Mounting evidence from field and laboratory observations coupled with atmospheric model analyses shows that primary combustion emissions of organic compounds dynamically partition between the vapor ...and particulate phases, especially as near-source emissions dilute and cool to ambient conditions. The most recent version of the Community Multiscale Air Quality model version 5.2 (CMAQv5.2) accounts for the semivolatile partitioning and gas-phase aging of these primary organic aerosol (POA) compounds consistent with experimentally derived parameterizations. We also include a new surrogate species, potential secondary organic aerosol from combustion emissions (pcSOA), which provides a representation of the secondary organic aerosol (SOA) from anthropogenic combustion sources that could be missing from current chemical transport model predictions. The reasons for this missing mass likely include the following: (1) unspeciated semivolatile and intermediate volatility organic compound (SVOC and IVOC, respectively) emissions missing from current inventories, (2) multigenerational aging of organic vapor products from known SOA precursors (e.g., toluene, alkanes), (3) underestimation of SOA yields due to vapor wall losses in smog chamber experiments, and (4) reversible organic compounds-water interactions and/or aqueous-phase processing of known organic vapor emissions. CMAQ predicts the spatially averaged contribution of pcSOA to OA surface concentrations in the continental United States to be 38.6 and 23.6 % in the 2011 winter and summer, respectively. Whereas many past modeling studies focused on a particular measurement campaign, season, location, or model configuration, we endeavor to evaluate the model and important uncertain parameters with a comprehensive set of United States-based model runs using multiple horizontal scales (4 and 12 km), gas-phase chemical mechanisms, and seasons and years. The model with representation of semivolatile POA improves predictions of hourly OA observations over the traditional nonvolatile model at sites during field campaigns in southern California (CalNex, May-June 2010), northern California (CARES, June 2010), the southeast US (SOAS, June 2013; SEARCH, January and July, 2011). Model improvements manifest better correlations (e.g., the correlation coefficient at Pasadena at night increases from 0.38 to 0.62) and reductions in underprediction during the photochemically active afternoon period (e.g., bias at Pasadena from -5.62 to -2.42 μg m
). Daily averaged predictions of observations at routine-monitoring networks from simulations over the continental US (CONUS) in 2011 show modest improvement during winter, with mean biases reducing from 1.14 to 0.73μg m
, but less change in the summer when the decreases from POA evaporation were similar to the magnitude of added SOA mass. Because the model-performance improvement realized by including the relatively simple pcSOA approach is similar to that of more-complicated parameterizations of OA formation and aging, we recommend caution when applying these more-complicated approaches as they currently rely on numerous uncertain parameters. The pcSOA parameters optimized for performance at the southern and northern California sites lead to higher OA formation than is observed in the CONUS evaluation. This may be due to any of the following: variations in real pcSOA in different regions or time periods, too-high concentrations of other OA sources in the model that are important over the larger domain, or other model issues such as loss processes. This discrepancy is likely regionally and temporally dependent and driven by interferences from factors like varying emissions and chemical regimes.
Community Multiscale Air Quality (CMAQ) model simulations utilizing the traditional organic aerosol (OA) treatment (CMAQ-AE6) and a volatility basis set (VBS) treatment for OA (CMAQ-VBS) were ...evaluated against measurements collected at routine monitoring networks (Chemical Speciation Network (CSN) and Interagency Monitoring of Protected Visual Environments (IMPROVE)) and those collected during the 2010 California at the Nexus of Air Quality and Climate Change (CalNex) field campaign to examine important sources of OA in southern California. Traditionally, CMAQ treats primary organic aerosol (POA) as nonvolatile and uses a two-product framework to represent secondary organic aerosol (SOA) formation. CMAQ-VBS instead treats POA as semivolatile and lumps OA using volatility bins spaced an order of magnitude apart. The CMAQ-VBS approach underpredicted organic carbon (OC) at IMPROVE and CSN sites to a greater degree than CMAQ-AE6 due to the semivolatile POA treatment. However, comparisons to aerosol mass spectrometer (AMS) measurements collected at Pasadena, CA, indicated that CMAQ-VBS better represented the diurnal profile and primary/secondary split of OA. CMAQ-VBS SOA underpredicted the average measured AMS oxygenated organic aerosol (OOA, a surrogate for SOA) concentration by a factor of 5.2, representing a considerable improvement to CMAQ-AE6 SOA predictions (factor of 24 lower than AMS). We use two new methods, one based on species ratios (SOA/ΔCO and SOA/Ox) and another on a simplified SOA parameterization, to apportion the SOA underprediction