David Risk
Biographic Data
| ID | 6822674 |
|---|---|
| NAME | David Risk |
| GIVEN NAMES | David |
| FAMILY NAME | Risk |
| SIGNATURE | RISK D |
| AFFILIATIONS | St. Francis Xavier University |
| ORCID | 0000-0002-5747-1706 |
| VERIFIED | Yes |
| TOTAL WORKS | 11 |
| TOTAL CITATIONS | 0 |
| AUTHOR COUNT | 11 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 2008 |
| LATEST PUBLICATION YEAR | 2026 |
| H-INDEX | 0 |
Rethinking EPA Method 21 Surface Emissions Monitoring
Municipal solid waste (MSW) landfills are major methane sources, yet regulations still rely on U.S. EPA Method 21 Surface Emissions Monitoring (SEM) or similar protocols developed for industrial leak detection and defined by 30-m traverse spacing and a 500 ppmv action threshold. Despite long use, its probability of detection (POD), minimum detection limit (MDL), and emission-reduction potential at MSW landfills have not been quantitatively charac…
A review of landfill methane emission detection, localization, and quantification systems
We address the need for more accurate and effective monitoring of methane emissions from landfills by reviewing traditional and emerging emissions detection, localization, and quantification field-based technologies. This review explores the advantages and limitations of current and emerging technologies and defines each monitoring technology as a system composed of a platform, sensor hardware, and data post-processing. Mathematical models (e.g.,…
Canada’s landfill methane inventories
We present a measurement-based assessment of methane emissions from 42 landfills across diverse climatic regions in Canada. Our findings reveal that emission rates predicted by the First-Order Decay (FOD) model used by Environment and Climate Change Canada at the visited sites are substantially higher than most measured emission rates, on average by a factor of 3, particularly for cold and arid climates typical of the Canadian prairie provinces (…
A controlled release experiment for investigating methane measurement performance at landfills
We assessed the performance of various methane measurement solutions in landfill applications during November 6, 2023 and November 14, 2023. A measurement solution is defined as a system or market offering that quantifies and/or localizes emissions. Our study involved full-scale multipoint- and area-source (dispersed) controlled releases of methane from the ground surface of a closed 25-ha landfill with collection system and a background emission…
Active face emissions
This study used mobile surveys of 10 Canadian landfills to assess how methane emissions varied across different landfill sources and operational conditions. The studied landfills included 2 closed landfills, 4 open landfills equipped with Gas Collection and Control Systems (GCCS), and 4 open landfills operating without GCCS. We employed the Gaussian dispersion model to estimate emission fluxes using on-site and off-site transect data. We observed…
Methane emission rate estimates of offshore oil platforms in Newfoundland and Labrador, Canada
Methane (CH4) measurements are needed to better understand emissions from oil and gas activities. While many CH4 measurement studies have been done in Canada, they have not yet examined the reported emission intensities of offshore production, including Hibernia, one of the largest offshore oil facilities globally. For this study, a Twin Otter aircraft was equipped with a Picarro G2210-i gas analyzer and an Aventech wind measurement system to mea…
Sociodemographic and Population Exposure to Upstream Oil and Gas Operations in Canada
Canada, as one of the largest oil and gas producer in the world, is responsible for large emissions of methane, a powerful greenhouse gas. At low levels, methane is not a direct threat to human health; however, human health is affected by exposure to pollutants co-emitted with methane. The objectives of this research were to estimate and map pollutants emitted by the oil and gas industry, to assess the demographic of the population exposed to oil…
Soil surface flux measurements are a reliable means for assessing fugitive gas migration across soils and seasons
As oil and gas wells age and the number of wells drilled increases to meet demand, we may see more instances of fugitive soil gas migration (GM) and associated methane (CH4) emissions. Due to the immense spatiotemporal variability of soils and uncertainty in measurement practice, the detection and quantification of GM emissions is a challenge. Two common measurement techniques include the shallow in-soil gas concentration approach and soil surfac…
Active and inactive oil and gas sites contribute to methane emissions in western Saskatchewan, Canada
The oil and gas industry is Canada’s largest contributor to national methane (CH4) emissions. To quantify the input of active and inactive (suspended and abandoned) oil and gas infrastructure to regional CH4 budgets, we conducted truck-based measurements (transect-based and OTM 33A) with a greenhouse gas analyzer, complimented with optical gas imaging at oil-producing sites of Saskatchewan, including understudied regions. We found that inactive s…
Methane emissions from contrasting production regions within Alberta, Canada
Aggressive reductions of oil and gas sector methane, a potent greenhouse gas, have been proposed in Canada. Few large-scale measurement studies have been conducted to confirm a baseline. This study used a vehicle-based gas monitoring system to measure fugitive and vented gas emissions across Lloydminster (heavy oil), Peace River (heavy oil/bitumen), and Medicine Hat (conventional gas) developments in Alberta, Canada. Four gases (CO2, CH4, H2S, C2…
In situ incubations highlight the environmental constraints on soil organic carbon decomposition
We use root exclusion plots, subsurface gas sampling and in situ diffusivity measurements to quantify in situ soil organic carbon (SOC) decomposition dynamics within separate depth-dependent soil pools (0 and 35 cm). We contrast these measurements with observations of temperature–decomposition potentials, generated from laboratory incubations of the same soils at optimal moisture levels and native temperatures. The decomposition–temperature respo…
