Top-Down NOx Emissions of European Cities Based on the Downwind Plume of Modelled and Space-Borne Tropospheric NO2 Columns

Top-down estimates of surface NOX emissions were derived for 23 European cities based on the downwind plume decay of tropospheric nitrogen dioxide (NO2) columns from the LOTOS-EUROS (Long Term Ozone Simulation-European Ozone Simulation) chemistry transport model (CTM) and from Ozone Monitoring Instrument (OMI) satellite retrievals, averaged for the summertime period (April-September) during 2013. Here we show that the top-down NOX emissions derived from LOTOS-EUROS for European urban areas agree well with the bottom-up NOX emissions from the MACC-III inventory data (R(exp 2) = 0.88) driving the CTM demonstrating the potential of this method. OMI top-down NOX emissions over the 23 European cities are generally lower compared with the MACC-III emissions and their correlation is slightly lower (R(exp 2) = 0.79). The uncertainty on the derived NO2 lifetimes and NOX emissions are on average ~55% for OMI and ~63% for LOTOS-EUROS data. The downwind NO2 plume method applied on both LOTOS-EUROS and OMI tropospheric NO2 columns allows to estimate NOX emissions from urban areas, demonstrating that this is a useful method for real-time updates of urban NOX emissions with reasonable accuracy

Detection and attribution of an anomaly in terrestrial photosynthesis in Europe during the COVID-19 lockdown

Carbon dioxide (CO2) uptake by plant photosynthesis, referred to as gross primary production (GPP) at the ecosystem level, is sensitive to environmental factors, including pollutant exposure, pollutant uptake, and changes in the scattering of solar shortwave irradiance (SWin) - the energy source for photosynthesis. The 2020 spring lockdown due to COVID-19 resulted in improved air quality and atmospheric transparency, providing a unique opportunity to assess the impact of air pollutants on terrestrial ecosystem functioning. However, detecting these effects can be challenging as GPP is influenced by other meteorological drivers and management practices. Based on data collected from 44 European ecosystem-scale CO2 flux monitoring stations, we observed significant changes in spring GPP at 34 sites during 2020 compared to 2015-2019. Among these, 14 sites showed an increase in GPP associated with higher SWin, 10 sites had lower GPP linked to atmospheric and soil dryness, and seven sites were subjected to management practices. The remaining three sites exhibited varying dynamics, with one experiencing colder and rainier weather resulting in lower GPP, and two showing higher GPP associated with earlier spring melts. Analysis using the regional atmospheric chemical transport model (LOTOS-EUROS) indicated that the ozone (O-3) concentration remained relatively unchanged at the research sites, making it unlikely that O-3 exposure was the dominant factor driving the primary production anomaly. In contrast, SWin increased by 9.4 % at 36 sites, suggesting enhanced GPP possibly due to reduced aerosol optical depth and cloudiness. Our findings indicate that air pollution and cloudiness may weaken the terrestrial carbon sink by up to 16 %. Accurate and continuous ground-based observations are crucial for detecting and attributing subtle changes in terrestrial ecosystem functioning in response to environmental and anthropogenic drivers

Predictors of NOAC versus VKA use for stroke prevention in patients with newly diagnosed atrial fibrillation: Results from GARFIELD-AF.

INTRODUCTION: A principal aim of the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) was to document changes in treatment practice for patients with newly diagnosed atrial fibrillation during an era when non-vitamin K antagonist oral anticoagulants (NOACs) were becoming more widely adopted. In these analyses, the key factors which determined the choice between NOACs and vitamin K antagonists (VKAs) are explored. METHODS: Logistic least absolute shrinkage and selection operator regression determined predictors of NOAC and VKA use. Data were collected from 24,137 patients who were initiated on AC ± antiplatelet (AP) therapy (NOAC [51.4%] or VKA [48.6%]) between April 2013 and August 2016. RESULTS: The most significant predictors of AC therapy were country, enrolment year, care setting at diagnosis, AF type, concomitant AP, and kidney disease. Patients enrolled in emergency care or in the outpatient setting were more likely to receive a NOAC than those enrolled in hospital (OR 1.16 [95% CI: 1.04-1.30], OR: 1.15 [95% CI: 1.05-1.25], respectively). NOAC prescribing seemed to be favored in lower-risk groups, namely, patients with paroxysmal AF, normotensive patients, and those with moderate alcohol consumption, but also the elderly and patients with acute coronary syndrome. By contrast, VKAs were preferentially used in patients with permanent AF, moderate to severe kidney disease, heart failure, vascular disease, and diabetes and with concomitant AP. CONCLUSION: GARFIELD-AF data highlight marked heterogeneity in stroke prevention strategies globally. Physicians are adopting an individualized approach to stroke prevention where NOACs are favored in patients with a lower stroke risk but also in the elderly and patients with acute coronary syndrome

