A5051402420- Atmospheric chemistry and aerosols
- Air Quality and Health Impacts
- Atmospheric and Environmental Gas Dynamics
- Air Quality Monitoring and Forecasting
- Atmospheric Ozone and Climate
- Groundwater and Isotope Geochemistry
- Atmospheric aerosols and clouds
- Plant responses to elevated CO2
- Vehicle emissions and performance
- Soil and Water Nutrient Dynamics
- Water Quality and Resources Studies
- Marine and coastal ecosystems
- Odor and Emission Control Technologies
- Particle Dynamics in Fluid Flows
- Aeolian processes and effects
- Industrial Gas Emission Control
- Wind and Air Flow Studies
- Fish Ecology and Management Studies
- Data Quality and Management
- Water Quality and Pollution Assessment
- Climate variability and models
- Isotope Analysis in Ecology
- Environmental Toxicology and Ecotoxicology
- Tree-ring climate responses
- Precipitation Measurement and Analysis
Environment and Climate Change Canada
2012-2021
Pacific Northwest National Laboratory
1990
Ministry of the Environment, Conservation and Parks
1980-1984
Campbell Scientific (Canada)
1984
A global assessment of precipitation chemistry and deposition has been carried out under the direction World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) Scientific Advisory Group for Precipitation Chemistry (SAG-PC). The addressed three questions: (1) what do measurements model estimates wet, dry total sulfur, nitrogen, sea salt, base cations, organic acids, acidity, phosphorus show globally regionally? (2) wet major ions changed since 2000 (and, where information data...
Abstract. A parameterization scheme for calculating gaseous dry deposition velocities in air-quality models is revised based on recent study results non-stomatal uptake of O3 and SO2 over 5 different vegetation types. Non-stomatal resistance, which includes in-canopy aerodynamic, soil cuticle resistances, parameterized as a function friction velocity, relative humidity, leaf area index, canopy wetness. resistance other chemical species scaled to those their physical characteristics. Stomatal...
Abstract. We present multi-model global datasets of nitrogen and sulfate deposition covering time periods from 1850 to 2100, calculated within the Atmospheric Chemistry Climate Model Intercomparison Project (ACCMIP). The computed fluxes are compared surface wet ice core measurements. use a new dataset for 2000–2002 based on critical assessment quality existing regional network data. show that day (year 2000 ACCMIP slice), results perform similarly previously published assessments. For this...
Abstract The profound changes in global SO 2 emissions over the last decades have affected atmospheric composition on a regional and scale with large impact air quality, deposition radiative forcing of sulfate aerosols. Reproduction historical pollution levels based aerosol models emission is crucial to prove that such are able predict future scenarios. Here, we analyze consistency trends observations sulfur components precipitation from major networks estimates six different 1990 until...
The nitrogen isotope ratios (δ15N) of atmospheric N species are commonly suggested as indicators emission sources. Therefore, numerous research studies have developed analytical methodologies and characterized primary (gases) secondary products (mostly precipitation aerosols) from various emitters. These previous generally collected either reduced or oxidized forms, sampled them separately prior to determining their δ15N values. Distinctive isotopic signals been reported for emissions...
Reactive nitrogen (Nr) is an essential nutrient to plants and a limiting element for growth in many ecosystems, but it can have harmful effects on ecosystems when excess. Satellite-derived surface observations are used together with dry deposition model estimate the flux of most abundant short-lived species, NH3 NO2, over North America during 2013 warm season. These fluxes demonstrate that contribution dominates NO2 regions (comprising ~85% their sum Canada ~65% U.S.), some regional...
Earth system and environmental impact studies need high quality up-to-date estimates of atmospheric deposition. This study demonstrates the methodological benefits multimodel ensemble measurement-model fusion mapping approaches for deposition focusing on 2010, a year which several were conducted. Global model-only assessment can be further improved by integrating new model-measurement techniques, including expanded capabilities satellite observations composition. We identify research...
Three nitrogen species in air, HNO 3 , particle nitrate (pNO − ), and ammonium (pNH 4 + have been routinely measured for estimating dry deposition the Canadian Air Precipitation Monitoring Network (CAPMoN) U.S. Clean Status Trends (CASNET) several decades. To investigate relative contributions of other to total wet deposition, 14 short‐term field campaigns were conducted between 2001 2005 at eight selected rural sites across eastern Canada. concentrations oxidized (NO y ) major comprising NO...
