Duff burning from wildfires in a moist region: different impacts on PM_2.5 and ozone

Wildfires can significantly impact air quality and human health. However, little is known about how different fuel bed components contribute to these impacts. This study investigates the air quality impacts of duff and peat consumption during wildfires in the southeastern United States, with a focus on the differing contributions of fine particulate matter less than 2.5 µm in size (PM2.5) and ozone (O3) to air quality episodes associated with the four largest wildfire events in the region during this century. The emissions of duff burning were estimated based on a field measurement of a 2016 southern Appalachian fire. The emissions from the burning of other fuels were obtained from the Fire INventory from NCAR (FINN). The air quality impacts were simulated using a three-dimensional regional air quality model. The results show the duff burning emitted PM2.5 comparable to the burning of the above-ground fuels. The simulated surface PM2.5 concentrations due to duff burning increased by 61.3 % locally over a region approximately 300 km within the fire site and by 21.3 % and 29.7 % in remote metro Atlanta and Charlotte during the 2016 southern Appalachian fires and by 131.9 % locally and by 17.7 % and 24.8 % in remote metro Orlando and Miami during the 2007 Okefenokee Fire. However, the simulated ozone impacts from the duff burning were negligible due to the small duff emission factors of ozone precursors such as NOx. This study suggests the need to improve the modeling of PM2.5 and the air quality, human health, and climate impacts of wildfires in moist ecosystems by including duff burning in global fire emission inventories.

Rapid Ecological Integrity Assessment Metrics to Restore Wildlife Habitat and Biodiversity for Shortleaf Pine–Oak Ecosystems

Open woodlands dominated by shortleaf pine (Pinus echinata Mill.) and oak are historically an important component of the landscape across the southeastern United States. These ecosystems support numerous wildlife species, many of which have declined in recent years as the amount and condition of their habitat have declined. Land managers and private landowners need guidance on how to efficiently and accurately quantify the condition and wildlife habitat value of the pine stands that they manage. Here we provide a set of rapid assessment metrics, based on NatureServe’s ecological integrity assessment (EIA) method, to (a) identify exemplary tracts that provide the best habitat for key wildlife species, and (b) monitor restoration efforts to assess progress toward the improved quality of existing tracts. To ensure an ecologically appropriate scaling of metrics, we distinguished six types of shortleaf pine–oak woodland: A.—Interior Highlands shortleaf pine–oak (including A.1—shortleaf pine–oak forest and woodlands; A.2—shortleaf pine–bluestem woodlands); B—montane longleaf pine–shortleaf pine woodlands; C—southern Appalachian pine–oak woodlands; D—West Gulf coastal plain shortleaf pine–oak woodlands; and E—southeast coastal plain and Piedmont shortleaf pine–oak woodlands. We relied on a narrative conceptual model and peer review-based indicator selection to identify a core set of 15 stand-level metrics (two were optional). Individual assessment points (thresholds) and ratings (Excellent, Good, Fair, and Poor) were developed that were sensitive to the distinct attributes of each of the five shortleaf pine–oak and Appalachian pine–oak types. Values for the metrics can all be collected using rapid field methods, such as using basal area prisms and ocular (visual) estimates of cover. Protocols for the consistent application of these EIA methods are provided. A case study is presented from the Cherokee National Forest in Tennessee. These methods provide improved and rapid EIA metrics for all shortleaf pine–oak ecosystems in the southeastern US to help guide conservation-minded landowners in assessing the biodiversity and priority wildlife values of shortleaf pine–oak and southern Appalachian pine–oak ecosystems.

