scholarly journals Estimating real driving emissions from MAX-DOAS measurements at the A60 motorway near Mainz, Germany

2020 ◽  
Author(s):  
Bianca Lauster ◽  
Steffen Dörner ◽  
Steffen Beirle ◽  
Sebastian Donner ◽  
Sergey Gromov ◽  
...  
Keyword(s):  
Nitrogen Oxides ◽  
Urban Areas ◽  
Road Traffic ◽  
Traffic Volume ◽  
In Situ Measurements ◽  
Wind Data ◽  
Nox Emissions ◽  
Dominant Source ◽  
Emission Standards

Abstract. In urban areas, road traffic is a dominant source of nitrogen oxides (NOx = NO + NO2). Although the emissions from individual vehicles are regulated by the European emission standards, real driving emissions often exceed these limits. In this study, two MAX-DOAS instruments on opposite sides of the motorway were used to measure the NO2 absorption caused by road traffic at the A60 motorway close to Mainz, Germany. In combination with wind data, the total NOx emissions for the occurring traffic volume can be estimated. We show that the measured emissions exceed the maximum expected emissions calculated from the European emission standards by a factor of 11 ± 7. One major advantage of the method used here is that from MAX-DOAS measurements the integrated NO2 concentration over the lowermost 2 to 3 km is determined. Thus, all emitted NO2 molecules are detected independent from their altitude and therefore the whole emission plume originating from the nearby motorway is captured by these measurements which is a key advantage compared to other approaches such as in-situ measurements.

scholarly journals Estimating real driving emissions from multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements at the A60 motorway near Mainz, Germany

2021 ◽  
Vol 14 (1) ◽  
pp. 769-783
Author(s):  
Bianca Lauster ◽  
Steffen Dörner ◽  
Steffen Beirle ◽  
Sebastian Donner ◽  
Sergey Gromov ◽  
...  
Keyword(s):  
Nitrogen Oxides ◽  
Optical Absorption ◽  
Absorption Spectroscopy ◽  
Urban Areas ◽  
Road Traffic ◽  
Differential Optical Absorption Spectroscopy ◽  
Optical Absorption Spectroscopy ◽  
Nox Emissions ◽  
Emission Standards

Abstract. In urban areas, road traffic is a dominant source of nitrogen oxides (NOx=NO+NO2). Although the emissions from individual vehicles are regulated by the European emission standards, real driving emissions often exceed these limits. In this study, two multi-axis differential optical absorption spectroscopy (MAX-DOAS) instruments on opposite sides of the motorway were used to measure the NO2 absorption caused by road traffic at the A60 motorway close to Mainz, Germany. In combination with wind data, the total NOx emissions for the occurring traffic volume can be estimated. Hereto, the ozone-dependent photochemical equilibrium between NO and NO2 is considered. We show that for 10 May 2019 the measured emissions exceed the maximum expected emissions calculated from the European emission standards for standardised test cycles by a factor of 11±7. One major advantage of the method used here is that MAX-DOAS measurements are very sensitive to the integrated NO2 concentration close to the surface. Thus, all emitted NO2 molecules are detected independently from their altitude, and therefore the whole emission plume originating from the nearby motorway is captured, which is a key advantage compared to other approaches such as in situ measurements.

scholarly journals Evaluation of modeling NO<sub>2</sub> concentrations driven by satellite-derived and bottom-up emission inventories using in situ measurements over China

2018 ◽  
Vol 18 (6) ◽  
pp. 4171-4186 ◽  
Author(s):  
Fei Liu ◽  
Ronald J. van der A ◽  
Henk Eskes ◽  
Jieying Ding ◽  
Bas Mijling
Keyword(s):  
Spatial Correlation ◽  
Rural Areas ◽  
Urban Areas ◽  
Transport Model ◽  
Chemical Transport ◽  
In Situ Measurements ◽  
Nox Emissions ◽  
Emission Inventories ◽  
Bottom Up

