In 2014, the International Endohernia Society (IEHS) published the first international "Guidelines for laparoscopic treatment of ventral and incisional abdominal wall hernias." Guidelines reflect the currently best available evidence in diagnostics and therapy and give recommendations to help surgeons to standardize their techniques and to improve their results. However, science is a dynamic field which is continuously developing. Therefore, guidelines require regular updates to keep pace with the evolving literature. Methods For the development of the original guidelines, all relevant literature published up to year 2012 was analyzed using the ranking of the Oxford Centre for Evidence-Based Medicine. For the present update, all of the previous authors were asked to evaluate the literature published during the recent years from 2012 to 2017 and revise their statements and recommendations given in the initial guidelines accordingly. In two Consensus Conferences (October 2017 Beijing, March 2018 Cologne), the updates were presented, discussed, and confirmed. To avoid redundancy, only new statements or recommendations are included in this paper. Therefore, for full understanding both of the guidelines, the original and the current, must be read. In addition, the new developments in repair of abdominal wall hernias like surgical techniques within the abdominal wall, release operations (transversus muscle release, component separation), Botox application, and robot-assisted repair methods were included. Results Due to an increase of the number of patients and further development of surgical techniques, repair of primary and secondary abdominal wall hernias attracts increasing interests of many surgeons. Whereas up to three decades ago hernia-related publications did not exceed 20 per year, currently this number is about 10-fold higher. Recent years are characterized by the advent of new techniques-minimal invasive techniques using robotics and laparoscopy, totally extraperitoneal repairs, novel myofascial release techniques for optimal closure of large defects, and Botox for relaxing the abdominal wall. Furthermore, a concomitant rectus diastasis was recognized as a significant risk factor for recurrence. Despite insufficient evidence with respect to these new techniques, it seemed to us necessary to include them in the update to stimulate surgeons to do research in these fields. Conclusion Guidelines are recommendations based on best available evidence intended to help the surgeon to improve the quality of his daily work. However, science is a continuously evolving process, and as such guidelines should be updated about every 3 years. For a comprehensive reference, however, it is suggested to read both the initial guidelines published in 2014 together with the update. Moreover, the presented update includes also techniques which were not known 3 years before.

Abstract. An updated version of the nested-grid GEOSChem model is developed allowing for higher horizontal (0.5 • ×0.667 • ) resolution as compared to global models. CO transport over a heavily polluted region, the Beijing-TianjinHebei (BTH) city cluster in China, and the pattern of outflow from East China in summertime are investigated. Comparison of the nested-grid with global models indicates that the fine-resolution nested-grid model is capable of resolving individual cities with high associated emission intensities. The nested-grid model indicates the presence of a high CO column density over the Sichuan Basin in summer, attributable to the low-level stationary vortex associated with the Basin's topographical features. The nested-grid model provides good agreement also with measurements from a suburban monitoring site in Beijing during summer 2005. Tagged CO simulation results suggest that regional emissions make significant contributions to elevated CO levels over Beijing on polluted days and that the southeastward moving cyclones bringing northwest winds to Beijing are the key meteorological mechanisms responsible for dispersion of pollution over Beijing in summer. Overall CO fluxes to the NW Pacific from Asia are found to decrease by a factor of 3-4 from spring to summer. Much of the seasonal change is driven by decreasing fluxes from India and Southeast Asia in summer, while fluxes from East China are only 30% lower in summer than in spring. Compared to spring, summertime outflow from Chinese source regions is strongest at higher latitudes (north of 35 • N). The deeper convection in summer transporting CO to higher altitudes where export is more efficient is largely responsible for enhanced export in summer.

