1. Geographical patterns of atmospheric Ca2+, Na+, Cl−, NH4+, NO3−, and SO42− were similar to wet deposition and attributed to anthropogenic sources, sea-salt emissions, and agricultural emissions. Decreasing trends in atmospheric NH4+ (1994–2010) and SO42− (1983–2010) were prevalent. Atmospheric NO3− increased from 1991–2001 and declined from 2001–2010. These results are consistent with SO2, NOx and NH3 emission trends in Canada and the U.S. Widespread declines in annual NO3− and SO42− wet deposition ranged from 0.07–1.0 kg ha−1 a−1 (1984–2011). Acidic aerosols and precipitation impacted southern and eastern Canada more than western Canada; however both trends have been decreasing since 1994. Scavenging ratios of particulate NH4+, SO42− and NO3− differed from literature values by 22 %, 44 % and a factor of 6, respectively, because of the exclusion of gas scavenging. Average gas and particle scavenging contributions to wet NO3− deposition were 72±23 % for HNO3 and 28±23 % for particulate NO3−. SO2 and particulate SO42− contributed 37±20 % and 63±20 % to wet SO42− deposition, respectively. NH3 and particulate NH4+ contributed 30±19 % and 70±19 % to wet NH4+ deposition.

scholarly journals Long-term air concentrations, wet deposition, and scavenging ratios of inorganic ions, HNO<sub>3</sub>, and SO<sub>2</sub> and assessment of aerosol and precipitation acidity at Canadian rural locations

2017 ◽  
Vol 17 (7) ◽  
pp. 4711-4730 ◽  
Author(s):  
Irene Cheng ◽  
Leiming Zhang
Keyword(s):  
Wet Deposition ◽  
Inorganic Ions ◽  
Anthropogenic Sources ◽  
Eastern Canada ◽  
Geographical Patterns ◽  
Nh3 Emission ◽  
Scavenging Ratios ◽  
Precipitation Acidity ◽  
Air Concentrations

Abstract. This study analyzed long-term air concentrations and annual wet deposition of inorganic ions and aerosol and precipitation acidity at 31 Canadian sites from 1983 to 2011. Scavenging ratios of inorganic ions and relative contributions of particulate- and gas-phase species to NH4+, NO3−, and SO42− wet deposition were determined. Geographical patterns of atmospheric Ca2+, Na+, Cl−, NH4+, NO3−, and SO42− were similar to wet deposition and attributed to anthropogenic sources, sea-salt emissions, and agricultural emissions. Decreasing trends in atmospheric NH4+ (1994–2010) and SO42− (1983–2010) were prevalent. Atmospheric NO3− increased prior to 2001 and then declined afterwards. These results are consistent with SO2, NOx and NH3 emission trends in Canada and the USA. Widespread declines in annual NO3− and SO42− wet deposition ranged from 0.07 to 1.0 kg ha−1 a−1 (1984–2011). Acidic aerosols and precipitation impacted southern and eastern Canada more than western Canada; however, both trends have been decreasing since 1994. Scavenging ratios of particulate NH4+, SO42− and NO3− differed from literature values by 22 %, 44 %, and a factor of 6, respectively, because of the exclusion of gas scavenging in previous studies. Average gas and particle scavenging contributions to total wet deposition were estimated to be 72 % for HNO3 and 28 % for particulate NO3−, 37 % for SO2 and 63 % for particulate SO42−, and 30 % for NH3 and 70 % for particulate NH4+.

scholarly journals Isotopic evidence of trace metal sources and transport in eastern Canada as recorded from wet deposition

2000 ◽  
Vol 105 (D10) ◽  
pp. 12263-12278 ◽  
Author(s):  
Antonio Simonetti ◽  
Clément Gariépy ◽  
Jean Carignan ◽  
Laurier Poissant
Keyword(s):  
Trace Metal ◽  
Wet Deposition ◽  
Eastern Canada ◽  
Isotopic Evidence ◽  
Metal Sources

Use of chemotherapy for early breast cancer in Germany, 2008-2017: A nationwide time-trend analysis

2020 ◽  
Author(s):  
F Riedel ◽  
AS Hoffmann ◽  
M Moderow ◽  
S Heublein ◽  
T Deutsch ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Trend Analysis ◽  
Early Breast Cancer ◽  
Time Trend

Seasonal diving and foraging behaviour of Eastern Canada-West Greenland bowhead whales

2020 ◽  
Vol 643 ◽  
pp. 197-217 ◽  
Author(s):  
SME Fortune ◽  
SH Ferguson ◽  
AW Trites ◽  
B LeBlanc ◽  
V LeMay ◽  
...  
Keyword(s):  
Climate Change ◽  
Late Summer ◽  
Calanoid Copepods ◽  
Eastern Canada ◽  
West Greenland ◽  
Bowhead Whales ◽  
Seasonal Movement ◽  
Dive Behaviour ◽  
Calanus Glacialis ◽  
Canada West

Climate change may affect the foraging success of bowhead whales Balaena mysticetus by altering the diversity and abundance of zooplankton species available as food. However, assessing climate-induced impacts first requires documenting feeding conditions under current environmental conditions. We collected seasonal movement and dive-behaviour data from 25 Eastern Canada-West Greenland bowheads instrumented with time-depth telemetry tags and used state-space models to examine whale movements and dive behaviours. Zooplankton samples were also collected in Cumberland Sound (CS) to determine species composition and biomass. We found that CS was used seasonally by 14 of the 25 tagged whales. Area-restricted movement was the dominant behaviour in CS, suggesting that the tagged whales allocated considerable time to feeding. Prey sampling data suggested that bowheads were exploiting energy-rich Arctic copepods such as Calanus glacialis and C. hyperboreus during summer. Dive behaviour changed seasonally in CS. Most notably, probable feeding dives were substantially shallower during spring and summer compared to fall and winter. These seasonal changes in dive depths likely reflect changes in the vertical distribution of calanoid copepods, which are known to suspend development and overwinter at depth during fall and winter when availability of their phytoplankton prey is presumed to be lower. Overall, CS appears to be an important year-round foraging habitat for bowheads, but is particularly important during the late summer and fall. Whether CS will remain a reliable feeding area for bowhead whales under climate change is not yet known.

Changing Characteristics of Private-Hospital Alcoholic Patients. A Twenty-Year Time-Trend Analysis

1958 ◽  
Vol 19 (2) ◽  
pp. 309-315
Author(s):  
Milton A. Maxwell ◽  
Frederick Lemere ◽  
Paul O'Hollaren
Keyword(s):  
Trend Analysis ◽  
Time Trend ◽  
Private Hospital
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