The Southeastern Aerosol Research and Characterization Study, Part 3: Continuous Measurements of Fine Particulate Matter Mass and Composition

Edgerton, Eric S.; Hartsell, Benjamin E.; Saylor, Rick; Jansen, J.F.; Hansén, Dan; Hidy, George M.

doi:10.1080/10473289.2006.10464585

Cited by 118 publications

(117 citation statements)

References 21 publications

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“…The latter is consistent with the amplitude of 2.6 µgC/m 3 observed throughout August 2006 at the same location (Geron, 2009). A similar improvement was noted in Yorkville, GA (modeled TC amplitude also dropped from 4.3 to 2.5 µg/m 3 ), where observations also indicate a median daily TC amplitude of 2.6 µg/m 3 (based on 17 days in August 2003 with more than 75% data completeness; Edgerton et al, 2006).…”

Section: Soa Model Enhancementssupporting

confidence: 83%

Incremental testing of the Community Multiscale Air Quality (CMAQ) modeling system version 4.7

et al. 2010

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Abstract. This paper describes the scientific and structural updates to the latest release of the Community Multiscale Air Quality (CMAQ) modeling system version 4.7 (v4.7) and points the reader to additional resources for further details. The model updates were evaluated relative to observations and results from previous model versions in a series of simulations conducted to incrementally assess the effect of each change. The focus of this paper is on five major scientific upgrades: (a) updates to the heterogeneous N 2 O 5 parameterization, (b) improvement in the treatment of secondary organic aerosol (SOA), (c) inclusion of dynamic mass transfer for coarse-mode aerosol, (d) revisions to the cloud model, and (e) new options for the calculation of photolysis rates. Incremental test simulations over the eastern United States during January and August 2006 are evaluated to assess the model response to each scientific improvement, providing explanations of differences in results between v4.7 and previously released CMAQ model versions. Particulate sulfate predictions are improved across all monitoring networks during both seasons due to cloud module updates. Numerous updates to the SOA module improve the simulation of seasonal variability and decrease the bias in organic carbon predictions at urban sites in the winter. Bias in the total mass of fine particulate matter (PM 2.5 ) is dominated by overpredictions of unspeciated PM 2.5 (PM other ) in the winter and by underpredictions of carbon in the summer. The CMAQv4.7 model results show slightly worse performance for ozone predictions.Correspondence to: K. M. Foley (foley.kristen@epa.gov) However, changes to the meteorological inputs are found to have a much greater impact on ozone predictions compared to changes to the CMAQ modules described here. Model updates had little effect on existing biases in wet deposition predictions.

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Section: Soa Model Enhancementssupporting

confidence: 83%

Incremental testing of the Community Multiscale Air Quality (CMAQ) modeling system version 4.7

et al. 2010

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“…Three monitoring sites have subsequently been discontinued: Pensacola (PNS) in 2009, Oak Grove (OAK) in 2010, and Gulfport (GFP) in 2012. Routine measurements at each SEARCH site include continuous trace gases (O 3 , SO 2 , CO, NO, NO 2 , HNO 3 , and total reactive nitrogen [NO y ]), surface meteorology, 24-hr-integrated filter-based PM 2.5 and coarse particle (PM 10-2.5 [PM with an aerodynamic diameter from 2.5 to 10 μm]) mass and composition, as well as semicontinuous PM 2.5 mass and composition (Edgerton et al, 2005(Edgerton et al, , 2006 et al (2003).…”

Section: Measurement Methodsmentioning

confidence: 99%

Recent trends in gas-phase ammonia and PM_2.5 ammonium in the Southeast United States