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In situ incubations highlight the environmental constraints on soil organic carbon decomposition
We use root exclusion plots, subsurface gas sampling and in situ diffusivity measurements to quantify in situ soil organic carbon (SOC) decomposition dynamics within separate depth-dependent soil pools (0 and 35 cm). We contrast these measurements with observations of temperature–decomposition potentials, generated from laboratory incubations of the same soils at optimal moisture levels and native temperatures. The decomposition–temperature respo…
Methane emissions from contrasting production regions within Alberta, Canada
Aggressive reductions of oil and gas sector methane, a potent greenhouse gas, have been proposed in Canada. Few large-scale measurement studies have been conducted to confirm a baseline. This study used a vehicle-based gas monitoring system to measure fugitive and vented gas emissions across Lloydminster (heavy oil), Peace River (heavy oil/bitumen), and Medicine Hat (conventional gas) developments in Alberta, Canada. Four gases (CO2, CH4, H2S, C2…
Soil surface flux measurements are a reliable means for assessing fugitive gas migration across soils and seasons
As oil and gas wells age and the number of wells drilled increases to meet demand, we may see more instances of fugitive soil gas migration (GM) and associated methane (CH4) emissions. Due to the immense spatiotemporal variability of soils and uncertainty in measurement practice, the detection and quantification of GM emissions is a challenge. Two common measurement techniques include the shallow in-soil gas concentration approach and soil surfac…
Active and inactive oil and gas sites contribute to methane emissions in western Saskatchewan, Canada
The oil and gas industry is Canada’s largest contributor to national methane (CH4) emissions. To quantify the input of active and inactive (suspended and abandoned) oil and gas infrastructure to regional CH4 budgets, we conducted truck-based measurements (transect-based and OTM 33A) with a greenhouse gas analyzer, complimented with optical gas imaging at oil-producing sites of Saskatchewan, including understudied regions. We found that inactive s…
Methane emission rate estimates of offshore oil platforms in Newfoundland and Labrador, Canada
Methane (CH4) measurements are needed to better understand emissions from oil and gas activities. While many CH4 measurement studies have been done in Canada, they have not yet examined the reported emission intensities of offshore production, including Hibernia, one of the largest offshore oil facilities globally. For this study, a Twin Otter aircraft was equipped with a Picarro G2210-i gas analyzer and an Aventech wind measurement system to mea…
Sociodemographic and Population Exposure to Upstream Oil and Gas Operations in Canada
Canada, as one of the largest oil and gas producer in the world, is responsible for large emissions of methane, a powerful greenhouse gas. At low levels, methane is not a direct threat to human health; however, human health is affected by exposure to pollutants co-emitted with methane. The objectives of this research were to estimate and map pollutants emitted by the oil and gas industry, to assess the demographic of the population exposed to oil…
Active face emissions
This study used mobile surveys of 10 Canadian landfills to assess how methane emissions varied across different landfill sources and operational conditions. The studied landfills included 2 closed landfills, 4 open landfills equipped with Gas Collection and Control Systems (GCCS), and 4 open landfills operating without GCCS. We employed the Gaussian dispersion model to estimate emission fluxes using on-site and off-site transect data. We observed…
Rethinking EPA Method 21 Surface Emissions Monitoring
Municipal solid waste (MSW) landfills are major methane sources, yet regulations still rely on U.S. EPA Method 21 Surface Emissions Monitoring (SEM) or similar protocols developed for industrial leak detection and defined by 30-m traverse spacing and a 500 ppmv action threshold. Despite long use, its probability of detection (POD), minimum detection limit (MDL), and emission-reduction potential at MSW landfills have not been quantitatively charac…
A review of landfill methane emission detection, localization, and quantification systems
We address the need for more accurate and effective monitoring of methane emissions from landfills by reviewing traditional and emerging emissions detection, localization, and quantification field-based technologies. This review explores the advantages and limitations of current and emerging technologies and defines each monitoring technology as a system composed of a platform, sensor hardware, and data post-processing. Mathematical models (e.g.,…
Canada’s landfill methane inventories
We present a measurement-based assessment of methane emissions from 42 landfills across diverse climatic regions in Canada. Our findings reveal that emission rates predicted by the First-Order Decay (FOD) model used by Environment and Climate Change Canada at the visited sites are substantially higher than most measured emission rates, on average by a factor of 3, particularly for cold and arid climates typical of the Canadian prairie provinces (…
A controlled release experiment for investigating methane measurement performance at landfills
We assessed the performance of various methane measurement solutions in landfill applications during November 6, 2023 and November 14, 2023. A measurement solution is defined as a system or market offering that quantifies and/or localizes emissions. Our study involved full-scale multipoint- and area-source (dispersed) controlled releases of methane from the ground surface of a closed 25-ha landfill with collection system and a background emission…
Methane (10 works) · Greenhouse gas (8 works) · Methane emissions (8 works) · Atmospheric and Environmental Gas Dynamics (7 works) · Environmental Science (6 works) · Chemistry (5 works) · Geology (5 works) · Landfill Environmental Impact Studies (5 works) · Fugitive emissions (4 works) · Municipal Solid Waste Management (4 works)