Objectives/Hypothesis
Create a competency‐based assessment tool for pediatric tracheotomy.
Study Design
Blinded, modified, Delphi consensus process.
Methods
Using the REDCap database, a list of 31 ...potential items was circulated to 65 expert surgeons who perform pediatric tracheotomy. In the first round, items were rated as “keep” or “remove,” and comments were incorporated. In the second round, experts were asked to rate the importance of each item on a seven‐point Likert scale. Consensus criteria were determined a priori with a goal of 7 to 25 final items.
Results
The first round achieved a response rate of 39/65 (60.0%), and returned questionnaires were 99.5% complete. All items were rated as “keep,” and 137 comments were incorporated. In the second round, 30 task‐specific and seven previously validated global rating items were distributed, and the response rate was 44/65 (67.7%), with returned questionnaires being 99.3% complete. Of the Task‐Specific Items, 13 reached consensus, 10 were near consensus, and 7 did not achieve consensus. For the 7 previously validated global rating items, 5 reached consensus and two were near consensus.
Conclusions
It is feasible to reach consensus on the important steps involved in pediatric tracheotomy using a modified Delphi consensus process. These items can now be considered to create a competency‐based assessment tool for pediatric tracheotomy. Such a tool will hopefully allow trainees to focus on the important aspects of this procedure and help teaching programs standardize how they evaluate trainees during this procedure.
Level of Evidence
5 Laryngoscope, 130:2700–2707, 2020
Ground-level ozone is a criteria air pollutant which can be transported into an area or produced locally through photochemical reactions between oxides of nitrogen (NOx) and volatile organic ...compounds (VOCs) in the presence of sunlight. For an ozone nonattainment area, it is critically essential to know the sources of the observed ozone before a strategic implementation plan can be established for effective reduction of ozone pollution. In this study, source apportionment simulations of ground-level ozone were performed for the Beaumont-Port Arthur (BPA) Area in Southeast Texas employing CAMx (Comprehensive Air Quality Model with Extensions) through its two built-in tools, i.e., OSAT (Ozone Source Apportionment Technology) and APCA (Anthropogenic Precursor Culpability Assessment), involving the 2012 Ozone Episode developed by TCEQ (Texas Commission on Environmental Quality). The OSAT results have indicated that local emission sources play a major role (82%) in the observed local high ozone events in the BPA area; in the meantime, 14% and 4% of the observed ozone have been identified to have transported into the area from the Southwest Louisiana and Gulf of Mexico, respectively. The APCA results have indicated that the Elevated Point, On-road and Low Point emissions are three major anthropogenic sources contributed to the BPA ozone productions with 60%, 19.5% and 19.5%, respectively. The simulation results provide needed information for the development of an implementation plan for effective reduction of ozone pollution in an ozone nonattainment area.
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•CAMx simulation on June 2012 Ozone Episode over the Southeast Texas of USA were performed.•Both ozone source apportionment methods, OSAT and APCA, were employed with CAMx modeling and simulation.•Formation process and sources of ozone were examined by source apportionment technologies.•Contributions of different spatial regions and source categories on ozone pollution in the BPA area were characterized.
The changing emissions and climate have largely influenced the contribution of different sources on surface ozone, while the relations between the emissions, meteorological conditions and ozone ...sources are highly uncertain. In this study we modeled the sources of surface ozone in central Europe in the summer (June–July–August) of 2018, one of the warmest summers in Europe, with the regional chemical transport model CAMx and its source apportionment tool OSAT. Additional simulations with the anthropogenic emissions in 2000 were performed as high-emission scenarios to investigate the effects of reduced emissions on ozone sources, and a specific analysis on the coupled effects from meteorology was conducted based on measurements and backward trajectory calculations at three Swiss sites. The model results indicate that the highest contribution to summer afternoon surface ozone in Europe in 2018 comes from the boundary import (65%), followed by off-road traffic (11%) and road traffic (8%). Compared to the case using 2000 emissions, the lower emissions in 2018 lead to lower ozone in most of the areas in Europe except for some urban areas and shipping routes, and the highest decrease is from the road traffic for both the whole domain and the Swiss sites. The backward trajectory analysis at Swiss sites in 2000 (base year), 2003 (the warmest year) and 2018 (the 3rd warmest year) show that 2018 is the year with the highest fraction of air mass from the high ozone areas (from east in southern Switzerland and from north in northern Switzerland). The results indicate that the reduced anthropogenic emissions are the main reason responsible for the reduced high level ozone in the hot summer in central Europe.