Saylor

Myles

Sibble

et al. 2014

Journal of the Air & Waste Management Association

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Ammonia measurements from the Southeastern Aerosol Research and Characterization (SEARCH) study network were analyzed for trends over 9 yr (2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012) of observations. Total ammonia concentrations, defined as the sum of gas-phase ammonia and fine particle ammonium, were found to be decreasing by 1-4% yr −1 and were qualitatively consistent with ammonia emission estimates for the SEARCH states of Alabama, Georgia, Mississippi, and Florida. On the other hand, gas-phase ammonia mixing ratios were found to be slightly rising or steady over the region, leading to the observation that the gas-phase fraction of total ammonia has steadily increased over 2004-2012 as a result of declining emissions of the strong acid precursor species sulfur dioxide (SO 2 ) and nitrogen oxides (NO x ) and consequent reduced partitioning of ammonia to the fine particle phase. Because gas-phase ammonia is removed from the atmosphere more rapidly than fine particle ammonium, an increase in the gas-phase fraction of total ammonia may result in shifted deposition patterns as more ammonia is deposited closer to sources rather than transported downwind in fine particles. Additional long-term measurements and modeling studies are needed to determine if similar transitions of total ammonia to the gas phase are occurring outside of the Southeast and to assess if these changes are impacting plants and ecosystems near major ammonia sources. Unusually high ammonia concentrations observed in 2007 in the SEARCH measurements are hypothesized to be linked to emissions from wildfires that were much more prevalent across the Southeast during that year due to elevated temperatures and widespread drought. Although wildfires are currently estimated to be a relatively small fraction (3-10%) of total ammonia emissions in the Southeast, the projected increased incidence of wildfires in this region as a result of global climate change may lead to this source's increased importance over the rest of the 21st century.Implications: Ammonia concentrations from the Southeastern Aerosol Research and Characterization study (SEARCH) network are analyzed over the 9-yr period 2004-2012. Total ammonia (gaseous ammonia + PM 2.5 ammonium) concentrations declined at a rate of 1-4% yr −1 , consistent with U.S. Environmental Protection Agency (EPA) emission estimates for the Southeast United States, but the fraction of ammonia in the gas phase has risen steadily (+1-3% yr −1 ) over the time period. Declining emissions of SO 2 and NO x resulting from imposed air quality regulations have resulted in decreased atmospheric strong acids and less ammonia partitioning to the particle phase, which may impact the amount and overall pattern of ammonia deposition.

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“…In situ measurements of surface NO 2 were made at the Southeastern Aerosol Research and Characterization (SEARCH) network, consisting of 7 sites in the Southeastern United States (Edgerton et al, 2006). We use data from two regionally representative sites: Centreville, in Alabama, and Yorkville, in Georgia measured during 2006-2009.…”

Section: In Situ Surface Measurementsmentioning

confidence: 99%

Evaluation of OMI operational standard NO<sub>2</sub> column retrievals using in situ and surface-based NO<sub>2</sub> observations

et al. 2014

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Abstract. We assess the standard operational nitrogen dioxide (NO 2 ) data product (OMNO2, version 2.1) retrieved from the Ozone Monitoring Instrument (OMI) onboard NASA's Aura satellite using a combination of aircraft and surface in situ measurements as well as ground-based column measurements at several locations and a bottom-up NO x emission inventory over the continental US. Despite considerable sampling differences, NO 2 vertical column densities from OMI are modestly correlated (r = 0.3-0.8) with in situ measurements of tropospheric NO 2 from aircraft, ground-based observations of NO 2 columns from MAX-DOAS and Pandora instruments, in situ surface NO 2 measurements from photolytic converter instruments, and a bottom-up NO x emission inventory. Overall, OMI retrievals tend to be lower in urban regions and higher in remote areas, but generally agree with other measurements to within ± 20 %. No consistent seasonal bias is evident. Contrasting results between different data sets reveal complexities behind NO 2 validation. Since validation data sets are scarce and are limited in space and time, validation of the global product is still limited in scope by spatial and temporal coverage and retrieval conditions. Monthly mean vertical NO 2 profile shapes from the Global Modeling Initiative (GMI) chemistry-transport model (CTM) used in the OMI retrievals are highly consistent with in situ aircraft measurements, but these measured profiles exhibit considerable day-to-day variation, affecting the retrieved daily NO 2 columns by up to 40 %. This assessment of OMI tropospheric NO 2 columns, together with the comparison of OMI-retrieved and model-simulated NO 2 columns, could offer diagnostic evaluation of the model.

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The Southeastern Aerosol Research and Characterization Study, Part 3: Continuous Measurements of Fine Particulate Matter Mass and Composition

Cited by 118 publications

References 21 publications

Incremental testing of the Community Multiscale Air Quality (CMAQ) modeling system version 4.7

Incremental testing of the Community Multiscale Air Quality (CMAQ) modeling system version 4.7

Recent trends in gas-phase ammonia and PM_2.5 ammonium in the Southeast United States

Evaluation of OMI operational standard NO<sub>2</sub> column retrievals using in situ and surface-based NO<sub>2</sub> observations

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The Southeastern Aerosol Research and Characterization Study, Part 3: Continuous Measurements of Fine Particulate Matter Mass and Composition

Cited by 118 publications

References 21 publications

Incremental testing of the Community Multiscale Air Quality (CMAQ) modeling system version 4.7

Incremental testing of the Community Multiscale Air Quality (CMAQ) modeling system version 4.7

Recent trends in gas-phase ammonia and PM2.5 ammonium in the Southeast United States

Evaluation of OMI operational standard NO&lt;sub&gt;2&lt;/sub&gt; column retrievals using in situ and surface-based NO&lt;sub&gt;2&lt;/sub&gt; observations

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Recent trends in gas-phase ammonia and PM_2.5 ammonium in the Southeast United States

Evaluation of OMI operational standard NO<sub>2</sub> column retrievals using in situ and surface-based NO<sub>2</sub> observations