Publications by authors named "Barkley C Sive"

8 Publications

  • Page 1 of 1

A review of measurements of air-surface exchange of reactive nitrogen in natural ecosystems across North America.

Sci Total Environ 2020 Jan 21;698:133975. Epub 2019 Aug 21.

U.S. EPA, Office of Research and Development, Durham, NC, USA.

This review summarizes the state of the science of measurements of dry deposition of reactive nitrogen (Nr) compounds in North America, beginning with current understanding of the importance of dry deposition at the U.S. continental scale followed by a review of micrometeorological flux measurement methods. Measurements of Nr air-surface exchange in natural ecosystems of North America are then summarized, focusing on the U.S. and Canada. Drawing on this synthesis, research needed to address the incompleteness of dry deposition budgets, more fully characterize temporal and geographical variability of fluxes, and better understand air-surface exchange processes is identified. Our assessment points to several data and knowledge gaps that must be addressed to advance dry deposition budgets and air-surface exchange modeling for North American ecosystems. For example, recent studies of particulate (NO) and gaseous (NO, HONO, peroxy nitrates) oxidized N fluxes challenge the fundamental framework of unidirectional flux from the atmosphere to the surface employed in most deposition models. Measurements in forest ecosystems document the importance of in-canopy chemical processes in regulating the net flux between the atmosphere and biosphere, which can result in net loss from the canopy. These results emphasize the need for studies to quantify within- and near-canopy sources and sinks of the full suite of components of the Nr chemical system under study (e.g., NO or HNO-NH-NHNO). With respect to specific ecosystems and geographical locations, additional flux measurements are needed particularly in agricultural regions (NH), coastal zones (NO and organic N), and arid ecosystems and along urban to rural gradients (NO). Measurements that investigate non-stomatal exchange processes (e.g., deposition to wet surfaces) and the biogeochemical drivers of bidirectional exchange (e.g., NH) are considered high priority. Establishment of long-term sites for process level measurements of reactive chemical fluxes should be viewed as a high priority long-term endeavor of the atmospheric chemistry and ecological communities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.scitotenv.2019.133975DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7032654PMC
January 2020

Impact of Front Range sources on reactive nitrogen concentrations and deposition in Rocky Mountain National Park.

PeerJ 2018 15;6:e4759. Epub 2018 May 15.

Department of Atmospheric Science, Colorado State University, Fort Collins, CO, United States of America.

Human influenced atmospheric reactive nitrogen (RN) is impacting ecosystems in Rocky Mountain National Park (ROMO). Due to ROMO's protected status as a Class 1 area, these changes are concerning, and improving our understanding of the contributions of different types of RN and their sources is important for reducing impacts in ROMO. In July-August 2014 the most comprehensive measurements (to date) of RN were made in ROMO during the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ). Measurements included peroxyacetyl nitrate (PAN), C-C alkyl nitrates, and high-time resolution NO, NO, and ammonia. A limited set of measurements was extended through October. Co-located measurements of a suite of volatile organic compounds provide information on source types impacting ROMO. Specifically, we use ethane as a tracer of oil and gas operations and tetrachloroethylene (CCl) as an urban tracer to investigate their relationship with RN species and transport patterns. Results of this analysis suggest elevated RN concentrations are associated with emissions from oil and gas operations, which are frequently co-located with agricultural production and livestock feeding areas in the region, and from urban areas. There also are periods where RN at ROMO is impacted by long-range transport. We present an atmospheric RN budget and a nitrogen deposition budget with dry and wet components. Total deposition for the period (7/1-9/30) was estimated at 1.58 kg N/ha, with 87% from wet deposition during this period of above average precipitation. Ammonium wet deposition was the dominant contributor to total nitrogen deposition followed by nitrate wet deposition and total dry deposition. Ammonia was estimated to be the largest contributor to dry deposition followed by nitric acid and PAN (other species included alkyl nitrates, ammonium and nitrate). All three species are challenging to measure routinely, especially at high time resolution.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7717/peerj.4759DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5958887PMC
May 2018

Extractive FTIR spectroscopy with cryogen-free low-temperature inert preconcentration for autonomous measurements of atmospheric organics: 1: Instrument development and preliminary performance.

