A. Poupkou

A model for European Biogenic Volatile Organic Compound emissions: Software development and first validation

A grid-oriented Biogenic Emission Model (BEM) has been developed to calculate Non-Methane Volatile Organic Compound (NMVOC) emissions from vegetation in high spatial and temporal resolutions. The model allows the emissions calculation for any modeling domain covering Europe on the basis of: 1) the U.S. Geological Survey 1-km resolution land-use database, 2) a land-use specific, monthly isoprene, monoterpene and Other Volatile Organic Compound (OVOC) emission potentials and foliar biomass densities database, 3) temperature and solar radiation data provided by the mesoscale meteorological model MM5. The model was applied for Europe in 30-km spatial resolution for the year 2003. The European total emissions for 2003 consist of 33.0% isoprene, 25.5% monoterpenes and 41.5% OVOC. BEM results are compared with those from the well-documented global Model of Emissions of Gases and Aerosols from Nature (MEGAN). The BEM total emissions compare well with the MEGAN ones. In July 2003, the results of both models agree within a factor of 1.2 for total isoprene emissions and within a factor of 2 for total monoterpene emissions. The comparison of the spatial distributions of the July 2003 isoprene and monoterpene emissions calculated with BEM and MEGAN shows that, in the greater part of the study area, the differences are below the current uncertainty limit for the estimation of spatially-resolved biogenic VOC emissions in Europe being equal to about +/-600 kg km^-^2 month^-^1. Differences that are above this limit are found mainly in the eastern European countries for isoprene and in the Mediterranean countries for monoterpenes.

A GIS based anthropogenic PM10 emission inventory for Greece

An anthropogenic, chemically speciated PM10 emission inventory was compiled for Greece in 10 km spatial resolution. The inventory comprises of all anthropogenic particulate matter sources and it was compiled using a Geographical Information System (GIS) integrated with SQL programming language. Input data from the national and international databases were used for the calculation of spatially and temporally resolved emissions for the road transport and all the subsectors of the other mobile sources and machinery sector using top–down or bottom–up methodologies. Annual data from existing emission databases were also used and were temporally and spatially disaggregated using source relevant statistical data and high resolution maps. The sectoral emission totals are compared with other emission databases or studies conducted in the area. Total anthropogenic emissions in Greece were estimated to be 182 219 t for the base year 2003. The results indicate the industrial sector as the major PM10 emission source (39.9% contribution) with the major industrial units though to be situated inside the organised industrial areas of the country. The power generation sector (21.4%) is the second largest contributor in national level mostly derived from one specific industrial region at north. International cargo shipping activities (9.6%) is also an important source category for particles. Heat production and road transport are found to play a significant role inside the urban centres of the country.

The impact of anthropogenic and biogenic emissions on surface ozone concentrations in Istanbul.

Surface ozone concentrations at Istanbul during a summer episode in June 2008 were simulated using a high resolution and urban scale modeling system coupling MM5 and CMAQ models with a recently developed anthropogenic emission inventory for the region. Two sets of base runs were performed in order to investigate for the first time the impact of biogenic emissions on ozone concentrations in the Greater Istanbul Area (GIA). The first simulation was performed using only the anthropogenic emissions whereas the second simulation was performed using both anthropogenic and biogenic emissions. Biogenic NMVOC emissions were comparable with anthropogenic NMVOC emissions in terms of magnitude. The inclusion of biogenic emissions significantly improved the performance of the model, particularly in reproducing the low night time values as well as the temporal variation of ozone concentrations. Terpene emissions contributed significantly to the destruction of the ozone during nighttime. Biogenic NMVOCs emissions enhanced ozone concentrations in the downwind regions of GIA up to 25ppb. The VOC/NO(x) ratio almost doubled due to the addition of biogenic NMVOCs. Anthropogenic NO(x) and NMVOCs were perturbed by ±30% in another set of simulations to quantify the sensitivity of ozone concentrations to the precursor emissions in the region. The sensitivity runs, as along with the model-calculated ozone-to-reactive nitrogen ratios, pointed NO(x)-sensitive chemistry, particularly in the downwind areas. On the other hand, urban parts of the city responded more to changes in NO(x) due to very high anthropogenic emissions.