Abstract. In an attempt to improve the forecasting of atmospheric aerosols, the ensemble square root filter algorithm was extended to simultaneously optimize the chemical initial conditions (ICs) and emission input. The forecast model, which was expanded by combining the Weather Research and Forecasting with Chemistry (WRF-Chem) model and a forecast model of emission scaling factors, generated both chemical concentration fields and emission scaling factors. The forecast model of emission scaling factors was developed by using the ensemble concentration ratios of the WRF-Chem forecast chemical concentrations and also the time smoothing operator. Hourly surface fine particulate matter (PM 2.5 ) observations were assimilated in this system over China from 5 to 16 October 2014. A series of 48 h forecasts was then carried out with the optimized initial conditions and emissions on each day at 00:00 UTC and a control experiment was performed without data assimilation. In addition, we also performed an experiment of pure assimilation chemical ICs and the corresponding 48 h forecasts experiment for comparison. The results showed that the forecasts with the optimized initial conditions and emissions typically outperformed those from the control experiment. In the Yangtze River delta (YRD) and the Pearl River delta (PRD) regions, large reduction of the root-mean-square errors (RMSEs) was obtained for almost the entire 48 h forecast range attributed to assimilation. In particular, the relative reduction in RMSE due to assimilation was about 37.5 % at nighttime when WRF-Chem performed comparatively worse. In the BeijingTianjin-Hebei (JJJ) region, relatively smaller improvements were achieved in the first 24 h forecast but then no improvements were achieved afterwards. Comparing to the forecasts with only the optimized ICs, the forecasts with the joint adjustment were always much better during the night in the PRD and YRD regions. However, they were very similar during daytime in both regions. Also, they performed similarly for almost the entire 48 h forecast range in the JJJ region.

Abstract. Extreme haze events have occurred frequently over China in recent years. Although many studies have investigated the formation mechanisms associated with PM2.5 for heavily polluted regions in China based on observational data, adequately predicting peak PM2.5 concentrations is still challenging for regional air quality models. In this study, we evaluate the performance of one configuration of the Weather Research and Forecasting model coupled with chemistry (WRF-Chem) and use the model to investigate the sensitivity of heterogeneous reactions on simulated peak sulfate, nitrate, and ammonium concentrations in the vicinity of Beijing during four extreme haze episodes in October 2014 over the North China Plain. The highest observed PM2.5 concentration of 469 µg m−3 occurred in Beijing. Comparisons with observations show that the model reproduced the temporal variability in PM2.5 with the highest PM2.5 values on polluted days (defined as days in which observed PM2.5 is greater than 75 µg m−3), but predictions of sulfate, nitrate, and ammonium were too low on days with the highest observed concentrations. Observational data indicate that the sulfur/nitric oxidation rates are strongly correlated with relative humidity during periods of peak PM2.5; however, the model failed to reproduce the highest PM2.5 concentrations due to missing heterogeneous/aqueous reactions. As the parameterizations of those heterogeneous reactions are not well established yet, estimates of SO2-to-H2SO4 and NO2/NO3-to-HNO3 reaction rates that depend on relative humidity were applied, which improved the simulation of sulfate, nitrate, and ammonium enhancement on polluted days in terms of both concentrations and partitioning among those species. Sensitivity simulations showed that the extremely high heterogeneous reaction rates and also higher emission rates than those reported in the emission inventory were likely important factors contributing to those peak PM2.5 concentrations.

Abstract. Using OMI (Ozone Monitoring Instrument) tropospheric NO 2 columns and a nested-grid 3-D global chemical transport model (GEOS-Chem), we investigated the growth in NO x emissions from coal-fired power plants and their contributions to the growth in NO 2 columns in 2005-2007 in China. We first developed a unit-based power plant NO x emission inventory for [2005][2006][2007] to support this investigation. The total capacities of coal-fired power generation have increased by 48.8 % in 2005-2007, with 92.2 % of the total capacity additions coming from generator units with size ≥300 MW. The annual NO x emissions from coal-fired power plants were estimated to be 8.11 Tg NO 2 for 2005 and 9.58 Tg NO 2 for 2007, respectively. The modeled summer average tropospheric NO 2 columns were highly correlated (R 2 = 0.79-0.82) with OMI measurements over grids dominated by power plant emissions, with only 7-14 % low bias, lending support to the high accuracy of the unitbased power plant NO x emission inventory. The ratios of OMI-derived annual and summer average tropospheric NO 2 columns between 2007 and 2005 indicated that most of the grids with significant NO 2 increases were related to power plant construction activities. OMI had the capability to trace the changes of NO x emissions from individual large power plants in cases where there is less interference from other NO x sources. Scenario runs from GEOS-Chem model suggested that the new power plants contributed 18.5 % and 10 % to the annual average NO 2 columns in 2007 in Inner Mongolia and North China, respectively. The massive new power plant NO x emissions significantly changed the local NO 2 profiles, especially in less polluted areas. A sensitivity study found that changes of NO 2 shape factors due to including new power plant emissions increased the summer average OMI tropospheric NO 2 columns by 3.8-17.2 % for six selected locations, indicating that the updated emission information could help to improve the satellite retrievals.

