The Effect of Harmonized Emissions on Aerosol Properties in Global Models an AeroCom Experiment

Abstract. The effects of unified aerosol sources on global aerosol fields simulated by different models are examined in this paper. We compare results from two AeroCom experiments, one with different (ExpA) and one with unified emissions, injection heights, and particle sizes at the source (ExpB). Surprisingly, harmonization of aerosol sources has only a small impact on the simulated inter-model diversity of the global aerosol burden, and consequently global optical properties, as the results are largely controlled by modelspecific transport, removal, chemistry (leading to the formation of secondary aerosols) and parameterizations of aerosol microphysics (e.g., the split between deposition pathways) and to a lesser extent by the spatial and temporal distributions of the (precursor) emissions. The burdens of black carbon and especially sea salt become more coherent in ExpB only, because the large ExpA diversities for these two species were caused by a few outliers. The experiment also showed that despite prescribing emission fluxes and size distributions, ambiguities in the implementation in individual models can lead to substantial differences. These results indicate the need for a better understanding of aerosol life cycles at process level (including spatial dispersal and interaction with meteorological parameters) in order to obtain more reliable results from global aerosol simulations. This is particularly important as such model results are used to assess the consequences of specific air pollution abatement strategies.JRC.H.2-Climate chang

Quantifying the contribution of the Land Use sector to the Paris Climate Agreement

This analysis highlights that the full implementation of all INDCs would significantly decrease LULUCF net GHG emissions in 2030 compared to historical levels. In order to reduce the current high level of uncertainty, additional efforts to improve monitoring and reporting are needed.JRC.H.3-Forest Resources and Climat

North Atlantic Oscillation and tropospheric ozone variability in Europe: model analysis and measurements intercomparison

Ozone pollution represents a serious health and environmental problem. While ozone pollution is mostly produced by photochemistry in summer, elevated ozone concentrations can also be influenced by long range transport driven by the atmospheric circulation and stratospheric ozone intrusions. We analyze the role of large scale atmospheric circulation variability in the North Atlantic basin in determining surface ozone concentrations. Here, we show, using ground station measurements and a coupled atmosphere-chemistry model simulation for the period 1980–2005, that the North Atlantic Oscillation (NAO) does affect surface ozone concentrations – on average, over 10 ppbv on the monthly mean in southwest central and northern Europe – during all seasons except fall. The commonly used NAO index is able to capture the link existing between atmospheric dynamics and surface ozone concentrations in winter and spring but it fails in summer. We find that the first Principal Component, computed from the time variation of the sea level pressure (SLP) field, detects the atmosphere circulation/ozone relationship not only in winter and spring but also during summer, when the atmospheric circulation weakens and regional photochemical processes peak. The first Principal Component of the SLP field could be used as a tool to identify areas more exposed to forthcoming ozone pollution events. Finally, our results suggest that the increasing baseline ozone in western and northern Europe during the 1990s could be related to the prevailing phase of the NAO in that period.JRC.H.7-Climate Risk Managemen

Formation of Secondary Organic Aerosol from Isoprene Oxidation over Europe

The role of isoprene as a precursor to secondary organic aerosol (SOA) over Europe is studied with the two-way nested global chemistry transport model TM5. The inclusion of the formation of SOA from isoprene oxidation in our model almost doubles the atmospheric burden of SOA over Europe compared to SOA formation from terpenes and aromatics. The reference simulation, which considers SOA formation from isoprene, terpenes and aromatics, predicts a yearly European production rate of 1.0 Tg SOA yr-1 and an annual averaged atmospheric burden of about 50 Gg SOA over Europe. A fraction of 35% of the SOA produced in the boundary layer over Europe is transported to higher altitudes or to other world regions. Summertime measurements of particulate organic matter (POM) during the extensive EMEP OC/EC campaign 2002/2003 are better reproduced when SOA formation from isoprene is taken into account, reflecting also the strong seasonality of isoprene and other biogenic volatile organic compounds (BVOC) emissions from vegetation. However, during winter, our model strongly underestimates POM, likely caused by missing wood burning in the emission inventories. Uncertainties in the parameterisation of isoprene SOA formation have been investigated. Maximum SOA production is found for irreversible sticking (non-equilibrium partitioning) of condensable vapours on particles, with tropospheric SOA production over Europe increased by a factor of 4 in summer compared to the reference case. Completely neglecting SOA formation from isoprene results in the lowest estimate (0.51 Tg SOA yr-1). The amount and the nature of the absorbing matter are shown to be another key uncertainty when predicting SOA levels. Tropospheric isoprene SOA production over Europe in summer more than doubles when, in addition to preexisting carbonaceous aerosols, condensation of semi volatile vapours on ammonium and sulphate aerosols is considered. Consequently, smog chamber experiments on SOA formation should be performed with different types of seed aerosols and without seed aerosols in order to derive an improved treatment of the absorption of SOA in the models. Consideration of a number of recent insights in isoprene SOA formation mechanisms reduces the tropospheric production of isoprene derived SOA over Europe from 0.4 Tg yr-1 in our reference simulation to 0.1 Tg yr-1JRC.DDG.H.2-Climate chang