for CMAQ-VBS to slow photochemical oxidation (estimated as 1.5 × lower than observed at Pasadena using −log(NOx : NOy)), low intrinsic SOA formation efficiency (low by 1.6 to 2 × for Pasadena), and low emissions or excessive dispersion for the Pasadena site (estimated to be 1.6 to 2.3 × too low/excessive). The first and third factors are common to CMAQ-AE6, while the intrinsic SOA formation efficiency for that model is estimated to be too low by about 7 × . From source-apportioned model results, we found most of the CMAQ-VBS modeled POA at the Pasadena CalNex site was attributable to meat cooking emissions (48 %, consistent with a substantial fraction of cooking OA in the observations). This is compared to 18 % from gasoline vehicle emissions, 13 % from biomass burning (in the form of residential wood combustion), and 8 % from diesel vehicle emissions. All "other" inventoried emission sources (e.g., industrial, point, and area sources) comprised the final 13 %. The CMAQ-VBS semivolatile POA treatment underpredicted AMS hydrocarbon-like OA (HOA) + cooking-influenced OA (CIOA) at Pasadena by a factor of 1.8 compared to a factor of 1.4 overprediction of POA in CMAQ-AE6, but it did capture the AMS diurnal profile of HOA and CIOA well, with the exception of the midday peak. Overall, the CMAQ-VBS with its semivolatile treatment of POA, SOA from intermediate volatility organic compounds (IVOCs), and aging of SOA improves SOA model performance (though SOA formation efficiency is still 1.6–2 × too low). However, continued efforts are needed to better understand assumptions in the parameterization (e.g., SOA aging) and provide additional certainty to how best to apply existing emission inventories in a framework that treats POA as semivolatile, which currently degrades existing model performance at routine monitoring networks. The VBS and other approaches (e.g., AE6) require additional work to appropriately incorporate IVOC emissions and subsequent SOA formation.
Aircraft measurements made downwind from specific coal fired power plants during the 2013 Southeast Nexus field campaign provide a unique opportunity to evaluate single source photochemical model ...predictions of both O3 and secondary PM2.5 species. The model did well at predicting downwind plume placement. The model shows similar patterns of an increasing fraction of PM2.5 sulfate ion to the sum of SO2 and PM2.5 sulfate ion by distance from the source compared with ambient based estimates. The model was less consistent in capturing downwind ambient based trends in conversion of NO X to NO Y from these sources. Source sensitivity approaches capture near-source O3 titration by fresh NO emissions, in particular subgrid plume treatment. However, capturing this near-source chemical feature did not translate into better downwind peak estimates of single source O3 impacts. The model estimated O3 production from these sources but often was lower than ambient based source production. The downwind transect ambient measurements, in particular secondary PM2.5 and O3, have some level of contribution from other sources which makes direct comparison with model source contribution challenging. Model source attribution results suggest contribution to secondary pollutants from multiple sources even where primary pollutants indicate the presence of a single source.
Efforts using the Community Multiscale Air Quality (CMAQ) model to investigate the impacts of aircraft emissions from the Hartsfield-Jackson Atlanta International Airport have previously shown ...aircraft emissions increased total daily PM2.5 concentrations by up to 9.4% (0.94 μg m−3) with overall impacts varying by modeled grid resolution. However, those results also indicated that secondary organic aerosol (SOA) concentrations in the airport grid cell were reduced due to aircraft emissions at coarser grid resolutions (36-km and 12-km) but not at a finer resolution (4-km). To investigate this anomaly, this study instruments the CMAQ model with process analysis, an advanced diagnostic modeling tool, and focuses on changes to SOA concentrations due to aircraft emissions in the grid cells containing the Atlanta airport at grid resolutions of 36-km, 12-km, and 4-km. Model results indicated aircraft emissions reduced hourly anthropogenic and biogenic SOA concentrations at the 36-km and 12-km grid resolutions by up to 6.2% (0.052 μg m−3) by removing nitrate, hydroxyl, and hydroperoxy radicals through chemistry. At the 4-km resolution, however, hourly modeled SOA concentrations increased (primarily due to changes in biogenic SOA) by up to 11.5% (0.081 μg m−3) due to primary organic aerosol emissions from aircraft, with the additional organic mass shifting partitioning of SOA semi-volatile gas phase species into the particle phase.
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•Impacts of aircraft LTO emissions on SOA modeled at the Atlanta Airport in CMAQ.•Aircraft emissions reduced SOA at 36 and 12-km (by ∼6%), but enhanced at 4-km (by ∼12%).•Process analysis used to determine processes responsible for changes in SOA.•At coarser resolutions, chemistry of free radicals with aircraft NOx emissions reduced SOA.•At the finer resolution, aircraft emissions interacting with biogenic SOA precursors enhanced SOA.