914. The Relationship Between Buprenorphine Maintenance Therapy and Hepatitis C Virus Infection, Testing, and Treatment in Southern Appalachian Ohio

Background The hepatitis C virus (HCV) epidemic in the United States is primarily among young people who use drugs (PWUD), especially in rural and Appalachian regions. Buprenorphine maintenance therapy (BMT) may indirectly prevent HCV infection by reducing injection drug use. We aim to assess the relationship between BMT and HCV infection, testing, and treatment among rural PWUD. Methods We conducted a cross-sectional respondent driven sampling survey of 243 PWUD adults in southern Appalachian Ohio from May to November 2019. Participants completed audio computer-assisted self-interview and were tested for HCV antibodies. We defined recent BMT use as self-reported BMT in the past 30 days and prior BMT use as self-reported BMT any time prior to the past 30 days. HCV antibody positive participants were incentivized to receive confirmatory HCV RNA testing. We fit log-binomial regression models to assess the relationship between BMT and HCV infection, testing, and treatment. Results 72% of participants were HCV antibody positive (n=175). 31% (n=54) of antibody positive participants received an RNA test; of those, 96% (n=52) were HCV RNA positive. Compared to participants with no history of BMT, those with prior BMT were more likely to be HCV antibody positive (PR=1.3, 95% CI: 1.1-1.6) and to have been tested for HCV (PR=1.3 95% CI: 1.1-1.5); they were somewhat more likely to have been treated for HCV (PR=1.3 95% CI: 0.5-3.4). Compared to participants with no history of BMT, those reporting recent BMT had similar HCV antibody positivity (PR=1.1 95% CI: 0.9-1.5) but were more likely to have been tested (PR=1.3 95% CI: 1.1-1.6) and possibly more likely to have been treated for HCV (PR=2.0 95% CI: 0.6-5.9). Compared to those with a prior BMT, people with recent BMT use had slightly lower HCV antibody positivity (PR=0.8 95% CI: 0.7-1.1) and possibly higher prevalence of HCV treatment (PR=1.5 95% CI: 0.6-3.8) but had similar prevalence of HCV testing (PR=1.0 95% CI: 0.9-1.2). Conclusion Participants with a recent history of BMT were more likely to have been tested for HCV and possibly to have received prior treatment. Participants with prior BMT were more likely to be antibody positive and to have tested for HCV. Improved coordination between BMT and HCV care may increase HCV treatment among rural PWUD. Disclosures All Authors: No reported disclosures

Supplemental Material: Detrital zircon geothermochronology reveals pre-Alleghanian exhumation of regional Mississippian sediment sources in the southern Appalachian Valley and Ridge Province

<div>Figure 4 is interactive. Hover over each sample set (right) to see stacked on composition-age fields (left) (A) 250–500 Ma and (B) 800– 1200 Ma. Layers may be viewed separately or in combination using the capabilities of the Acrobat (PDF) layering function (click “Layers” icon along vertical bar on left side of window for display of available layers; turn layers on or off by clicking the box to the left of the layer name). Figure 5 is interactive. Hover over the Th/U>75 (black-red) box and Th/U<75 (green) box in the lower part of the figure to view subset KDEs of each sample. Layers may be viewed separately or in combination using the capabilities of the Acrobat (PDF) layering function (click “Layers” icon along vertical bar on left side of window for display of available layers; turn layers on or off by clicking the box to the left of the layer name).<br></div>

Supplemental Material: Detrital zircon geothermochronology reveals pre-Alleghanian exhumation of regional Mississippian sediment sources in the southern Appalachian Valley and Ridge Province

<div>Figure 4 is interactive. Hover over each sample set (right) to see stacked on composition-age fields (left) (A) 250–500 Ma and (B) 800– 1200 Ma. Layers may be viewed separately or in combination using the capabilities of the Acrobat (PDF) layering function (click “Layers” icon along vertical bar on left side of window for display of available layers; turn layers on or off by clicking the box to the left of the layer name). Figure 5 is interactive. Hover over the Th/U>75 (black-red) box and Th/U<75 (green) box in the lower part of the figure to view subset KDEs of each sample. Layers may be viewed separately or in combination using the capabilities of the Acrobat (PDF) layering function (click “Layers” icon along vertical bar on left side of window for display of available layers; turn layers on or off by clicking the box to the left of the layer name).<br></div>