The Applicability of Remote Sensing in the Field of Air Pollution

This report prepared by KNMI and JRC is the final result of a study on the applicability of remote sensing in the field of air pollution requested by the DG Environment. The objectives of this study were to: Have an assessment of presently available scientific information on the feasibility of utilising remote sensing techniques in the implementation of existing legislation, and describe opportunities for realistic streamlining of monitoring in air quality and emissions, based on greater use of remote sensing. Have recommendations for the next policy cycle on the use of remote sensing through development of appropriate provisions and new concepts, including, if appropriate, new environmental objectives, more suited to the use of remote sensing. Have guidance on how to effectively engage with GMES and other initiatives in the air policy field projects Satellite remote sensing of the troposphere is a rapidly developing field. Today several satellite sensors are in orbit that measure trace gases and aerosol properties relevant to air quality. Satellite remote sensing data have the following unique properties: Near-simultaneous view over a large area; Global coverage; Good spatial resolution. The properties of satellite data are highly complementary to ground-based in-situ networks, which provide detailed measurements at specific locations with a high temporal resolution. Although satellite data have distinct benefits, the interpretation is often less straightforward as compared to traditional in-situ measurements. Maps of air pollution measured from space are widespread in the scientific community as well as in the media, and have had a strong impact on the general public and the policy makers. The next step is to make use of satellite data in a quantitative way. Applications based solely on satellite data are foreseen, however an integrated approach using satellite data, ground-based data and models combined with data assimilation, will make the best use of the satellite remote-sensing potential, as well as of the synergy with ground-based observations.JRC.H.4-Transport and air qualit

Effects of business-as-usual anthropogenic emissions on air quality.

The atmospheric chemistry general circulation model EMAC has been used to estimate the impact of anthropogenic emission changes on global and regional air quality in recent and future years (2005, 2010, 2025 and 2050). The emission scenario assumes that population and economic growth largely determine energy and food consumption and consequent pollution sources with the current technologies ("business as usual"). This scenario is chosen to show the effects of not implementing legislation to prevent additional climate change and growing air pollution, other than what is in place for the base year 2005, representing a pessimistic (but feasible) future. By comparing with recent observations, it is shown that the model reproduces the main features of regional air pollution distributions though with some imprecisions inherent to the coarse horizontal resolution (~100 km) and simplified bottom-up emission input. To identify possible future hot spots of poor air quality, a multi pollutant index (MPI), suited for global model output, has been applied. It appears that East and South Asia and the Middle East represent such hotspots due to very high pollutant concentrations, although a general increase of MPIs is observed in all populated regions in the Northern Hemisphere. In East Asia a range of pollutant gases and fine particulate matter (PM2.5) is projected to reach very high levels from 2005 onward, while in South Asia air pollution, including ozone, will grow rapidly towards the middle of the century. Around the Arabian Gulf, where natural PM2.5 concentrations are already high (desert dust), ozone levels are expected to increase strongly. The per capita MPI (PCMPI), which combines demographic and pollutants concentrations projections, shows that a rapidly increasing number of people worldwide will experience reduced air quality during the first half of the 21st century. Following the business as usual scenario, it is projected that air quality for the global average citizen in 2050 would be almost comparable to that for the average citizen in the East Asia in the year 2005, which underscores the need to pursue emission reductions.JRC.H.2-Air and Climat

Support to the review of the Thematic Strategy on Air Pollution: JRC’s contribution to the 2nd Stakeholder meeting January 2012

Although efforts of the EU to reduce air pollution have led to important reductions of emissions within the Member States, millions of people are still exposed to air pollutants at concentration levels that may endanger their health and air pollution is still causing relevant damage to crops and ecosystems. On this background, the European Commission has decided to review its Thematic Strategy for Air Pollution (TSAP) by 2013 at latest, and do this through a consultation process, led by DG ENV, with a broad group of stakeholders. The present report contains the presentations made by JRC staff at the second Stakeholder Meeting, held in January 2012JRC.H.2-Air and Climat

Household Cooking with Solid Fuels Contributes to Ambient PM2.5 Air Pollution and the Burden of Disease

