Spatial extension of nucleating air masses in the Carpathian Basin

Abstract. Particle number size distributions were measured by differential mobility particle sizer in the diameter range of 6–1000 nm in the near-city background and city centre of Budapest continuously for two years. The city is situated in the middle part of the Carpathian Basin, which is a topographically discrete unit in the southeastern part of central Europe. Yearly mean nucleation frequencies and uncertainties for the near-city background and city centre were (28 + 6/−4) % and (27 + 9/−4) %, respectively. The total numbers of days with continuous and uninterrupted growth process were 43 and 31, respectively. These events and their properties were utilised to investigate the spatial scale of the nucleation in the basin, and whether there are any specific trajectories for the nucleating air masses. Local wind speed and direction data indicated that there seem to be differences between the nucleation and growth intervals and non-nucleation days. For further analysis, backward trajectories were generated by a simple air parcel trajectory model. Start and end time parameters of the nucleation and an end time parameter of the particle growth were derived by a standardised procedure based on examining the channel contents of the contour plots. These parameters were used to specify a segment on each backward trajectory that is associated with the nucleating air mass. The results indicated that regional nucleation happened in the continental boundary layer mostly in the Carpathian Basin but that the most distant trajectories originated outside of the basin. The nucleating air masses were predominantly associated with NW and SE geographical sectors, and some of them were also related to larger forested territories. The results also emphasised indirectly that the regional new particle formation and growth phenomena observable at the fixed location often expand to the bulk of the Carpathian Basin.

Download Full-text

Source areas and trajectories of nucleating air masses within and near the Carpathian Basin

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-14-9225-2014 ◽

2014 ◽

Vol 14 (7) ◽

pp. 9225-9247

Author(s):

Z. Németh ◽

I. Salma

Keyword(s):

Particle Growth ◽

Middle Part ◽

Carpathian Basin ◽

City Centre ◽

Air Mass ◽

Air Masses ◽

Source Areas ◽

Growth Phenomenon ◽

Contour Plots ◽

Particle Sizer

Abstract. Particle number size distributions were measured by differential mobility particle sizer in the diameter range of 6–1000 nm in the near-city background and city centre of Budapest continuously for two years. The city is situated in the middle part of the Carpathian Basin, which is a topographically discrete unit in the southeast Central Europe. Yearly mean nucleation frequencies and uncertainties for the near-city background and city centre were (28+6/−4) % and (27+9/−4) %, respectively. Total numbers of days with continuous and uninterrupted growth process were 43 and 31, respectively. These events and their properties were utilised to investigate if there are any specific tracks and/or separable source regions for the nucleating air masses within or near the basin. Local wind speed and direction data indicated that there seem to be differences between the nucleation and growth intervals and non-nucleation days. For further analysis, backward trajectories were generated by a simple air parcel trajectory model. Start and end time parameters of the nucleation, and end time parameter of the particle growth were derived by a standardized procedure based on examining the channel contents of the contour plots. These parameters were used to specify a segment on each air mass trajectory that is associated with the track of the nucleating air mass. The results indicated that the nucleation events happened in the continental boundary layer mostly within the Carpathian Basin but the most distant trajectories originated outside of the basin. The tracks of the nucleating air masses were predominantly associated with NW and SE geographical fields, while the source areas that could be separated were frequently situated in the NW and NE quarters. Many of them were within or close to large forested territories. The results also emphasize that the new particle formation and growth phenomenon that occurs in the region influences larger territories than the Carpathian Basin.