Appl Opt 2015 Apr;54(10):2908-21

In collaboration with the Jefferson County Department of Health and the Environmental Protection Agency (EPA), the University of Alabama in Huntsville developed a novel sensor for detecting very low levels of volatile organic compounds (VOCs). This sensor uses a commercial Fourier-transform infrared (FTIR) spectrometer, a commercial long-path IR gas cell, a commercial acoustic Stirling cyrocooler, and a custom cryogen-free cryotrap to improve sensitivity in an autonomous system with on-board quality control and quality assurance. Laboratory and initial field results show this methodology is sensitive to and well-suited for a wide variety of VOC atmospheric research and monitoring applications, including EPA National Air Toxics Trends Stations and the National Core monitoring network.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1364/AO.54.002908DOI Listing
April 2015

Impact of Marcellus Shale natural gas development in southwest Pennsylvania on volatile organic compound emissions and regional air quality.

Environ Sci Technol 2015 Mar 12;49(5):3175-84. Epub 2015 Feb 12.

Natural Resources and Earth System Science Program, University of New Hampshire , Durham, New Hampshire 03824, United States.

The Marcellus Shale is the largest natural gas deposit in the U.S. and rapid development of this resource has raised concerns about regional air pollution. A field campaign was conducted in the southwestern Pennsylvania region of the Marcellus Shale to investigate the impact of unconventional natural gas (UNG) production operations on regional air quality. Whole air samples were collected throughout an 8050 km(2) grid surrounding Pittsburgh and analyzed for methane, carbon dioxide, and C1-C10 volatile organic compounds (VOCs). Elevated mixing ratios of methane and C2-C8 alkanes were observed in areas with the highest density of UNG wells. Source apportionment was used to identify characteristic emission ratios for UNG sources, and results indicated that UNG emissions were responsible for the majority of mixing ratios of C2-C8 alkanes, but accounted for a small proportion of alkene and aromatic compounds. The VOC emissions from UNG operations accounted for 17 ± 19% of the regional kinetic hydroxyl radical reactivity of nonbiogenic VOCs suggesting that natural gas emissions may affect compliance with federal ozone standards. A first approximation of methane emissions from the study area of 10.0 ± 5.2 kg s(-1) provides a baseline for determining the efficacy of regulatory emission control efforts.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/es504315fDOI Listing
March 2015

Phenol groups in northeastern U.S. submicrometer aerosol particles produced from seawater sources.

Environ Sci Technol 2010 Apr;44(7):2542-8

Scripps Institution of Oceanography, University of California San Diego, La Jolla California 92093-0221, USA.

Atmospheric particles collected during the ICARTT 2004 field experiment at ground based sites at Appledore Island (AI), New Hampshire, Chebogue Point (CP), Nova Scotia, and aboard the R/V Ronald Brown (RB) were analyzed using Fourier transform infrared (FTIR) spectroscopy to quantify organic mass (OM) and organic functional groups. Several of these spectra contain a unique absorbance peak at 3500 cm(-1). Laboratory calibrations identify this peak with phenol functional groups. The phenol groups are associated with seawater-derived emissions based on correlations with tracer volatile organic compounds (VOCs) and ions, and potential source contribution function (PSCF) analysis. On the basis of the measured absorptivities, the project average phenol group concentrations are 0.24 +/- 0.18 microg m(-3) (4% of the total OM) at AI, 0.10 +/- 0.6 microg m(-3) (5% of the total OM) at CP, and 0.08 +/- 0.09 microg m(-3) (2% of the total OM) on board the RB, with detection limits typically between 0.06 and 0.11 microg m(-3). The spectra were partitioned into three primary factors using positive matrix factorization (PMF) sufficient to explain more than 95% of the measured OM. The fossil fuel combustion factor contributed 40% (AI), 34% (CP), and 43% (RB) of the total OM; the terrestrial biogenic factor contributed 20% (AI), 30% (CP), and 27% (RB). The seawater-derived factor contributed 40% (AI), 36% (CP) and 29% (RB) of the OM and showed similar correlations to tracers as the phenol group.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/es9032277DOI Listing
April 2010

Air toxic emissions from snowmobiles in Yellowstone National Park.

Environ Sci Technol 2010 Jan;44(1):222-8

Climate Change Research Center, Institute for the Study of Earth, Oceans and Space, University of New Hampshire, Durham, New Hampshire 03824, USA.

