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Case Presentation: We report a patient with the triad of diabetic ketoacidosis, hypertriglyceridemia, and acute pancreatitis associated with computed tomography hypoperfusion complex and adrenal hyperdensity on abdominal imaging – an association not previously reported in diabetic ketoacidosis.Discussion: Presence of Computed tomography hypoperfusion complex with hyperdense ‘Tubelight adrenals’ in a patient with diabetic ketoacidosis is associated with poor prognosis and thus serves to guide clinicians towards early and aggressive management.

Concentrations of atmospheric trace species in the United States have changed dramatically over the past several decades in response to pollution control strategies, shifts in domestic energy policy and economics, and economic development (and resulting emission changes) elsewhere in the world. Reliable projections of the future atmosphere require models to not only accurately describe current atmospheric concentrations, but to do so by representing chemical, physical and biological processes with conceptual and quantitative fidelity. Only through incorporation of the processes controlling emissions and chemical mechanisms that represent the key transformations among reactive molecules can models reliably project the impacts of future policy, energy and climate scenarios. Efforts to properly identify and implement the fundamental and controlling mechanisms in atmospheric models benefit from intensive observation periods, during which collocated measurements of diverse, speciated chemicals in both the gas and condensed phases are obtained. The Southeast Atmosphere Studies (SAS, including SENEX, SOAS, NOMADSS and SEAC4RS) conducted during the summer of 2013 provided an unprecedented opportunity for the atmospheric modeling community to come together to evaluate, diagnose and improve the representation of fundamental climate and air quality processes in models of varying temporal and spatial scales. This paper is aimed at discussing progress in evaluating, diagnosing and improving air quality and climate modeling using comparisons to SAS observations as a guide to thinking about improvements to mechanisms and parameterizations in models. The effort focused primarily on model representation of fundamental atmospheric processes that are essential to the formation of ozone, secondary organic aerosol (SOA) and other trace species in the troposphere, with the ultimate goal of understanding the radiative impacts of these species in the southeast and elsewhere. Here we address questions surrounding four key themes: gas-phase chemistry, aerosol chemistry, regional climate and chemistry interactions, and natural and anthropogenic emissions. We expect this review to serve as a guidance for future modeling efforts.

Background: Reductions in ambient concentrations of fine particulate matter ([PM.sub.2.5]) have contributed to reductions in cardiovascular (CV) mortality. Objectives: We examined changes in CV mortality attributed to reductions in emissions from mobile, point, areal, and nonroad sources through changes in concentrations of [PM.sub.2.5] and its major components [nitrates, sulfates, elemental carbon (EC), and organic carbon (OC)] in 2,132 U.S. counties between 1990 and 2010. Methods: Using Community Multiscale Air Quality model estimated [PM.sub.2.5] total and component concentrations, we calculated population-weighted annual averages for each county. We estimated [PM.sub.2.5] total- and component-related CV mortality, adjusted for county-level population characteristics and baseline [PM.sub.2.5] concentrations. Using the index of Emission Mitigation Efficiency for primary emission-to-particle pathways, we expressed changes in particle-related mortality in terms of precursor emissions by each sector. Results: [PM.sub.2.5] reductions represented 5.7% of the overall decline in CV mortality. Large point source emissions of sulfur dioxide accounted for 6.685 [95% confidence interval (CI): 5.703, 7.667] fewer sulfate-related CV deaths per 100,000 people. Mobile source emissions of primary EC and nitrous oxides accounted for 3.396 (95% CI: 2.772, 4.020) and 3.984 (95% CI: 2.472, 5.496) fewer CV deaths per 100,000 people respectively. Increased EC and OC emissions from areal sources increased carbon-related CV mortality by 0.788 (95% CI: -0.540, 2.116) and 0.245 (95% CI: -0.697, 1.187) CV deaths per 100,000 people. Discussion: In a nationwide epidemiological study of emission sector contribution to [PM.sub.2.5]-related mortality, we found that reductions in sulfurdioxide emissions from large point sources and nitrates and EC emissions from mobile sources contributed the largest reduction in particle-related mortality rates respectively. https://doi.org/10.1289/EHP5692, Introduction The Clean Air Act Amendments of 1990 led to the establishment of national, regional, and source-specific regulations that significantly decreased ambient concentrations of fine particulate matter ([PM.sub.2.5]) in many [...]