Download Full-text

Analysis of granulometric dust accumulating in supply and exhaust ventilation filters

E3S Web of Conferences ◽

10.1051/e3sconf/20184400030 ◽

2018 ◽

Vol 44 ◽

pp. 00030

Author(s):

Bogdan Derbiszewski ◽

Anna Kurek

Keyword(s):

Diffraction Theory ◽

Particle Size Analysis ◽

City Centre ◽

Size Analysis ◽

Exhaust Ventilation ◽

Air Supply ◽

Air Handling Units ◽

Different Seasons ◽

Particle Sizer ◽

The City

The research aim was to analyse and compare the composition of granulometric dust which accumulates in air filters located in central air handling units supporting the production rooms and at the same time the degree and a kind of contamination fraction of atmospheric air in a part of Wrocław situated outside the city centre. Samples were taken in different seasons of the year, such as March and October. The size of pollution particles extracted from ventilation filters was measured with the use of ANALYSETTE 22MicroTec plus laser particle sizer produced by FRITSCH. The results of measurements were generated with MaScontrol software for particle size analysis. In computing research results, the Fraunhofer diffraction theory was used. The comparison of the examined air particles’ size in an air supply canal allowed to determine the outside air dust size in Szczepin district on Długa street in Wrocław. Moreover, the influence of the year season on the size of contaminants accumulating in filters was also determined in the course of research works.

Download Full-text

Fossil fuel combustion, biomass burning and biogenic sources of fine carbonaceous aerosol in the Carpathian Basin

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-4295-2020 ◽

2020 ◽

Vol 20 (7) ◽

pp. 4295-4312 ◽

Cited By ~ 2

Author(s):

Imre Salma ◽

Anikó Vasanits-Zsigrai ◽

Attila Machon ◽

Tamás Varga ◽

István Major ◽

...

Keyword(s):

Biomass Burning ◽

Fossil Fuel ◽

Fuel Combustion ◽

Carpathian Basin ◽

Total Carbon ◽

Carbonaceous Aerosol ◽

City Centre ◽

Fossil Fuel Combustion ◽

Regional Background ◽

The City

Abstract. Fine-fraction aerosol samples were collected, and air pollutants and meteorological properties were measured in situ in the regional background environment of the Carpathian Basin, a suburban area and central part of its largest city, Budapest, in each season for a 1-year-long time interval. The samples were analysed for PM2.5 mass, organic carbon (OC), elemental carbon (EC), water-soluble OC (WSOC), radiocarbon, levoglucosan (LVG) and its stereoisomers, and some chemical elements. Carbonaceous aerosol species made up 36 % of the PM2.5 mass, with a modest seasonal variation and with a slightly increasing tendency from the regional background to the city centre (from 32 % to 39 %). A coupled radiocarbon-LVG marker method was applied to apportion the total carbon (TC = OC + EC) into contributions of EC and OC from fossil fuel (FF) combustion (ECFF and OCFF, respectively), EC and OC from biomass burning (BB) (ECBB and OCBB, respectively), and OC from biogenic sources (OCBIO). Fossil fuel combustion showed rather constant daily or monthly mean contributions (of 35 %) to the TC in the whole year in all atmospheric environments, while the daily contributions of BB and biogenic sources changed radically (from <2 % up to 70 %–85 %) at all locations and over the years. In October, the three major sources contributed equally to the TC in all environments. In January, it was the BB that was the major source, with a share of 70 % at all sites. The contributions from biogenic sources in January were the smallest. In April, FF combustion and biogenic sources were the largest two contributors at all locations with typical shares of 45 %–50 % each. In July, biogenic sources became the major source type with a monotonically increasing tendency (from 56 % to 72 %) from the city centre to the regional background. The share of BB was hardly quantifiable in July. The ECFF made up more than 90 % of EC in April and July, while in October and January, the contributions of ECBB were considerable. Biomass burning in winter and autumn offers the largest and most considerable potential for improving the air quality in cities as well as in rural areas of the Carpathian Basin.