Isolated nodal failure (INF) without synchronous local or distant failure is an uncommon occurrence after stereotactic body radiation therapy (SBRT) for lung cancer. Here we review the natural ...history and patterns of failure after post-SBRT INF with or without salvage mediastinal radiotherapy (SvRT).
Patients treated with SBRT for non–small cell lung cancer with definitive intent were identified. Patients who experienced hilar or mediastinal INF without synchronous distant, lobar, or local failure were included and grouped according to the use of SvRT. The rates of subsequent locoregional control, distant metastases, progression-free survival (PFS), and overall survival were assessed.
Of 797 patients treated with definitive SBRT, 24 (3%) experienced INF and 15 (63%) received SvRT. The most common SvRT regimen (53%) was 45 Gy in 15 fractions. The median follow-up after INF was 11.3 months for survivors. There were no grade 3 or higher toxicities after SvRT. The 1-year Kaplan-Meier PFS and overall survival estimates were 33% and 56% for patients not receiving radiotherapy and 75% and 73% with SvRT. After SvRT, the rate of locoregional control at 1 year was 84.4%. Crude rates of distant failure were 20.0% with SvRT and 22.2% with no radiotherapy. Of the 13 deaths observed, five (38%) were related to distant progression of lung cancer, four (31%) to comorbidities, three (23%) to mediastinal progression, and one (8%) to an unknown cause.
INF is uncommon after SBRT. Despite the significant comorbidities of this population, intrathoracic progression remains a contributor to morbidity and mortality. SVRT for INF is well tolerated and may improve PFS.
To determine the patterns of adjuvant chemoradiotherapy use in elderly patients treated with definitive surgical resection for squamous cell carcinoma of the head and neck with extracapsular ...extension (ECE) or positive margins and determine whether an association with overall survival (OS) exists with adjuvant concurrent chemoradiotherapy (CRT).
The National Cancer Database was queried to identify patients with SCC of the oral cavity, oropharynx, larynx, and hypopharynx who were treated with primary definitive surgery and adjuvant radiation therapy between 2004 and 2012. For elderly patients (aged >70 years) with pathology revealing ECE or positive margin, the benefit of concurrent chemotherapy was explored using multivariable Cox proportional hazards modeling.
A total of 7349 patients were identified meeting study criteria, of whom 1187 were elderly (aged >70 years) with a median follow-up of 30.6 months. Of these elderly patients, 445 had ECE or positive margin and represent the study population, of whom 187 (42%) received CRT. Delivery of CRT in this cohort increased over the study period, and intensity modulated radiation therapy was associated with increased use of CRT (odds ratio 2.07; P=.004). Increasing age was associated with reduced use of CRT (odds ratio 0.88; P<.001). Chemoradiotherapy was associated with a significant improvement in OS on multivariable analysis (hazard ratio 0.74; P=.04) and a trend toward significance on inverse propensity score analysis (hazard ratio 0.78; P=.051). Three-year OS was 53.8% in the CRT group, compared with 44.6% in the adjuvant radiation therapy-alone patients.
The use of adjuvant CRT is increasing among elderly patients with resected squamous cell carcinoma of the head and neck exhibiting ECE or positive margins. Chemoradiotherapy was associated with an improvement in OS on multivariable analysis but not propensity-weighted analysis. Among fit elderly patients with ECE or positive margins after definitive surgical resection, concurrent chemotherapy can be carefully considered.
Patient experience metrics are gaining prominence in health care. We introduce the CAPABLE survey to assess postoperative experiences of Mohs surgery patients.
We sought to determine whether CAPABLE ...scores aligned with overall patient satisfaction in Mohs surgery.
This was a cross-sectional, survey-based study of patients presenting for their first postoperative visit after Mohs surgery. The CAPABLE survey included questions on postoperative instructions, activity limitations, pain control, provider accessibility, and bleeding, followed by 2 overall satisfaction questions taken from the Outpatient and Ambulatory Surgery Consumer Assessment of Healthcare Providers and Systems survey. The pilot study took place at the University of Texas Dell Medical School (DMS), followed by a validation study ( n = 206) at DMS and Oregon Health and Science University (OHSU). We assessed for correlations between CAPABLE scores and overall satisfaction.
In the pilot study ( n = 137), overall CAPABLE scores and scores of individual CAPABLE components correlated positively with overall satisfaction.In the multisite validation study ( n = 206) spanning DMS and OHSU, CAPABLE scores correlated positively with overall satisfaction.