Abstract. Chemical transport models together with emission inventories are widely used to simulate NO2 concentrations over China, but validation of the simulations with in situ measurements has been extremely limited. Here we use ground measurements obtained from the air quality monitoring network recently developed by the Ministry of Environmental Protection of China to validate modeling surface NO2 concentrations from the CHIMERE regional chemical transport model driven by the satellite-derived DECSO and the bottom-up MIX emission inventories. We applied a correction factor to the observations to account for the interferences of other oxidized nitrogen compounds (NOz), based on the modeled ratio of NO2 to NOz. The model accurately reproduces the spatial variability in NO2 from in situ measurements, with a spatial correlation coefficient of over 0.7 for simulations based on both inventories. A negative and positive bias is found for the simulation with the DECSO (slope  =  0.74 and 0.64 for the daily mean and daytime only) and the MIX (slope  =  1.3 and 1.1) inventories, respectively, suggesting an underestimation and overestimation of NOx emissions from corresponding inventories. The bias between observed and modeled concentrations is reduced, with the slope dropping from 1.3 to 1.0 when the spatial distribution of NOx emissions in the DECSO inventory is applied as the spatial proxy for the MIX inventory, which suggests an improvement of the distribution of emissions between urban and suburban or rural areas in the DECSO inventory compared to that used in the bottom-up inventory. A rough estimate indicates that the observed concentrations, from sites predominantly placed in the populated urban areas, may be 10–40 % higher than the corresponding model grid cell mean. This reduces the estimate of the negative bias of the DECSO-based simulation to the range of −30 to 0 % on average and more firmly establishes that the MIX inventory is biased high over major cities. The performance of the model is comparable over seasons, with a slightly worse spatial correlation in summer due to the difficulties in resolving the more active NOx photochemistry and larger concentration gradients in summer by the model. In addition, the model well captures the daytime diurnal cycle but shows more significant disagreement between simulations and measurements during nighttime, which likely produces a positive model bias of about 15 % in the daily mean concentrations. This is most likely related to the uncertainty in vertical mixing in the model at night.

scholarly journals Evaluation of modelling NO<sub>2</sub> concentrations driven by satellite-derived and bottom-up emission inventories using in-situ measurements over China

2017 ◽  
Author(s):  
Fei Liu ◽  
Ronald J. van der A ◽  
Henk Eskes ◽  
Jieying Ding ◽  
Bas Mijling
Keyword(s):  
Spatial Correlation ◽  
Rural Areas ◽  
Urban Areas ◽  
Transport Model ◽  
Chemical Transport ◽  
In Situ Measurements ◽  
Nox Emissions ◽  
Emission Inventories ◽  
Bottom Up

Abstract. Chemical transport models together with emission inventories are widely used to simulate NO2 concentrations over China, but validation of the simulations with in situ measurements has been extremely limited. Here we use ground measurements obtained from the air quality monitoring network recently developed by the Ministry of Environmental Protection of China to validate modelling surface NO2 concentrations from the CHIMERE regional chemical-transport model driven by the satellite-derived DECSO and the bottom-up MIX emission inventories. We applied a correction factor to the observations to account for the interferences of other oxidized nitrogen compounds (NOz), based on the modelled ratio of NO2 to NOz. The model accurately reproduces the spatial variability of NO2 from in-situ measurements, with a spatial correlation coefficient of over 0.7 for simulations based on both inventories. A negative and positive bias is found for the simulation with the DECSO (slope = 0.74/0.64 for the daily-mean/daytime only) and the MIX (slope = 1.3/1.1) inventory respectively, suggesting an underestimation and overestimation of NOx emissions from corresponding inventories. The bias between observed and modelled concentrations is reduced with the slope dropping from 1.3 to 1.0 when the spatial distribution of NOx emissions in the DECSO inventory is applied as the spatial proxy for the MIX inventory, which suggests an improvement of the distribution of emissions between urban and suburban/rural areas in the DECSO inventory compared to that used in the bottom-up inventory. A rough estimate indicates that the observed concentrations, from sites predominantly placed in the populated urban areas, may be 10–40 % higher than the corresponding model grid-cell mean. This reduces the estimate of the negative bias of the DECSO based simulation to the range of −30 % to 0 % on average, and establishes more firmly that the MIX inventory is biased high over major cities. The performance of the model is comparable over seasons, with a slightly worse spatial correlation in summer, due to the difficulties in resolving the more active NOx photochemistry and larger concentration gradients in summer by the model. In addition, the model well captures the daytime diurnal cycle, but shows more significant disagreement between simulations and measurements during night time, which likely produces a positive model bias of about 15 % in the daily mean concentrations. This is most likely related to the uncertainty in vertical mixing in the model at night.