An Assessment of the Efficiency of Dust Regional Modelling to Predict Saharan Dust Transport Episodes

Aerosol levels at Mediterranean Basin are significantly affected by desert dust that is eroded in North Africa and is transported northwards. This study aims to assess the performance of the Dust REgional Atmospheric Model (BSC-DREAM8b) in the prediction of dust outbreaks near the surface in Eastern Mediterranean. For this purpose, model PM10 predictions covering a 7-year period and PM10 observations at five surface monitoring sites in Greece are used. A quantitative criterion is set to select the significant dust outbreaks defined as those when the predicted PM10 surface concentration exceeds 12 μg/m3. The analysis reveals that significant dust transport is usually observed for 1–3 consecutive days. Dust outbreak seasons are spring and summer, while some events are also forecasted in autumn. The seasonal variability of dust transport events is different at Finokalia, where the majority of events are observed in spring and winter. Dust contributes by 19–25% to the near surface observed PM10 levels, which can be increased to more than 50 μg/m3 during dust outbreaks, inducing violations of the air quality standards. Dust regional modeling can be regarded as a useful tool for air quality managers when assessing compliance with air quality limit values.

MOSESS: A New Emission Model for the Compilation of Model-Ready Emission Inventories—Application in a Coal Mining Area in Northern Greece

Over the last years, the capabilities of chemical transport models have been greatly improved and the need for more accurate emission data has increased as well. In the past, a number of emission models have been developed and present different functionalities and applications. The majority of these though cover very specific needs. This paper describes the development of a new emission model namely computer model for the construction of model-ready emission inventories (MOSESS) which is used to compile high-resolution emission inventories or improve existing ones, utilizing complex GIS techniques. The model aims in helping chemical modelers to obtain a better overview of their modeling application by having a comprehensive understanding of the emission input. MOSESS incorporates more than 70 different emission calculation methodologies, and it is capable of handling external emission databases (such as EMEP and EPER) from which emissions can be extracted. The temporal variation (annual/daily and diurnal processing), chemical speciation of NMVOCs and particles, vertical distribution and point source treatment, as well as the spatial disaggregation of emissions (utilizing numerous spatial proxies including high-resolution landuses) can help create model-ready emission inventories which can be used for contemporary modeling applications.

Enhanced surface ozone during the heat wave of 2013 in Yangtze River Delta region, China

Under the background of global warming, occurrence of heat waves has increased in most part of Europe, Asia and Australia along with enhanced ozone level. In this paper, observational air temperature and surface ozone in the Yangtze River Delta (YRD) region of China during summer of 2013, and the regional chemistry-climate model (RegCM-CHEM4) were applied to explore the relationship between heat wave and elevated ground-level ozone. Observations indicated that YRD experienced severe heat waves with maximum temperature up to 41.1°C, 6.1°C higher than the definition of heat wave in China, and can last for as long as 27days. Maximum ozone reached 160.5ppb, exceeding the national air quality standard (secondary level) as 74.7ppb. Moreover, ozone was found to increase at a rate of 4-5ppbK-1 within the temperature range of 28-38°C, but decrease by a rate of -1.3~-1.7ppbK-1 under extremely high temperature. A typical heat wave case (HW: 24/7-31/7) and non-heat wave case (NHW: 5/6-12/6) were selected to investigate the mechanism between heavy ozone and heat waves. It was found that chemical reactions play the most important role in ozone formation during HW days, which result in 12ppb ozone enhancement compared to NHW days. Chemical formation of ozone can be influenced by several factors. During heat waves, a more stagnant condition, controlled by anti-cyclone with sink airflow, led to less water vapor in YRD from south and contributed to less cloud cover, which favored a strong solar radiation environment and ozone significantly increasing. High temperature also slightly promote the effect of vertical turbulence and horizontal advection, which beneficial to ozone remove, but the magnitude is much smaller than chemical effect. Our study suggests that the chemical reaction will potentially lead to substantial elevated ozone in a warmer climate, which should be taken into account in future ozone related issues.