A study on emissions associated with oversnow travel in Yellowstone National Park (YNP) was conducted for the time period of February 13-16, 2002 and February 12-16, 2003. Whole air and exhaust samples were characterized for 85 volatile organic compounds using gas chromatography. The toxics including benzene, toluene, ethylbenzene, xylenes (p-, m-, and o-xylene), and n-hexane, which are major components of two-stroke engine exhaust, show large enhancements during sampling periods resulting from increased snowmobile traffic. Evaluation of the photochemical history of air masses sampled in YNP revealed that emissions of these air toxics were (i) recent, (ii) persistent throughout the region, and (iii) consistent with the two-stroke engine exhaust sample fingerprints. The annual fluxes were estimated to be 0.35, 1.12, 0.24, 1.45, and 0.36 Gg yr(-1) for benzene, toluene, ethylbenzene, xylenes, and n-hexane, respectively, from snowmobile usage in YNP. These results are comparable to the flux estimates of 0.23, 0.77, 0.17, and 0.70 Gg yr(-1) for benzene, toluene, ethylbenzene, and xylenes, respectively, that were derived on the basis of (i) actual snowmobile counts in the Park and (ii) our ambient measurements conducted in 2003. Extrapolating these results, annual emissions from snowmobiles in the U.S. appear to be significantly higher than the values from the EPA National Emissions Inventory (1999). Snowmobile emissions represent a significant fraction ( approximately 14-21%) of air toxics with respect to EPA estimates of emissions by nonroad vehicles. Further investigation is warranted to more rigorously quantify the difference between our estimates and emission inventories.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/es9018578DOI Listing
January 2010

Blowing smoke in Yellowstone: air quality impacts of oversnow motorized recreation in the park.

Environ Manage 2008 Feb;41(2):183-99

Department of Geography, The University of Montana, Missoula, MT 59812, USA.

Snowmobile use in Yellowstone National Park has been shown to impact air quality, with implications for the safety and welfare of Park staff and other Park resource values. Localized impacts have been documented at several high-use sites in the Park, but the broader spatial variability of snowmobile emissions and air quality was not understood. Measurements of 87 volatile organic compounds (VOCs) were made for ambient air sampled across the Park and West Yellowstone, Montana, during 2 days of the 2002-2003 winter use season, 1 year before the implementation of a new snowmobile policy. The data were compared with similar data from pristine West Coast sites at similar latitudes. Backward trajectories of local air masses, alkyl nitrate-parent alkane ratios, and atmospheric soundings were used to identify the VOC sources and assess their impact. Different oversnow vehicle types used in the Park were sampled to determine their relative influence on air mass pollutant composition. VOCs were of local origin and demonstrated strong spatiotemporal variability that is primarily influenced by levels of snowmobile traffic on given road segments at different times of day. High levels of snowmobile traffic in and around West Yellowstone produced consistently high levels of benzene, toluene, and carbon monoxide.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00267-007-9036-8DOI Listing
February 2008

Development of a cryogen-free concentration system for measurements of volatile organic compounds.

Anal Chem 2005 Nov;77(21):6989-98

Climate Change Research Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, New Hampshire 03824, USA.

An innovative cryogen-free concentrator system for measurement of atmospheric trace gases at the parts per trillion level has been developed with detection by routinely used gas chromatographic methods. The first-generation system was capable of reaching a trapping temperature of -186 degrees C, while the current version can reach -195 degrees C. A Kleemenko cooler is used to create liquid nitrogen equivalent trapping conditions and eliminate the use of solid absorbents, a potential source of artifacts. The method utilizes dual-stage trapping with individual cold regions. The two stages are cooled to -20 and -175 degrees C for water management and sample enrichment, respectively. Both stages house a Silonite-coated stainless steel sample loop; the second stage loop is filled with 1-mm-diameter glass beads, which provide an inert surface area for analyte concentration. In our application, the complete system employed four channels utilizing two flame ionization detectors, one electron capture detector, and a mass spectrometer. The system was automated for unattended operation and was deployed off the New England east coast on Appledore Island to measure a suite of ambient non-methane hydrocarbons, halocarbons, alkyl nitrates, and oxygenated volatile organic compounds during the International Consortium for Atmospheric Research on Transport and Transformation field campaign in summer 2004. This robust system quantified 98 ambient volatile organic compounds with precisions ranging from 0.3 to 15%.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/ac0506231DOI Listing
November 2005