Comparison of lightning flash data from the National Lightning Detection Network (NLDN) and from the World Wide Lightning Location Network (WWLLN) over the contiguous United States (CONUS) for the 2016–2018 period reveals temporally and spatially varying flash rates that would influence lightning NOx (LNOx) production due to known detection efficiency differences especially during summer months over land (versus over ocean). However, the lightning flash density differences between the two networks show persistent seasonal patterns over geographical regions (e.g., land versus ocean). Since the NLDN data are considered to have higher accuracy (lightning detection with >95% efficiency), we developed scaling factors for the WWLLN flash data based on the ratios of WWLLN to NLDN flash data over time (months of year) and space. In this study, sensitivity simulations using the Community Multiscale Air Quality (CMAQ) model are performed utilizing the original data sets (both NLDN and WWLLN) and the scaled WWLLN flash data for LNOx production over the CONUS. The model performance of using the different lightning flash datasets for ambient O3 and NOx mixing ratios that are directly impacted by LNOx emissions and the wet and dry deposition of oxidized nitrogen species that are indirectly impacted by LNOx emissions is assessed based on comparisons with ground-based observations, vertical profile measurements, and satellite products. During summer months, the original WWLLN data produced less LNOx emissions (due to its lower lightning detection efficiency) compared to the NLDN data, which resulted in less improvement in model performance than the simulation using NLDN data as compared to the simulation without any LNOx emissions. However, the scaled WWLLN data produced LNOx estimates and model performance comparable with the NLDN data, suggesting that scaled WWLLN may be used as a substitute for the NLDN data to provide LNOx estimates in air quality models when the NLDN data are not available (e.g., due to prohibitive cost or lack of spatial coverage). [ABSTRACT FROM AUTHOR]

The National Air Quality Forecast Capability (NAQFC) currently provides next-day forecasts of ozone concentrations over the contiguous United States. It was developed collaboratively by NOAA and Environmental Protection Agency (EPA) in order to provide state and local agencies, as well as the general public, air quality forecast guidance. As part of the development process, the NAQFC has been evaluated utilizing strict monitor-to-gridcell matching criteria, and discrete-type statistics of forecast concentrations. While such an evaluation is important to the developers, it is equally, if not more important, to evaluate the performance using the same protocol as the model's intended application. Accordingly, the purpose of this article is to demonstrate the efficacy of the NAQFC from the perspective of a local forecaster, thereby promoting its use. Such an approach has required the development of a new evaluation protocol: one that examines the ability of the NAQFC to forecast values of the EPA's Air Quality Index (AQI) rather than ambient air concentrations; focuses on the use of categorical-type statistics related to exceedances and nonexceedances; and, most challenging, examines performance, not based on matched grid cells and monitors, but rather over a 'local forecast region,' such as an air shed or metropolitan statistical area (MSA). Results from this approach, which is demonstrated for the Charlotte, North Carolina, MSA and subsequently applied to four additional MSAs during the summer of 2007, reveal that the quality of the NAQFC forecasts is generally comparable to forecasts from local agencies. Such findings will hopefully persuade forecasters, whether they are experienced with numerous tools at their disposal or inexperienced with limited resources, to utilize the NAQFC as forecast guidance. DOI: 10.1175/2009BAMS2734.1

BACKGROUND: Air quality across the northern hemisphere over the past two decades has witnessed dramatic changes, with continuous improvement in developed countries in North America and Europe, but a contrasting sharp deterioration in developing regions of Asia. OBJECTIVE: This study investigates the historical trend in the long-term exposure to [PM.sub.2.5] and [PM.sub.2.5]-related premature mortality ([PM.sub.2.5]-mortality) and its response to changes in emission that occurred during 1990-2010 across the northern hemisphere. Implications for future trends in human exposure to air pollution in both developed and developing regions of the world are discussed. METHODS: We employed the integrated exposure-response model developed by Health Effects Institute to estimate the [PM.sub.2.5]-mortality. The 1990-2010 annual average [PM.sub.2.5] concentrations were obtained from the simulations using the WRF-CMAQ model. Emission mitigation efficiencies of sulfur dioxide (S[O.sub.2]), nitrogen oxides (N[O.sub.x]), ammonia (N[H.sub.3]), and primary PM are estimated from the [PM.sub.2.5]-mortality responses to the emission variations. RESULTS: Estimated [PM.sub.2.5]-mortalities in East Asia and South Asia increased by 21% and 85% respectively, from 866,000 and 578,000 in 1990, to 1,048,000 and 1,068,000 in 2010. [PM.sub.2.5]-mortalities in developed regions (i.e., Europe and high-income North America) decreased substantially by 67% and 58% respectively. CONCLUSIONS: Over the past two decades, correlations between population and [PM.sub.2.5] have become weaker in Europe and North America due to air pollution controls but stronger in East Asia due to deteriorating air quality. Mitigation of primary PM appears to be the most efficient way for increasing health benefits (i.e., providing the largest mortality reduction per unit emissions). However, reductions in emissions of N[H.sub.3] are needed to maximize the effectiveness of N[O.sub.x] emission controls. http://dx.doi.org/10.1289/EHP298, Introduction Fine particles--those defined as aerosols with aerodynamic diameter ≤ 2.5 µm ([PM.sub.2.5])--in the atmosphere have been well known for their potential negative impacts on human health that can affect [...]