The CAPABLE survey is a concise tool for assessing specific, actionable components of the postoperative patient experience in Mohs surgery, while correlating with overall patient satisfaction.
Recently, the safety of lidocaine plus epinephrine use in outpatient surgery has come under scrutiny despite its long history of use in outpatient dermatologic procedures and surgeries.
To assess the ...frequency of crash cart and other emergency interventions during Mohs micrographic surgery when lidocaine plus epinephrine is used as a local anesthetic and evaluate patient comorbidities associated with these events.
A retrospective chart review was conducted in an outpatient Mohs micrographic surgery clinic.
One thousand one hundred twenty-seven Mohs cases were reviewed from the period of March 2015 to June 2016 with 864 meeting the inclusion criteria of patient weight, medical history, and amount of lidocaine administered recorded. No adverse events requiring emergency intervention with a crash cart or transfer to the emergency department occurred despite a patient population with advanced age and a wide range of comorbidities.
No serious adverse events requiring emergency intervention were associated with lidocaine with epinephrine doses administered below the Food and Drug Administration recommended maximum. The authors did not find evidence from this study or after a literature search to support the requirement for a crash cart and other emergency equipment to be present during procedures.
Although satellite‐based variables have for long been expected to be key components to a unified and global biodiversity monitoring strategy, a definitive and agreed list of these variables still ...remains elusive. The growth of interest in biodiversity variables observable from space has been partly underpinned by the development of the essential biodiversity variable (EBV) framework by the Group on Earth Observations – Biodiversity Observation Network, which itself was guided by the process of identifying essential climate variables. This contribution aims to advance the development of a global biodiversity monitoring strategy by updating the previously published definition of EBV, providing a definition of satellite remote sensing (SRS) EBVs and introducing a set of principles that are believed to be necessary if ecologists and space agencies are to agree on a list of EBVs that can be routinely monitored from space. Progress toward the identification of SRS‐EBVs will require a clear understanding of what makes a biodiversity variable essential, as well as agreement on who the users of the SRS‐EBVs are. Technological and algorithmic developments are rapidly expanding the set of opportunities for SRS in monitoring biodiversity, and so the list of SRS‐EBVs is likely to evolve over time. This means that a clear and common platform for data providers, ecologists, environmental managers, policy makers and remote sensing experts to interact and share ideas needs to be identified to support long‐term coordinated actions.
This contribution introduces a set of definitions and principles that are believed to be necessary if ecologists and space agencies are to agree on a list of essential biodiversity variables that can be routinely monitored from space. In particular, it argues that progress toward the identification of satellite remote sensing EBVs (SRS‐EBVs) will require a clear understanding of what makes a biodiversity variable essential, as well as agreement on who the users of the SRS‐EBVs are.
Objective
To investigate the association between tumor volume and locoregional failure (LRF) after concurrent chemoradiation (CCRT) for locally advanced larynx cancer (LC).
Methods
This is a ...retrospective cohort study from 2009 to 2014 identified from an institutional review board–approved registry. Fifty‐nine of 68 patients with locally advanced larynx cancer treated with definitive CCRT who had available imaging for review were identified. The main endpoint to be assessed was the association between gross tumor volumes (GTV; T = total, P = primary, N = nodal) and LRF. Receiver operative characteristic (ROC) curves were used to investigate diagnostic accuracy.
Results
Twenty LRFs were observed, resulting in a 2‐year LRF rate of 39% (95% CI, 23–52%). On UVA, the GTV‐T (P = .01), GTV‐P (P = .05), and GTV‐N (P = .04) were statistically significant predictors of LRF. Furthermore, age, smoking status, N‐stage, larynx subsite, and tracheostomy/feeding tube dependence were potentially associated with LRF (P < .3), whereas T‐stage (T3–4 vs. T2) was not (HR 1.05, 95% CI, 0.38–2.91, P = .92). In the multivariable model, GTV‐P (HR 1.022, 95% CI, 0.999–1.046, P = .07) and GTV‐N (HR 1.053, 95% CI, 1.0004–1.108, P = .05) were the two most impactful covariates on the model's R2. ROC analysis suggested an optimal cut point of 12 cc in the GTV‐T. The 2‐year LRF for GTV‐T > 12 cc was 64.2% and ≤ 12 cc was 16.4%, P = .006.
Conclusion
GTV is associated with LRF after definitive CCRT for LC. Patients with bulky primary and/or nodal tumors may be better served with upfront surgical resection regardless of T‐stage. Further investigation into the safety of larynx preservation for low‐volume T4 tumors can be considered.
Level of Evidence
4 Laryngoscope, 130:2372–2377, 2020
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