•Sources of ozone in central Europe in summer 2018 are modeled by CAMx-OSAT.•Effects of reduced emissions since 2000 and meteorology on ozone are investigated.•Meteorological conditions in 2018 bring the highest air mass from high ozone areas.•Reduced anthropogenic emissions are reason for the not-so-high ozone in hot summer.•The reduced emissions from road traffic contribute most to the decrease of ozone.
Vegetation is the leading emitter of volatile organic compounds (VOC), a key ingredient for ozone formation. The contribution of biogenic VOC (BVOC) emissions to regional ozone formation needs better ...quantification so that air quality regulators can effectively design emission control strategies. One of the key uncertainties for modeling BVOC emissions comes from the estimation of photosynthetically active radiation (PAR) reaching canopy. Satellite insolation retrieval data provide an alternative to prognostic meteorological models for representing the spatial and temporal variations of PAR. In this study, biogenic emission estimates generated with the MEGAN and BEIS biogenic emissions models using satellite or prognostic PAR are used to examine the contribution of BVOC to ozone in the United States. The Comprehensive Air Quality Model with Extensions (CAMx) is applied with Ozone Source Apportionment Technology (OSAT) and brute force zero-out sensitivity runs to quantify the biogenic contributions to ozone formation during May through September 2011. The satellite PAR retrievals are on average lower than modeled PAR and exhibit better agreement with SCAN and SURFRAD network measurements. Using satellite retrievals instead of modeled PAR reduces BEIS and MEGAN estimates of isoprene by an average of 3%–4% and 9%–12%, respectively. The simulations still overestimate observed ground-level isoprene concentrations by a factor of 1.1 for BEIS and 2.6 for MEGAN. The spatial pattern of biogenic ozone contribution diagnosed from OSAT differs from the brute force zero-out sensitivity results, with the former more smoothly distributed and the latter exhibiting peak impacts near metropolitan regions with intense anthropogenic NOx emissions. OSAT tends to apportion less ozone to biogenics as BVOC emissions increase, since that shifts marginal ozone formation toward more NOx-limited conditions. By contrast, zero-out source apportionment of ozone to biogenics increases with BVOC emissions. OSAT simulations with BEIS show that BVOCs typically contribute 10–19% to regional ozone concentrations at nonattainment receptor sites during episode days.
•Isoprene emission estimates are compared between two biogenic models.•New GOES satellite retrievals for insolation are introduced.•Satellite retrievals of clouds slightly reduce insolation and emission estimates.•Zero-out and OSAT differ in their source apportionments of ozone.
As one of the most notorious atmospheric pollutants, NOx not only promotes the formation of ozone but also has adverse health effects on humans. It is therefore of great importance to study the ...sources of NOx and its effects on human health. The Comprehensive Air Quality Model (CAMx) modeling system and ozone source apportionment technology (OSAT) were used to study the contribution of NOx from different emission sources over southern China. The results indicate that heavy duty diesel vehicles (HDDVs) and industrial point sources are the two major local NOx sources, accounting for 30.8% and 18.5% of local NOx sources, respectively. In Hong Kong, marine emissions contributed around 43.4% of local NOx in 2011. Regional transport is another important source of this pollutant, especially in February and November, and it can contribute over 30% of ambient NOx on average. Power plant point emission is an significant regional source in Zhuhai, Zhongshan and Foshan. The total emission sources are estimated to cause 2119 (0–4405) respiratory deaths and 991 (0–2281) lung cancer deaths due to long-term exposure to NOx in the Pearl River Delta region. Our results suggest that local governments should combine their efforts and vigorously promote further reduction of NOx emissions, especially for those sources that make a substantial contribution to NOx emissions and affect human health: HDDV, LDGV, industrial point sources and marine sources.
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•WRF-CAMx modeling system with OSAT was used to study the source of NOx over Pearl River Delta region in China.•The results indicated that local emission and regional transportation are important contributors for NOx in this region.•Heavy duty diesel vehicle, marine emission and industrial point source are three important contribution sectors.•Long-term exposure to NOx is estimated to cause 2119 respiratory deaths and 991 lung cancer deaths in PRD during 2011.