Abstract. Size-segregated water-soluble inorganic ions, including particulate sulphate (SO42-), nitrate (NO3-), ammonium (NH4+), chloride (Cl-), and base cations (K+, Na+, Mg2+, Ca2+), were measured using a Micro-Orifice Uniform Deposit Impactor (MOUDI) during fourteen short-term field campaigns at eight locations in both polluted remote regions of eastern central Canada. The size distributions SO42- NH4+ unimodal, peaking 0.3–0.6 µm diameter, most the campaigns, although bimodal...
Abstract. Reported sulfur dioxide (SO2) emissions from US and Canadian sources have declined dramatically since the 1990s as a result of emission control measures. Observations Ozone Monitoring Instrument (OMI) on NASA's Aura satellite ground-based in situ measurements are examined to verify whether observed changes SO2 abundance quantitatively consistent with reported emissions. To make this connection, new method link was developed. The is based fitting vertical column densities (VCDs) set...
To quantify differences between dry deposition algorithms commonly used in North America, five models were selected to calculate velocity (Vd) for O3 and SO2 over a temperate mixed forest southern Ontario, Canada, where 5-year flux database had previously been developed. The performed better summer than winter with correlation coefficients hourly Vd measurements being approximately 0.6 0.3, respectively. Differences mean values on the order of factor 2 both winter. All produced lower winter,...
Abstract. SO2 and NOx are precursors to form sulfate, nitrate, ammonium particles in the air, which account for more than 50 % of PM2.5 mass eastern US (Bell et al., 2007) dominant components during many smog events (Dabek-Zlotorzynska 2011). H2SO4 HNO3, formed from oxidation NOx, respectively, main sources acid deposition through wet dry depositions. is also a precursor formation tropospheric O3, an important atmospheric oxidant essential other oxidants, such as OH H2O2. In past 26 years...
With the implementation of Clean Air Act Amendments 1990 in U.S. and similar emission reduction measures Canada, sulfur dioxide (SO2) nitrogen oxides (NOx = NO + NO2) emissions eastern Eastern Canada declined significantly during period 1989–2016. Correspondingly, air quality over region improved tremendously sulfate, nitrate acidity precipitation decreased significantly. In this study, we analyzed measurement data from two national long-term wet deposition networks, National Atmospheric...
We analyzed chemistry trends for 66 Atlantic Canada lakes using data collected from 1983 to 2007, as well 1990 2007 and 2000 the original a further 25 that were later added network. Though receiving lowest acid deposition in eastern North America, region’s waters are seriously affected by rain because of poorly buffering soils bedrock. Earlier work had shown despite large decreases sulfate deposition, lake pH calculated neutralization capacity (ANC c ) not increased they elsewhere America...
Abstract. A statistical method was developed to extract baseline levels of ground level ozone in Canada and the US, quantify temporal changes on annual, seasonal, diurnal decadal scales for period 1997 2006 based ground-level observations from 97 non-urban monitoring sites. Baseline is defined here as measured at a given site absence strong local influences. The quantification involved using Principal Component Analyses (PCA) derive groups commonly-varying sites contiguous regions by season,...
The determination of triple oxygen (δ(18)O and δ(17)O) nitrogen isotopes (δ(15)N) is important when investigating the sources atmospheric paths nitrate nitrite. To fully understand contribution into terrestrial cycle, it crucial to determine δ(15)N values oxidised reduced species in precipitation dry deposition.In an attempt further develop non-biotic methods avoid expensive modifications gas-equilibration system, we have combined modified sample preparation procedures analytical setups used...
We sampled two streams in southwestern Nova Scotia from 1983 to 2004 and one stream 1992 for total organic carbon (TOC) nitrogen (TN) order investigate if changes catchment exports could be determined over the sampling periods, so what were controlling factors. first show that early TOC measurements underestimated concentrations due analytical shortcomings then produce a correction adjust values more accurate levels. Our trend results showed decreased with longest record, 1980 when acid...
We analyzed for trends of acidification related variables from 1983 to 1992 in precipitation concentrations and deposition at six sites surface water 111 located central Ontario eastern Newfoundland. Precipitation showed significantly decreasing H + [Formula: see text] one two Québec (deposition only). For sites, only increasing or stable were observed, these had both concomitant pH (or) acid-neutralizing capacity (ANC). Despite a considerable number lakes showing Québec, ANC also decreased....
Atmospheric sampling was conducted at a rural site near Egbert, about 70 km north of Toronto, Ontario, Canada from March 27 to May 8, 2003 characterize the physical and chemical properties ambient aerosol in real-time. The instrumentation included tapered element oscillating microbalance (TEOM), an ultrafine condensation particle counter (UCPC), scanning mobility sizer (SMPS), aerodynamic (APS), mass spectrometer (AMS), particulate nitrate monitor (R&P 8400N) for measurements. Gas-phase...