Abstract. An ensemble Kalman filter data assimilation (DA) system has been developed to improve air quality forecasts using surface measurements of PM10, PM2.5, SO2, NO2, O3, and CO together with an online regional chemical transport model, WRF-Chem (Weather Research and Forecasting with Chemistry). This DA system was applied to simultaneously adjust the chemical initial conditions (ICs) and emission inputs of the species affecting PM10, PM2.5, SO2, NO2, O3, and CO concentrations during an extreme haze episode that occurred in early October 2014 over East Asia. Numerical experimental results indicate that ICs played key roles in PM2.5, PM10 and CO forecasts during the severe haze episode over the North China Plain. The 72 h verification forecasts with the optimized ICs and emissions performed very similarly to the verification forecasts with only optimized ICs and the prescribed emissions. For the first-day forecast, near-perfect verification forecasts results were achieved. However, with longer-range forecasts, the DA impacts decayed quickly. For the SO2 verification forecasts, it was efficient to improve the SO2 forecast via the joint adjustment of SO2 ICs and emissions. Large improvements were achieved for SO2 forecasts with both the optimized ICs and emissions for the whole 72 h forecast range. Similar improvements were achieved for SO2 forecasts with optimized ICs only for the first 3 h, and then the impact of the ICs decayed quickly. For the NO2 verification forecasts, both forecasts performed much worse than the control run without DA. Plus, the 72 h O3 verification forecasts performed worse than the control run during the daytime, due to the worse performance of the NO2 forecasts, even though they performed better at night. However, relatively favorable NO2 and O3 forecast results were achieved for the Yangtze River delta and Pearl River delta regions.

<p><strong>Abstract.</strong> Extreme haze events have occurred frequently over China in recent years. Although many studies have investigated the formation mechanisms associated with PM<sub>2.5</sub> for heavily polluted regions in China based on observational data, adequately predicting peak PM<sub>2.5</sub> concentrations is still challenging for regional air quality models. In this study, we evaluate the performance of one configuration of the Weather Research and Forecasting model coupled with chemistry (WRF-Chem) and use the model to investigate the sensitivity of heterogeneous reactions on simulated peak sulfate, nitrate, and ammonium concentrations in the vicinity of Beijing during four extreme haze episodes in October 2014 over the North China Plain. The highest observed PM<sub>2.5</sub> concentration of 469 μg m<sup>-3</sup> occurred in Beijing. Comparisons with observations show that the model reproduced the temporal variability in PM<sub>2.5</sub> with the highest PM<sub>2.5</sub> values on polluted days (defined as days in which observed PM<sub>2.5</sub> is greater than 75 μg m<sup>-3</sup>), but predictions of sulfate, nitrate, and ammonium were too low on days with the highest observed concentrations. Observational data indicate that the sulfur/nitric oxidation rates are strongly correlated with relative humidity during periods of peak PM<sub>2.5</sub>; however, the model failed to reproduce the highest PM<sub>2.5</sub> concentrations due to missing heterogeneous reactions. As the parameterizations of those reactions is not well established yet, estimates of SO<sub>2</sub>-to-H<sub>2</sub>SO<sub>4</sub> and NO<sub>2</sub>/NO<sub>3</sub>-to-HNO<sub>3</sub> reaction rates that depend on relative humidity were applied which improved the simulation of sulfate, nitrate, and ammonium enhancement on polluted days in terms of both concentrations and partitioning among those species. Sensitivity simulations showed that the extremely high heterogeneous reaction rates and also higher emission rates than those reported in the emission inventory were likely important factors contributing to those peak PM<sub>2.5</sub> simulations.</p>

Abstract. We estimate biomass burning and anthropogenic emissions of black carbon (BC) in the western US for MayOctober 2006 by inverting surface BC concentrations from the Interagency Monitoring of PROtected Visual Environment (IMPROVE) network using a global chemical transport model. We first use active fire counts from the Moderate Resolution Imaging Spectroradiometer (MODIS) to improve the spatiotemporal distributions of the biomass burning BC emissions from the Global Fire Emissions Database (GFEDv2). The adjustment primarily shifts emissions from late to middle and early summer (a 33 % decrease in September-October and a 56 % increase in June-August) and leads to appreciable increases in modeled surface BC concentrations in early and middle summer, especially at the 1-2 and 2-3 km altitude ranges. We then conduct analytical inversions at both 2