Considerations on Ambient Levels of Ozone Concentrations and Relationship with NOx in an Urban Environment

2017 ◽  
Vol 68 (4) ◽  
pp. 824-829
Author(s):  
Cornel Ianache ◽  
Laurentiu Predescu ◽  
Mirela Predescu ◽  
Dumitru Dumitru
Keyword(s):  
Nitrogen Oxides ◽  
Urban Areas ◽  
Road Traffic ◽  
Temporal Distribution ◽  
Ground Level ◽  
Distinct Pattern ◽  
Weekend Effect ◽  
Monitoring Site ◽  
Ground Level Ozone ◽  
Ozone Concentrations

The serious air pollution problem has determined public concerns, worldwide. One of the main challenges for countries all over the world is caused by the elevated levels of ground-level ozone (O3) concentrations and its anthropogenic precursors. Ploiesti city, as one of the major urban area of Romania, is facing the same situation. This research aims to investigate spatial and temporal distribution characteristics of O3 in relationship with nitrogen oxides (NOx) using statistical analysis methods. Hourly O3 and NOx measurements were collected during 2014 year in Ploiesti. The results obtained showed that the ozone spatial distribution was non-normal for each month in 2014. The diurnal cycle of ground-level ozone concentrations showed a mid-day peak, while NOx diurnal variations presented 2 daily peaks, one in the morning (7:00 a.m.) and one in the afternoon (between 5:00 and 7:00 p.m.). In addition, it was observed a distinct pattern of weekly variations for O3 and NOx. Like in many other urban areas, the results indicated the presence of the �ozone weekend effect� in Ploiesti during the 2014 year, ozone concentrations being slightly higher on weekends compared to weekdays. For the same monitoring site, the nitrogen oxides were less prevalent on Saturdays and Sundays, probably due to reducing of road traffic and other pollution-generating activities on weekends than during the week.

scholarly journals A Study of UVER in Santiago, Chile Based on Long-Term In Situ Measurements (Five Years) and Empirical Modelling

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 368
Author(s):  
Lisdelys González-Rodríguez ◽  
Amauri Pereira de Oliveira ◽  
Lien Rodríguez-López ◽  
Jorge Rosas ◽  
David Contreras ◽  
...  
Keyword(s):  
Urban Areas ◽  
Solar Spectrum ◽  
Sun Exposure ◽  
Great Accuracy ◽  
In Situ Measurements ◽  
Uv Index ◽  
Empirical Modelling ◽  
The People

Ultraviolet radiation is a highly energetic component of the solar spectrum that needs to be monitored because is harmful to life on Earth, especially in areas where the ozone layer has been depleted, like Chile. This work is the first to address the long-term (five-year) behaviour of ultraviolet erythemal radiation (UVER) in Santiago, Chile (33.5° S, 70.7° W, 500 m) using in situ measurements and empirical modelling. Observations indicate that to alert the people on the risks of UVER overexposure, it is necessary to use, in addition to the currently available UV index (UVI), three more erythema indices: standard erythemal doses (SEDs), minimum erythemal doses (MEDs), and sun exposure time (tery). The combination of UVI, SEDs, MEDs, and tery shows that in Santiago, individuals with skin types III and IV are exposed to harmfully high UVER doses for 46% of the time that UVI indicates is safe. Empirical models predicted hourly and daily values UVER in Santiago with great accuracy and can be applied to other Chilean urban areas with similar climate. This research inspires future advances in reconstructing large datasets to analyse the UVER in Central Chile, its trends, and its changes.

Modelling rain heterogeneities within an urban neighbourhood

2021 ◽  
Author(s):  
Karolin S. Ferner ◽  
K. Heinke Schlünzen ◽  
Marita Boettcher
Keyword(s):  
Wind Speed ◽  
Urban Areas ◽  
Climate Model ◽  
Numerical Models ◽  
Urban Climate ◽  
Cloud Microphysics ◽  
In Situ Measurements ◽  
Small Scale ◽  
Atmospheric Processes