Approximately 2.8 billion people cook with solid fuels, and research has focused on the health impacts of household exposures to fine particulate (PM2.5). Here, as part of the 2010 Global Burden of Disease project, we evaluate the impact of household cooking with solid fuels on regional ambient PM2.5 pollution. We estimated the proportion of ambient PM2.5 (APM2.5) from PM2.5-cooking for the years 1990, 2005, and 2010 in 176 countries, and use these to estimate ambient concentrations of PM2.5 attributable to household cooking with solid fuels (PM2.5-cooking). We used an energy supply-driven emissions model (GAINS) to calculate the fraction of total household PM2.5 emissions produced by cooking with solid fuels, by country. These findings were multiplied by the proportion of total APM2.5 attributable to household emissions, as calculated with the source-receptor model TM5-FASST, to obtain the proportion of total APM2.5 from PM2.5-cooking. In 2010, the proportion of APM2.5 from PM2.5-cooking ranged from 0% of total APM2.5 in six higher-income regions, to 44% (8 µg/m3 of 18 µg/m3 16 total) in Southern sub-Saharan Africa. PM2.5-cooking constituted >10% of APM2.5 in eight regions with 4 billion people, with a global mean of 14%. Globally, the mean population-weighted outdoor air pollution contribution of household cooking was 4 µg/m3 , with the highest contribution of 10 µg/m3 in South Asia. We conclude that PM2.5 emissions from household cooking constitute an important portion of APM2.5 concentrations in many regions, including India and China. Efforts to improve ambient air quality will be hindered if household cooking conditions are not addressed.JRC.H.2-Air and Climat

Global trends of methane emissions and their impacts on ozone concentrations

CH4 is an important greenhouse gas and also a precursor of the air pollutant O3. About 60% of the current global methane is emitted by sources like agriculture, landfills and wastewater, and the production and pipeline transport of fossil fuels, while ca. 40 % is from natural sources. At world level, CH4 emissions and concentrations are still increasing, raising concerns for air quality and climate change. This study, building on evidence from observations and modelling, suggests that CH4 emission reductions can play a key-role in further reducing O3 in Europe and in the world. Since Europe’s contribution to global CH4 emissions is currently only about 6 %, global cooperation to reduce CH4 in countries and regions in- and outside of the EU, will also be essential to reduce related O3 effects in Europe and the world.JRC.C.5-Air and Climat

Better constraints on sources of carbonaceous aerosols using a combined 14C – macro tracer analysis in a European rural background site

The source contributions to carbonaceous PM2.5 aerosol were investigated at a European background site at the edge of the Po Valley, in Northern Italy, during the period January - December 2007. Carbonaceous aerosol was described as the sum of eight source components: primary (1) and secondary (2) biomass burning organic carbon, biomass burning elemental carbon (3), primary (4) and secondary (5) fossil fuel burning organic carbon, fossil fuel burning elemental carbon (6), primary (7) and secondary (8) biogenic organic carbon. The concentration of each component was quantified using a set of macro tracers (organic carbon OC, elemental carbon EC, and levoglucosan), micro tracers (arabitol and mannitol), and 14C measurements. This was the first time that 14C measurements were performed on a long time series of data able to represent the entire annual cycle. This set of 6 tracers, together with assumed uncertainty ranges of the ratios of OC-to-EC, and the fraction of modern carbon in the 8 source categories, provides strong constraints to the source contributions to carbonaceous aerosol. The uncertainty of contributions was assessed with a Quasi-Monte Carlo (QMC) method accounting for the variability of OC and EC emission factors, and the uncertainty of reference fractions of modern carbon. During winter biomass burning composed 50% of the total carbon (TC) concentration, while in summer secondary biogenic OC accounted for 45% of TC. The contribution of primary biogenic aerosol particles was negligible during the entire year. Moreover, aerosol associated with fossil fuel burning represented 26% and 43% of TC in winter and summer, respectively. The comparison of source apportionment results in different urban and rural areas showed that the sampling site was mainly affected by local aerosol sources during winter and regional air masses from the nearby Po Valley in summer. This observation was further confirmed by back-trajectory analysis applying the Potential Source Contribution Function method to identify potential source regions. The contribution of secondary organic aerosol (SOA) to the organic mass (OM) was significant during the entire year. SOA accounted for 23% and 83% of OM during winter and summer, respectively. While the summer SOA was dominated by biogenic sources, winter SOA was mainly due to biomass and fossil fuel burning. This indicates that the oxidation of intermediate volatility organic compounds co-emitted with primary organics is a significant source of SOA, as suggested by recent model results and Aerosol Mass Spectrometer measurements in urban regions. Comparison with previous global model simulations, indicates a strong underestimate of wintertime primary aerosol emissions in this region.JRC.H.2-Air and Climat