CAMSvsTROPOMI: Comparison of CAMS regional models with TROPOMI NO2

This is a software to read and compare tropospheric NO2 columns derived from the Copernicus Atmospheric Monitoring Service's (CAMS) regional air quality model output with TROPOMI tropospheric columns. Data are read in the format they are supplied but the respective outlets, namely the CAMS Atmosphere Data Store and the Copernicus Open Access Hub. Output is provided either at the model grid or as enhanced TROPOMI level-2 product files with additional fields.v0.21 now includes a sourcefile which was missing in v0.

Top-down NO_x emissions of european cities based on the downwind plume of modelled and space-borne tropospheric NO₂ columns

Top-down estimates of surface NOX emissions were derived for 23 European cities based on the downwind plume decay of tropospheric nitrogen dioxide (NO2) columns from the LOTOS-EUROS (Long Term Ozone Simulation-European Ozone Simulation) chemistry transport model (CTM) and from Ozone Monitoring Instrument (OMI) satellite retrievals, averaged for the summertime period (April–September) during 2013. Here we show that the top-down NOX emissions derived from LOTOS-EUROS for European urban areas agree well with the bottom-up NOX emissions from the MACC-III inventory data (R2 = 0.88) driving the CTM demonstrating the potential of this method. OMI top-down NOX emissions over the 23 European cities are generally lower compared with the MACC-III emissions and their correlation is slightly lower (R2 = 0.79). The uncertainty on the derived NO2 lifetimes and NOX emissions are on average ~55% for OMI and ~63% for LOTOS-EUROS data. The downwind NO2 plume method applied on both LOTOS-EUROS and OMI tropospheric NO2 columns allows to estimate NOX emissions from urban areas, demonstrating that this is a useful method for real-time updates of urban NOX emissions with reasonable accuracy.</p

Recommendations for the spatial assessment of air quality resulting from the FP6 EU project Air4EU

Original article can be found at : http://www.inderscience.com/ Copyright Inderscience [Full text of this article is not available in the UHRA]Air4EU is an FP6 European project with the major aim of providing recommendations on methodologies for the spatial assessment of air quality on local, urban and regional scales. The emphasis is on methodologies that combine monitoring and modelling and on spatial assessment for regulatory purposes, i.e., the EU daughter directives. The recommendations coming from Air4EU are intended as guidance for authorities involved in air quality assessment at the city, national and European levels as well as institutes involved in air quality research and application. This paper provides some highlights from the recommendations and case studies that emerged from the project.Peer reviewe

Comparing Sentinel-5P TROPOMI NO2 column observations with the CAMS regional air quality ensemble