Download Full-text

Consequences of dynamic and timing properties of new aerosol particle formation and consecutive growth events

10.5194/acp-2018-918 ◽

2018 ◽

Author(s):

Imre Salma ◽

Zoltán Németh

Keyword(s):

Dynamic Properties ◽

Meteorological Data ◽

Particle Diameter ◽

Chemical Species ◽

Particle Growth ◽

Particle Formation ◽

City Centre ◽

Timing Properties ◽

The City ◽

Event Occurrence

Abstract. Dynamic properties, i.e. particle formation rate J6 and particle diameter growth rate GR10, and timing properties, i.e. starting time (t1) and duration time interval (Δt) of 247 quantifiable (class 1A) atmospheric new particle formation (NPF) and consecutive particle diameter growth events identified in the city centre and near-city background of Budapest over 6 full measurement years together with related gas-phase H2SO4 proxy, condensation sink (CS) of vapours, basic meteorological data and concentrations of criteria pollutant gases were derived, evaluated, discussed and interpreted. In the city centre, nucleation ordinarily starts at 09:15 UTC+1, and it is maintained for approximately 3 h. The NPF and growth events produce 4.6 aerosol particles with a diameter of 6 nm in 1 cm3 of air in 1 s, and cause the particles with a diameter of 10 nm to grow with a typical rate of 7.3 nm h−1. Nucleation starts approximately 1 h earlier in the near-city background, it shows substantially smaller J6 (with a median of 2.0 cm−3 s−1) and GR10 values (with a median of 5.0 nm h−1), while the duration of nucleation is similar to that in the centre. Monthly distributions of the dynamic properties and daily maximum H2SO4 proxy do not follow the mean monthly pattern of the event occurrence frequency. The factors that control the event occurrence and that govern the intensity of particle formation and growth are not directly linked. Condensing atmospheric chemical species and/or their processes in the city centre seem to contribute equally to new particle formation and particle growth. In the near-city background, however, chemical compounds available and their processes power particle growth more than particle formation. There is a minimum growth rate of approximately 1.8 nm h−1 that is required for nucleated particles to reach the lower end of the diameter interval measured (6 nm) under the actual/local conditions. Monthly distributions and relationships among the properties mentioned provided several indirect evidence that chemical species other than H2SO4 largely influence the particle growth and possibly atmospheric NPF process as well. The J6, GR10 and Δt can be described by log-normal distribution. Most of the extreme dynamic properties could not be explained by H2SO4 proxy, CS, meteorological data or pollutant gas concentrations. Approximately 40 % of the NPF and growth events exhibited broad beginning, which can be an urban feature. For 9 % of all cases, it was feasible to calculate 2 separate sets of dynamic properties. The later onset frequently shows more intensive particle formation and growth than the first onset by a typical factor of approximately 1.4. The first event is of regional type, while the second event, superimposed on the first, is often associated with sub-regional, thus urban NPF and growth process.

Download Full-text

Analysis of particle size distribution changes between three measurement sites in Northern Scandinavia

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-9401-2013 ◽

2013 ◽

Vol 13 (4) ◽

pp. 9401-9442 ◽

Cited By ~ 1

Author(s):

R. Väänänen ◽

E.-M. Kyrö ◽

T. Nieminen ◽

N. Kivekäs ◽

H. Junninen ◽

...

Keyword(s):

Particle Size ◽

Size Distribution ◽

Aerosol Particle ◽

Particle Growth ◽

Particle Formation ◽

Aerosol Size Distribution ◽

New Particle Formation ◽

Air Masses ◽

Aerosol Dynamics ◽

Particle Sizer

Abstract. We investigated atmospheric aerosol particle dynamics in a boreal forest zone in Northern Scandinavia. We used aerosol size distribution data measured with either a Differential Mobility Particle Sizer (DMPS) or Scanning Mobility Particle Sizer (SMPS) at three stations (Värriö, Pallas and Abisko), and combined these data with the HYSPLIT air mass trajectory analysis. We compared three approaches: analysis of new particle formation events, investigation of air masses transport from the ocean to individual stations with different over-land transport times, and analysis of changes in aerosol particle size distributions during the air masses transport from one measurement station to another. Aitken mode particles were found to have an apparent average growth rate of 0.6–0.7 nm h−1 when the air masses travelled over land. Particle growth rates during the NPF events were 3–6 times higher than the apparent particle growth. When comparing aerosol dynamics between the different stations for different over-land transport times, no major differences were found except that in Abisko the new particle formation events were observed to take place in air masses having shorter over-land times than at the other stations. We speculate that this is related to the meteorological differences along the paths of air masses caused by the land surface topology. When comparing between air masses travelling the east-to-west direction to those traveling the west-to-east directions, clear differences in the aerosol dynamics were seen. Our results suggest that the condensation growth has an important role in aerosol dynamics also when new particle formation is not evident.