Condensable particulate matter (CPM) emitted from stationary combustion and mobile sources exhibits high emissions and a large proportion of organic components. However, CPM is not generally measured when conducting emission surveys of PM in most countries, including China. Consequently, previous emission inventories have not included emission rates for CPM. Here we construct an emission inventory of CPM in China with a focus on organic aerosols (OA) based on collected CPM emission information. Results show that OA emissions are enhanced twofold after the inclusion of CPM in a new China inventory for the years 2014 and 2017. Considering organic CPM emissions and model representations of secondary OA (SOA) formation from CPM, here a series of sensitivity cases have been simulated using the three-dimensional Community Multiscale Air Quality (CMAQ) model to estimate the contributions of CPM emissions to atmospheric OA and fine PM (PM2.5) concentrations in China. Compared with observations during a haze episode from October 14 to November 14, 2014, at a Beijing site, estimates of temporal average primary OA (POA) and SOA concentrations are greatly improved after including the CPM effects. These scenarios demonstrated the significant contributions of CPM emissions from stationary combustion and mobile sources to POA (53 ~ 86 %), SOA (48 ~ 67 %), and total OA concentrations (50 ~ 78 %). Furthermore, contributions of CPM emissions to total OA concentrations were demonstrated over the major 2+26 cities of Beijing-Tianjin-Hebei region (BTH2+26 cities) in December 2018, with average contributions up to 55 %, 58 %, 60 %, and 57 % for Handan, Shijiazhuang, Xingtai, and Dezhou, respectively. Correspondingly, the inclusion of CPM emissions also narrowed the gap between simulated and observed PM2.5 concentrations over the BTH2+26 cities. These results improve the simulation performance of atmospheric OA and PM2.5, and may provide important implications for the sources of OA. [ABSTRACT FROM AUTHOR]

Airborne aerosols reduce surface solar radiation through light scattering and absorption (aerosol direct effects, ADE), influence regional meteorology, and further affect atmospheric chemical reactions and aerosol concentrations. Several studies have revealed that the inhibition of turbulence and the increase in atmospheric stability induced by ADE increases surface primary aerosol concentration, but the pathway of ADE impacts on secondary aerosol is still unclear. In this study, the two-way coupled WRF-CMAQ with integrated process analysis was applied to explore how ADE impacts secondary aerosol formation through changes in atmospheric dynamics and photolysis processes. Meteorological and air quality fields in Jing-Jin-Ji area (denoted JJJ, including Beijing, Tianjin and Hebei Province in China) in January and July 2013 were simulated to represent winter and summer conditions, respectively. Two pathways of ADE impacts on aerosol concentration, i.e., photolysis modification and atmospheric dynamics modification were estimated separately through scenario analysis. The results show that solar radiation is the restricting factor in winter, and the formation of sulfate is sensitive to the perturbation of solar radiation. While in summer, availability of gaseous precursors primarily dictates the levels of secondary aerosol concentrations. ADE through the attenuation of photolysis inhibits secondary aerosol formation during winter and promotes secondary aerosol formation during summer. The seasonal differences are attributed to change of effective actinic flux in winter and summer determined by aerosol optical depth, solar zenith angles, and single scattering albedo. ADE through dynamic processes is the dominant process influencing surface secondary aerosol formation due to the accumulation of gaseous precursors. Different from sulfate, the surface layer is a net-source of nitrate during winter but a sink during summer. Therefore, ADE promotes nitrate accumulation in winter and reduces nitrate accumulation in summer. [ABSTRACT FROM AUTHOR]