&lt;p&gt;Urbanisation locally modifies the regional climate: an urban climate develops. For example, the average wind speed in cities is reduced, while the gustiness is increased. Buildings induce vertical winds, which influence the falling of rain. All these processes lead to heterogeneous patterns of rain at ground and on building surfaces. The small-scale spatial rain heterogeneities may cause discomfort for people. Moreover, non-uniform wetting of buildings affects their hydrothermal performance and durability of their facades.&lt;/p&gt;&lt;p&gt;Measuring rain heterogeneities between buildings is, however, nearly impossible. Building induced wind gusts negatively influence the representativeness of in-situ measurements, especially in densely urbanised areas. Weather radars are usually too coarse and, more importantly, require an unobstructed view over the domain and thus do not measure ground precipitation in urban areas. Consequently, researchers turn to numerical modelling in order to investigate small-scale precipitation heterogeneities between buildings.&lt;/p&gt;&lt;p&gt;In building science, numerical models are used to investigate rain heterogeneities typically focussing on single buildings and vertical facades. Only few studies were performed for more than a single building or with inclusion of atmospheric processes such as radiation or condensation. In meteorology, increasing computational power now allows the use of small-scale obstacle-resolving models resolving atmospheric processes while covering neighbourhoods.&lt;/p&gt;&lt;p&gt;In order to assess rain heterogeneities between buildings we extended the micro-scale and obstacle-resolving transport- and stream model MITRAS (Salim et al. 2019). The same cloud microphysics parameterisation as in its mesoscale sister model METRAS (Schl&amp;#252;nzen et al., 2018) was applied and boundary conditions for cloud and rain water content at obstacle surfaces were introduced. MITRAS results are checked for plausibility using radar and in-situ measurements (Ferner et al., 2021). To our knowledge MITRAS is the first numerical urban climate model that includes rain and simulates corresponding processes.&lt;/p&gt;&lt;p&gt;Model simulations were initialised for various wind speeds and mesoscale rain rates to assess their influence on the heterogeneity of falling rain in a domain of 1.9 x 1.7 km&amp;#178; around Hamburg City Hall. We investigated how wind speed or mesoscale rain rate influence the precipitation patterns at ground and at roof level. Based on these results we assessed the height dependence of precipitation. First analyses show that higher buildings receive more rain on their roofs than lower buildings; the results will be presented in detail in our talk.&lt;/p&gt;&lt;p&gt;Ferner, K.S., Boettcher, M., Schl&amp;#252;nzen, K.H. (2021): Modelling the heterogeneity of rain in an urban neighbourhood. Publication in preparation&lt;/p&gt;&lt;p&gt;Salim, M.H., Schl&amp;#252;nzen, K.H., Grawe, D., Boettcher, M., Gierisch, A.M.U., Fock B.H. (2018): The microscale obstacle-resolving meteorological model MITRAS v2.0: model theory. Geosci. Model Dev., 11, 3427&amp;#8211;3445, https://doi.org/10.5194/gmd-11-3427-2018.&lt;/p&gt;&lt;p&gt;Schl&amp;#252;nzen, K.H., Boettcher, M., Fock, B.H., Gierisch, A.M.U., Grawe, D., and Salim, M. (2018): Scientific Documentation of the Multiscale Model System M-SYS. Meteorological Institute, Universit&amp;#228;t Hamburg. MEMI Technical Report 4&lt;/p&gt;

scholarly journals Assessment of road traffic performance of the Tsunami evacuation road in Padang Municipality area based on the traffic volume simulation approach

2020 ◽  
Vol 156 ◽  
pp. 04008
Author(s):  
Yossyafra Yossyafra ◽  
Nurhuda Fitri ◽  
Rahmat Punama Sidhi ◽  
Yosritzal Yosritzal ◽  
Deni Irda Mazni
Keyword(s):  
Land Use ◽  
Traffic Congestion ◽  
Urban Areas ◽  
Road Traffic ◽  
Traffic Volume ◽  
Disaster Mitigation ◽  
Degree Of Saturation ◽  
Vehicle Ownership ◽  
The Road ◽  
Tsunami Disaster

There are many cities on the west coast of the Sumatra, which are at high risk of the Tsunami disaster. Regional Regulations on Regional Spatial Planning for each City/ Regency have compiled disaster mitigation by constructing several evacuation roads. This study wants to illustrate: what are the volume of traffic generation and road performance, if there is a Tsunami disaster. The simulation is developed by predicting traffic volume based on parameters, population density, vehicle ownership, land use, and activities in the area around the road. The assessment was carried out on two tsunami evacuation roads in the city of Padang, West Sumatra Province. The results show that the highest traffic volume occurred in the period from 06.30 a.m until 3:00 p.m., during school activities. One of the roads will not be able to accommodate the volume of traffic during a disaster, due to significant traffic congestion. This study shows that: (1) the period of activity and land use are two main parameters, which must be considered in designing tsunami evacuation roads, (2) The degree of saturation ratio and the ratio between the capacity of sections of Tsunami evacuation routes can be proposed as a parameter for assessing the performance of Tsunami evacuation roads in urban areas.