The Sentinel-5P TROPOspheric Monitoring Instrument (TROPOMI) instrument, launched in October 2017, provides unique observations of atmospheric trace gases at a high resolution of about 5gkm, with near-daily global coverage, resolving individual sources like thermal powerplants, industrial complexes, fires, medium-scale towns, roads, and shipping routes. Even though Sentinel-5P (S5P) is a global mission, these datasets are especially well suited to test high-resolution regional-scale air quality (AQ) models and provide valuable input for emission inversion systems. In Europe, the Copernicus Atmosphere Monitoring Service (CAMS) has implemented an operational regional AQ forecasting capability based on an ensemble of several European models, available at a resolution of 0.1g. In this paper, we present comparisons between TROPOMI observations of nitrogen dioxide (NO2) and the CAMS AQ forecasts and analyses of NO2. We discuss the different ways of making these comparisons and present quantitative results in the form of maps for individual days, summer and winter months, and a time series for European subregions and cities between May 2018 and March 2021. The CAMS regional products generally capture the fine-scale daily and averaged features observed by TROPOMI in much detail. In summer, the comparison shows a close agreement between TROPOMI and the CAMS ensemble NO2 tropospheric columns with a relative difference of up to 15g% for most European cities. In winter, however, we find a significant discrepancy in the column amounts over much of Europe, with relative differences up to 50g%. The possible causes for these differences are discussed, focusing on the possible impact of retrieval and modeling errors. Apart from comparisons with the CAMS ensemble, we also present results for comparisons with the individual CAMS models for selected months. Furthermore, we demonstrate the importance of the free tropospheric contribution to the estimation of the tropospheric column and thus include profile information from the CAMS configuration of the ECMWF's (European Centre for Medium-Range Weather Forecasts) global integrated model above 3gkm altitude in the comparisons. We also show that replacing the global 1g a priori information in the retrieval by the regional 0.1g resolution profiles of CAMS leads to significant changes in the TROPOMI-retrieved tropospheric column, with typical increases at the emission hotspots up to 30g% and smaller increases or decreases elsewhere. As a spinoff, we present a new TROPOMI NO2 level 2 (L2) data product for Europe, based on the replacement of the original TM5-MP generated global a priori profile by the regional CAMS ensemble profile. This European NO2 product is compared with ground-based remote sensing measurements of six Pandora instruments of the Pandonia Global Network and nine Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) instruments. As compared to the standard S5P tropospheric NO2 column data, the overall bias of the new product for all except two stations is 5g% to 12g% smaller, owing to a reduction in the multiplicative bias. Compared to the CAMS tropospheric NO2 columns, dispersion and correlation parameters with respect to the standard data are, however, superior

Comparing Sentinel-5P TROPOMI NO2 column observations with the CAMS-regional air quality ensemble

International audienceThe Sentinel-5P TROPOMI instrument provides unique observations of atmospheric trace gases at a high resolution of about 5 km with near-daily global coverage, resolving individual sources like thermal power plants, industrial complexes, fires, medium-scale towns, roads and shipping routes. These datasets are especially well suited to test high-resolution regional-scale air quality (AQ) models and provide valuable input for regional emission inversion systems. In Europe, the Copernicus Atmosphere Monitoring Service (CAMS) has implemented an operational regional AQ forecasting capability for Europe based on an ensemble of 7 up to 11 European models. In the presentation we show comparisons between TROPOMI observations of nitrogen dioxide (NO2) and the CAMS AQ forecasts and analyses of NO2. We discuss the different ways of making these comparisons, and present the quantitative results for time series for regions and cities between May 2018 to March 2021, for summer and winter months and individual days. We demonstrate the importance of the free tropospheric contribution to the tropospheric column, and include profiles from the CAMS configuration of the ECMWF’s global integrated model above 3 km altitude in the comparison. The models generally capture the fine-scale daily and averaged features observed by TROPOMI in much detail. In summer, the quantitative comparison of the NO2 tropospheric column shows a close agreement, but in winter we find a significant discrepancy in the average column amount over Europe. Recently a new TROPOMI NO2 reprocessing with processor version 2.3.1 has become available, and impact of this new version on the comparisons is discussed. As spin-off, we present a new TROPOMI NO2 level-2 data product for Europe, based on the replacement of the original TM5-MP generated global a priori profile (1x1 degree resolution) by the regional CAMS ensemble profile at 0.1x0.1 degree resolution. This a-priori replacement leads to significant changes in the TROPOMI retrieved tropospheric column, with typical increases at the emission hotspots in the order of 20%. The European NO2 product is compared with ground-based remote sensing measurements of 6 PANDORA instruments of the Pandonia global network and 8 MAX-DOAS instruments. As compared to the standard S5P tropospheric NO2 column data, the overall bias of the new product is smaller owing to a reduction of the multiplicative bias linked to the profile shape