Result indicated that heavy duty diesel vehicle and industrial point source make a substantial contribution to ambient NOx concentration in this region.
It is well‐known that ground‐level ozone is not just a local or regional air quality problem; emission sources from super‐regional (sources outside the PRD region) scales are known to contribute ...significantly to local ozone concentrations. However, source apportionment studies differentiating the relative contributions of local, regional, and super‐regional ozone precursors are still limited. In this paper, using the Pearl River Delta (PRD) as an example, we have conducted a detailed apportionment (by source categories and by source regions) study of surface ozone using photochemical model source apportionment tools. Our results show that, while the super‐regional contribution is dominant under mean ozone conditions, elevated local and regional sources are the causative factor for the formation of high ozone episodes. In particular, the local and PRD regional contributions increase from about 30% during non‐episode days to about 50% during high ozone episode days in the autumn (November 2006) and even up to about 70% during high ozone episodes in the summer (July 2006). These results suggest that local and regional controls of ozone precursors are still very important for ozone reduction, particularly for episodic events. Furthermore, our results show that mobile emission is by far the highest contributing source category to ozone levels in the PRD for episodic ozone events. Moreover, we find substantial seasonal variations in the way ozone precursors from neighboring areas affect ozone levels in any particular city, suggesting that regional collaborations are important for developing effective long‐term strategies to reduce ozone over the PRD region.
Key Points
Super‐regional contribution is dominant during non‐episode days
Local and regional sources become larger and are the main cause of ozone episodes
Mobile source is the dominant source category for ozone formation in the PRD
Multiple approaches to characterize lateral boundary contributions to photochemical model predicted ozone (O3) and particulate matter less than 2.5 microns in diameter (PM2.5) are available in the ...Comprehensive Air quality Model with extensions (CAMx). Here, three approaches are used for O3: (1) a comprehensive source apportionment scheme for chemical boundary conditions and emissions (OSAT), (2) chemically reactive tracers (RTRAC), and (3) chemically inert tracers. Two approaches are used for PM2.5: (1) particulate source apportionment (PSAT) and (2) chemically inert tracers. The inert tracer approach resulted in higher O3 lateral boundary contribution estimates because the method does not account for any O3 destruction reactions. OSAT and RTRAC estimate generally similar monthly average contributions during the warmer months although RTRAC estimates higher urban area contribution during the cold months because this RTRAC implementation did not treat O3 titration by NO. Accurate representation of lateral boundary O3 impacts must include appropriate accounting for O3 destruction reactions. OSAT and RTRAC were configured to estimate the contribution to modeled O3 from each of the four lateral faces of the model domain. RTRAC was configured to further stratify the western and northern boundaries by groups of vertical layers. The RTRAC approach showed that the largest O3 contributions to the continental U.S. are from the mid-troposphere, with less contribution from the upper troposphere/lower stratosphere. Inert tracers compared more closely to reactive tracers on average for PM2.5 compared to O3. This close agreement for PM2.5 indicates most of the lateral boundary contribution is from PM2.5 rather than precursor inflow. A strong relationship exists between model predicted PM2.5 boundary contribution and model overestimates of nitrate and organic carbon at IMPROVE monitor locations suggesting global model estimates of these species were overestimated at some places and times.
•Photochemical model source apportionment provides credible boundary contributions.•Inert tracer method overestimates ozone lateral boundary inflow contribution.•Spring intermountain west ozone contribution largely from west/north mid/upper-troposphere.