Download Full-text

Analysis of particle size distribution changes between three measurement sites in northern Scandinavia

Atmospheric Chemistry and Physics ◽

10.5194/acp-13-11887-2013 ◽

2013 ◽

Vol 13 (23) ◽

pp. 11887-11903 ◽

Cited By ~ 16

Author(s):

R. Väänänen ◽

E.-M. Kyrö ◽

T. Nieminen ◽

N. Kivekäs ◽

H. Junninen ◽

...

Keyword(s):

Mass Transport ◽

Aerosol Particle ◽

Growth Rates ◽

Particle Number ◽

Particle Growth ◽

Size Distributions ◽

Air Mass ◽

Air Masses ◽

Aerosol Dynamics ◽

Particle Sizer

Abstract. We investigated atmospheric aerosol particle dynamics in a boreal forest zone in northern Scandinavia. We used aerosol number size distribution data measured with either a differential mobility particle sizer (DMPS) or scanning mobility particle sizer (SMPS) at three stations (Värriö, Pallas and Abisko), and combined these data with the HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) air mass trajectory analysis. We compared three approaches: analysis of new particle formation events, investigation of aerosol particle number size distributions during the air mass transport from the ocean to individual stations with different overland transport times, and analysis of changes in aerosol particle number size distributions during the air mass transport from one measurement station to another. Aitken-mode particles were found to have apparent average growth rates of 0.6–0.7 nm h−1 when the air masses traveled over land. Particle growth rates during the new particle formation (NPF) events were 3–6 times higher than the apparent particle growth during the summer period. When comparing aerosol dynamics for different overland transport times between the different stations, no major differences were found, except that in Abisko the NPF events were observed to take place in air masses with shorter overland times than at the other stations. We speculate that this is related to the meteorological differences along the paths of air masses caused by the land surface topology. When comparing air masses traveling in an east-to-west direction with those traveling in a west-to-east direction, clear differences in the aerosol dynamics were seen. Our results suggest that the condensation growth has an important role in aerosol dynamics even when NPF is not evident.

Download Full-text

Restricting Traffic into the City Centre: Has Madrid Central Been Effective to Reduce NO 2 Levels?

SSRN Electronic Journal ◽

10.2139/ssrn.3495440 ◽

2019 ◽

Cited By ~ 3

Author(s):

Rafael Salas ◽

María José Pérez Villadóniga ◽

Juan Prieto Rodríguez ◽

Ana Russo

Keyword(s):

City Centre ◽

The City

Download Full-text

What Makes a City Bikeable? A Study of Intercity and Intracity Patterns of Bicycle Ridership using Mobike Big Data Records

Built Environment ◽

10.2148/benv.46.1.55 ◽

2020 ◽

Vol 46 (1) ◽

pp. 55-75

Author(s):

Ying Long ◽

Jianting Zhao

Keyword(s):

Big Data ◽

Average Distance ◽

Policy Implications ◽

Rating System ◽

City Centre ◽

Average Score ◽

Policy Makers ◽

Usage Frequency ◽

Share Data ◽

The City

This paper examines how mass ridership data can help describe cities from the bikers' perspective. We explore the possibility of using the data to reveal general bikeability patterns in 202 major Chinese cities. This process is conducted by constructing a bikeability rating system, the Mobike Riding Index (MRI), to measure bikeability in terms of usage frequency and the built environment. We first investigated mass ridership data and relevant supporting data; we then established the MRI framework and calculated MRI scores accordingly. This study finds that people tend to ride shared bikes at speeds close to 10 km/h for an average distance of 2 km roughly three times a day. The MRI results show that at the street level, the weekday and weekend MRI distributions are analogous, with an average score of 49.8 (range 0–100). At the township level, high-scoring townships are those close to the city centre; at the city level, the MRI is unevenly distributed, with high-MRI cities along the southern coastline or in the middle inland area. These patterns have policy implications for urban planners and policy-makers. This is the first and largest-scale study to incorporate mobile bike-share data into bikeability measurements, thus laying the groundwork for further research.