scholarly journals Twenty years of ambient observations of nitrogen oxides and specified hydrocarbons in air masses dominated by traffic emissions in Germany

2016 ◽  
Vol 189 ◽  
pp. 407-437 ◽  
Author(s):  
Christian Ehlers ◽  
Dieter Klemp ◽  
Franz Rohrer ◽  
Djuro Mihelcic ◽  
Robert Wegener ◽  
...  
Keyword(s):  
Nitrogen Oxides ◽  
Urban Areas ◽  
Road Traffic ◽  
Traffic Emissions ◽  
Ozone Production ◽  
Hydrocarbon Mixture ◽  
Oh Radicals ◽  
Time Period ◽  
Oxide Removal ◽  
German Cities

The analysis of the individual composition of hydrocarbon (VOC) mixtures enables us to transform observed VOC-concentrations into their respective total VOC-reactivity versus OH radicals (RVOC = Σ(kOH+VOCi × [VOCi])). This is particularly useful because local ozone production essentially depends on this single parameter rather than on the details of the underlying hydrocarbon mixture (Klemp et al., Schriften des Forschungszentrums Jülich, Energy & Environment, 2012, 21). The VOC composition also enables us to pin down the major emission source of hydrocarbons in urban areas to be petrol cars with temporarily reduced catalyst efficiency (the so-called cold-start situation) whereas the source of nitrogen oxides (NOx = NO + NO2) is expected to be nowadays dominated by diesel cars. The observations in the vicinity of main roads in German cities show a decrease in the ratio of OH reactivities of VOC and NO2 (RVOC/RNO2) by a factor of 7.5 over the time period 1994–2014. This is larger than the expected decrease of a factor of 2.9 taking estimated trends of VOC and NOx traffic emissions in Germany (Umweltbundesamt Deutschland, National Trend Tables for the German Atmospheric Emission Reporting, 2015), during this time period. The observed reduction in the RVOC/RNO2 ratio leads to a drastic decrease in local ozone production driven by the reduction in hydrocarbons. The analysis reveals that the overall reduction of ozone production benefits from the low decrease of NOx emissions from road traffic which is a consequence of the eventual absence of catalytic converters for nitrogen oxide removal in diesel cars up to now.

scholarly journals Impact of pollutant emission from motor vehicles on air quality in a city agglomeration

2019 ◽  
Vol 177 (2) ◽  
pp. 7-11
Author(s):  
Zdzisław CHŁOPEK ◽  
Jakub LASOCKI ◽  
Katarzyna STRZAŁKOWSKA ◽  
Dagna ZAKRZEWSKA
Keyword(s):  
Particulate Matter ◽  
Air Quality ◽  
Nitrogen Oxides ◽  
Organic Compounds ◽  
Urban Areas ◽  
Road Traffic ◽  
Strong Dependence ◽  
Motor Vehicles ◽  
Pollutant Emission ◽  
Emission Data

In the large urban areas, in middle latitudes, as in case of Poland, the cause of poor air quality is immission: in winter particulate matter PM10 and PM2.5, in summer – ozone and nitrogen oxides (or nitrogen dioxide). In the whole country, road transport is significantly responsible for the emission of nitrogen oxides (30%), carbon monoxide (20%) and less for emission of particulate matter (a few percent). In the case of other pollutants, the emission of non-metallic organic compounds is less than 10% (including polycyclic organic compounds – just over 0.5%), and sulfur oxides – only 0.03%! To analyze impact of automotive industry on air quality, pollutant emission data from two stations in Krakow were selected. These stations are known for poor air quality – the stations are: Dietla Street – with a high level of traffic and Kurdwanów – place located far from traffic routes. It was found that other objects than automotive vehicles are the dominant source of dust. These are industrial sources and – above all – energy sources, especially individual heating installations. Particularly large dust pollution occurs in winter and it is not always in areas with intense traffic. There was a strong dependence between immission of pollutants and road traffic, however, this dependence is not dominant in assessing the risk of air quality in urban agglomerations.

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