Climate change impact assessment of air pollution levels in bulgaria

The presented work is aiming at climate change impacts and vulnerability assessment in Bulgaria Climate change may affect exposures to air pollutants by affecting weather and thereby local and regional pollution concentrations Local weather patterns influence atmospheric chemical reactions and can also affect atmospheric transport and deposition processes. US EPA Models-3 System for a region with resolution of 10 km covering Bulgaria is exploited here The meteorological background is produced by the climatic version of ALADIN weather forecast system TNO emission inventory for 2000 is used The chemical boundary conditions are extracted from 50-km resolution runs over Europe made in Aristotle University of Thessaloniki, Greece Calculations for the period 1991-2000 are performed, results presented in a study For year 2000, some scenarios are run, results compared with measured data.

Evaluating the Performance of the RegCM-Chem4 Model in the Simulation of Ozone Levels During Heat Waves in China

China experienced major heat waves in summer 2013, being the worst the last 140 years in Eastern China. The RegCM-Chem4 climate-chemistry model was applied over China for the summer 2013 with a spatial resolution of 60 km and hourly temporal analysis. This study focuses on the examination of the RegCM-Chem4 performance in the simulation of ozone levels during two prolonged heat wave periods (24/07/2013–31/07/2013 and 07/08/2013–14/08/2013) and a non heat wave period (05/06/2013–12/06/2013) in Central and Eastern China. Near surface model results for ozone are compared with hourly observational data from 45 monitoring stations of the Chinese air quality network. The RegCM-Chem4 validation in the non-HW period presents good results. In August HW, the model underestimates the O3 values and variability, in line with RegCM-Chem4 temperature values underestimation in the same period, showing at almost all stations a performance that is not as good as that in the non-HW period. The performance of the model in the July HW requires further analysis; RegCM-Chem4 also underestimates the O3 levels and variability at almost all stations, however the model performance is not as good as that in the non-HW period only at a part of the AQ stations.

Higher Resolution Modeling of the PM10 Levels Over Istanbul for a Winter Episode

High winter-time PM10, sulfate, nitrate and ammonium levels in Istanbul were investigated using a high resolution WRF/CMAQ mesoscale model system. The results suggested that the system was capable of producing the magnitudes. PM10 levels calculated by the model underestimated the observations with an average of 10 % at Bogazici University sampling station, whereas an overestimation of 12 % is calculated for all stations. Base case results together with the sensitivity studies pointed significant contribution of local sources.

Study of the Impact of an Intense Biomass Burning Event on the Air Quality in the Eastern Mediterranean

Aim of this work is to study the impact of the intense forest fires that tookplace in Greece at the end of summer 2007 on the air quality in the Eastern Mediterranean. For this reason the meteorological model MM5 and the photochemical model CAMx are applied over the study area with 10 km spatial resolution. CAMx model is implemented for two emission scenarios; with and without biomass burning emissions. High spatial resolution wildfire emission data are used that are based on the Global Fire Emissions Database (GFED3). The CAMx chemical boundary conditions are taken from the TM4 global model. The nonradiative impact on the composition of the atmosphere and on environmental indices (e.g. Aggregate Risk Index) is quantified in regional scale. The impact of the atmospheric processes on the air pollution levels due to the biomass burning event is also studied giving more emphasis on the boundary layer. The intense biomass burning event in the Eastern Mediterranean at the end of August 2007 results in an enhancement of the CO, NOx and PM2.5 concentrations over almost all the study area, which can range from several times to two order of magnitude over the fire hot spots. The increases in O3 levels are less pronounced and are found mainly downwind the burnt areas. On the 25th August 2007, when fire counts in the study area are maximum, in the daytime boundary layer, the inclusion of biomass burning emissions results in a change of the chemical regime from O3 destruction to O3 production.