Download Full-text

AnANN Model Trained on Regional Data in the Prediction of Particular Weather Conditions

Applied Sciences ◽

10.3390/app11114757 ◽

2021 ◽

Vol 11 (11) ◽

pp. 4757

Author(s):

Aleksandra Bączkiewicz ◽

Jarosław Wątróbski ◽

Wojciech Sałabun ◽

Joanna Kołodziejczyk

Keyword(s):

Atmospheric Pressure ◽

Real Life ◽

Real Data ◽

Weather Conditions ◽

Maximum Temperature ◽

Air Masses ◽

Weather Forecasts ◽

Life Problems ◽

The World ◽

The City

Artificial Neural Networks (ANNs) have proven to be a powerful tool for solving a wide variety of real-life problems. The possibility of using them for forecasting phenomena occurring in nature, especially weather indicators, has been widely discussed. However, the various areas of the world differ in terms of their difficulty and ability in preparing accurate weather forecasts. Poland lies in a zone with a moderate transition climate, which is characterized by seasonality and the inflow of many types of air masses from different directions, which, combined with the compound terrain, causes climate variability and makes it difficult to accurately predict the weather. For this reason, it is necessary to adapt the model to the prediction of weather conditions and verify its effectiveness on real data. The principal aim of this study is to present the use of a regressive model based on a unidirectional multilayer neural network, also called a Multilayer Perceptron (MLP), to predict selected weather indicators for the city of Szczecin in Poland. The forecast of the model we implemented was effective in determining the daily parameters at 96% compliance with the actual measurements for the prediction of the minimum and maximum temperature for the next day and 83.27% for the prediction of atmospheric pressure.

Download Full-text

Understanding Spatial Variability of NO2 in Urban Areas Using Spatial Modelling and Data Fusion Approaches

Atmosphere ◽

10.3390/atmos12020179 ◽

2021 ◽

Vol 12 (2) ◽

pp. 179

Author(s):

Said Munir ◽

Martin Mayfield ◽

Daniel Coca

Keyword(s):

Data Fusion ◽

Spatial Variability ◽

Urban Areas ◽

Road Traffic ◽

Dispersion Model ◽

Low Cost ◽

Spatial Modelling ◽

City Centre ◽

Small Scale ◽

The City

Small-scale spatial variability in NO2 concentrations is analysed with the help of pollution maps. Maps of NO2 estimated by the Airviro dispersion model and land use regression (LUR) model are fused with measured NO2 concentrations from low-cost sensors (LCS), reference sensors and diffusion tubes. In this study, geostatistical universal kriging was employed for fusing (integrating) model estimations with measured NO2 concentrations. The results showed that the data fusion approach was capable of estimating realistic NO2 concentration maps that inherited spatial patterns of the pollutant from the model estimations and adjusted the modelled values using the measured concentrations. Maps produced by the fusion of NO2-LCS with NO2-LUR produced better results, with r-value 0.96 and RMSE 9.09. Data fusion adds value to both measured and estimated concentrations: the measured data are improved by predicting spatiotemporal gaps, whereas the modelled data are improved by constraining them with observed data. Hotspots of NO2 were shown in the city centre, eastern parts of the city towards the motorway (M1) and on some major roads. Air quality standards were exceeded at several locations in Sheffield, where annual mean NO2 levels were higher than 40 µg/m3. Road traffic was considered to be the dominant emission source of NO2 in Sheffield.

Download Full-text