Evaluating long-term air quality trends can demonstrate effectiveness of control strategies and guide future air quality management planning. Observations have shown that ozone (O3) and fine ...particulate matter (PM2.5) in the US have declined since as early as 1980 in some areas. But observation trends alone cannot separate effects of changes in local and global emissions to US air quality which are important to air quality planners. This study uses a regional model (CAMx) nested within a global model (GEOS-Chem) to characterize regional changes in O3 and PM2.5 due to the intercontinental transport and local/regional emissions representing six modeling years within five decades (1970–2020). We use the CAMx Source Apportionment Technology (OSAT/PSAT) to estimate contributions from 6 source sectors in 7 source regions plus 6 other groups for a total of 48 tagged contributions. On-road mobile sources consistently make the largest U.S. anthropogenic emissions contribution to O3 in all cities examined even though they decline substantially from 1970 to 2005 and also from 2005 to 2020. Off-road mobile source contributions increase from 1970 to 2005 and then decrease after 2005 in all of the cities. The boundary conditions, mostly from intercontinental transport, contribute more than 20 ppb to high maximum daily 8-h average (MDA8) O3 for all six years. We found that lowering NOx emissions raises O3 formation efficiency (OFE) across all emission categories which will limit potential O3 benefits of local NOx strategies in the near future. PM2.5 benefited from adoption of control devices between 1970 and 1980 and has continued to decline through 2005 and expected to decline further by 2020. Area sources such as residential, commercial and fugitive dust emissions stand out as making large contributions to PM2.5 that are not declining. Inter-regional transport is less important in 2020 than 1990 for both pollutants.
•U.S. emissions contributions to ozone and PM2.5 have reduced over five decades.•On-road mobile and EGU contributions have declined substantially since 1970.•Contributions of non-EGU and area sources are declining less since 2005.•Ozone production efficiency rises from 2000 onwards as NOx emissions are reduced.•Inter-regional transport is becoming less important in contrast to background ozone.
Emission source contributions of tropospheric ozone (O3) were comprehensively investigated by using the higher‐order decoupled direct method (HDDM) for sensitivity analysis and the ozone source ...apportionment technology (OSAT) for mass balance analysis in the comprehensive air‐quality model with extensions (CAMx). The response of O3 to emissions reductions at various levels in mainland China, Korea, and Japan were estimated and compared with results calculated by the brute force method (BFM) where one model parameter is varied at a time. Emissions were assessed at three receptor sites in Japan that experienced severe pollution events in May 2009. For emissions from China, HDDM assessed O3 response with a bias of only up to 3 ppbv (a relative error of 4.5%) even for a 50% reduction but failed to assess a more extreme reduction. OSAT was reasonably accurate at 100% reduction, with a −4 ppbv (−7%) bias, but was less accurate at moderate ranges of reduction (∼50–70%). For emissions from Korea and Japan, HDDM captured the nonlinear response at all receptor sites and at all reduction levels to within 1% in all but one case; however, the bias of OSAT increased with the increasing reduction of emissions. One possible reason for this is that OSAT does not account for NO titration. To address this, a term for potential ozone (PO; O3 and NO2 together) was introduced. Using of PO instead of O3 improved the performance of OSAT, especially for emissions reductions from Korea and Japan. The proposed approach with PO refined the OSAT results and did not degrade HDDM performance.
Key Points
Sensitivity analysis and mass balance analysis were comprehensively compared
Exclusion of NO titration was identified as limitation in mass balance analysis
Potential ozone (PO = O3+NO2) effectively addressed the limitation
Objectives/Hypothesis
Create a competency‐based assessment tool for pediatric esophagoscopy with foreign body removal.
Study Design
Blinded modified Delphi consensus process.
Setting
Tertiary care ...center.
Methods
A list of 25 potential items was sent via the Research Electronic Data Capture database to 66 expert surgeons who perform pediatric esophagoscopy. In the first round, items were rated as “keep” or “remove” and comments were incorporated. In the second round, experts rated the importance of each item on a seven‐point Likert scale. Consensus was determined with a goal of 7 to 25 final items.
Results
The response rate was 38/64 (59.4%) in the first round and returned questionnaires were 100% complete. Experts wanted to “keep” all items and 172 comments were incorporated. Twenty‐four task‐specific and 7 previously‐validated global rating items were distributed in the second round, and the response rate was 53/64 (82.8%) with questionnaires returned 97.5% complete. Of the task‐specific items, 9 reached consensus, 7 were near consensus, and 8 did not achieve consensus. For global rating items that were previously validated, 6 reached consensus and 1 was near consensus.
Conclusions
It is possible to reach consensus about the important steps involved in rigid esophagoscopy with foreign body removal using a modified Delphi consensus technique. These items can now be considered when evaluating trainees during this procedure. This tool may allow trainees to focus on important steps of the procedure and help training programs standardize how trainees are evaluated.
Level of Evidence
5. Laryngoscope, 131:1168–1174, 2021
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