scholarly journals Quantification of atmospheric nucleation and growth process as a single source of aerosol particles in a city

2017 ◽  
Author(s):  
Imre Salma ◽  
Veronika Varga ◽  
Zoltán Németh
Keyword(s):  
Growth Process ◽  
Particle Number ◽  
Particle Diameter ◽  
City Centre ◽  
Background Concentration ◽  
Time Interval ◽  
Single Source ◽  
Mean Values ◽  
Early Afternoon ◽  
The City

Abstract. Effects of new aerosol particle formation (NPF) and particle diameter growth process as a single source on atmospheric particle number concentrations were evaluated and quantified on the basis of experimental data sets obtained from particle number size distribution measurements in the city centre and near-city background of Budapest for 5 years. Nucleation strength factors separately for nucleation days (NSFnucl days) and for all days (NSFall days) were derived for seasons and full years. The former characteristics represents the concentration increment of ultrafine (UF) particle numbers with respect to background concentration due solely to nucleation specifically on nucleation days. The latter factor expresses the contribution of nucleation process to the background particle number concentrations in general, thus on a longer time interval such as season or year. The nucleation source had the largest effect on particle concentrations around noon and early afternoon as expected. During this time interval, it became the major source of particles in the near-city background. Nucleation increased the daily mean particle number concentrations on nucleation days by mean factors of 2.3 and 1.58 in the near-city background and city centre, respectively. Its effect was the largest in winter, which was explained with the substantially lower background concentration levels on nucleation days than that on non-nucleation days. On an annual time scale, 37 % of the UF particles were generated by nucleation in the near-city background, while NPF produced 13 % of UF particles in the city centre. The differences among the annual mean values, and among the corresponding seasonal mean values were likely caused by the variability in controlling factors from year to year. The values obtained represent lower limits of contributions. The shares determined imply that NPF is a non-negligible or substantial source of particles in near-city background environments and even in city centres, where the vehicular road emissions usually prevail. Atmospheric residence time of nucleation-mode particles was assessed by decay curve analysis of N6–25 concentrations in time, and a mean of 2:30 was obtained. The present study suggests that the health-related consequences of atmospheric NPF and growth process in cities should also be considered in addition to its urban climate implications.

scholarly journals Quantification of an atmospheric nucleation and growth process as a single source of aerosol particles in a city

2017 ◽  
Vol 17 (24) ◽  
pp. 15007-15017 ◽  
Author(s):  
Imre Salma ◽  
Veronika Varga ◽  
Zoltán Németh
Keyword(s):  
Growth Process ◽  
Particle Number ◽  
Urban Climate ◽  
Particle Diameter ◽  
City Centre ◽  
Time Interval ◽  
Single Source ◽  
Mean Values ◽  
Early Afternoon ◽  
The City

Abstract. Effects of a new aerosol particle formation (NPF) and particle diameter growth process as a single source of atmospheric particle number concentrations were evaluated and quantified on the basis of experimental data sets obtained from particle number size distribution measurements in the city centre and near-city background of Budapest for 5 years. Nucleation strength factors for a nucleation day (NSFNUC) and for a general day (NSFGEN) were derived separately for seasons and full years. The former characteristic represents the concentration increment of ultrafine (UF) particles specifically on nucleation days with respect to accumulation-mode (regional background) concentrations (particles with equivalent diameters of 100–1000 nm; N100−1000) due solely to the nucleation process. The latter factor expresses the contribution of nucleation to particle numbers on general days; thus, it represents a longer time interval such as season or year. The nucleation source had the largest effect on the concentrations around noon and early afternoon, as expected. During this time interval, it became the major source of particles in the near-city background. Nucleation increased the daily mean concentrations on nucleation days by mean factors of 2.3 and 1.58 in the near-city background and city centre, respectively. Its effect was largest in winter, which was explained by the substantially lower N100−1000 levels on nucleation days than those on non-nucleation days. On an annual timescale, 37 % of the UF particles were generated by nucleation in the near-city background, while NPF produced 13 % of UF particles in the city centre. The differences among the annual mean values, and among the corresponding seasonal mean values, were likely caused by the variability in controlling factors from year to year. The values obtained represent the lower limits of the contributions. The shares determined imply that NPF is a non-negligible or substantial source of particles in near-city background environments and even in city centres, where the vehicular road emissions usually prevail. Atmospheric residence time of nucleation-mode particles was assessed by a decay curve analysis, and a mean of 02:30 was obtained. The present study suggests that the health-related consequences of the atmospheric NPF and growth process in cities should also be considered in addition to its urban climate implications.

scholarly journals On the spatial distribution and evolution of ultrafine aerosols in urban air

2012 ◽  
Vol 12 (7) ◽  
pp. 16603-16646 ◽  
Author(s):  
M. Dall'Osto ◽  
X. Querol ◽  
A. Alastuey ◽  
C. O'Dowd ◽  
R. M. Harrison ◽  
...  
Keyword(s):  
Ultrafine Particles ◽  
Particle Number ◽  
Ground Level ◽  
City Centre ◽  
Atmospheric Conditions ◽  
Urban Background ◽  
Study Region ◽  
Urban City ◽  
Regional Background ◽  
The City

Abstract. Sources and evolution of ultrafine particles (<0.1 μ m diameter) were investigated both horizontally and vertically in the large urban agglomerate of Barcelona, Spain. Within the SAPUSS project (Solving Aerosol Problems by Using Synergistic Strategies), a large number of instruments was deployed simultaneously at different monitoring sites (road, two urban background, regional background, urban tower 150 μa.s.l., urban background tower site 80 m a.s.l.) during a 4 week period in September-October 2010. Particle number concentrations (N>5nm) are highly correlated with black carbon (BC) at all sites only under strong vehicular traffic influences. By contrast, under clean atmospheric conditions (low condensation sinks, CS) such correlation diverges towards much higher N/BC ratios at all sites, indicating additional sources of particles including secondary production of freshly nucleated particles. This is also evident in the urban background annual mean diurnal trend of N/BC, showing a midday peak in all seasons. Size-resolved aerosol distributions (N10-500) as well as particle number concentrations (N>5nm) allow us to identify two types of nucleation and growth events: a regional type event originating in the whole study region and impacting almost simultaneously the urban city of Barcelona and the surrounding background area; and an urban type which originates only within the city centre but whose growth continues while transported away from the city to the regional background. Furthermore, during these clean air days, higher N are found at tower level than at ground level only in the city centre whereas such a difference is not so pronounced at the remote urban background tower. In other words, this study suggests that the column of air above the city ground level possesses the best compromise between low CS and high vapour source, hence enhancing the concentrations of freshly nucleated particles. By contrast, within stagnant polluted atmospheric conditions, higher N and BC concentrations are always measured at ground level relative to tower level at all sites. Our study suggests that the city centre is a source of both non-volatile traffic primary (29–39%) and secondary freshly nucleated particles (up to 61–71%) at all sites. We suggest that organic compounds evaporating from freshly emitted traffic particles are a possible candidate for new particle formation within the city and urban plume.

scholarly journals High-resolution measurements from the airborne Atmospheric Nitrogen Dioxide Imager (ANDI)

2015 ◽  
Vol 8 (11) ◽  
pp. 4735-4754 ◽  
Author(s):  
J. P. Lawrence ◽  
J. S. Anand ◽  
J. D. Vande Hey ◽  
J. White ◽  
R. R. Leigh ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Column Density ◽  
Road Traffic ◽  
City Centre ◽  
Background Concentration ◽  
Atmospheric Nitrogen ◽  
Vertical Column ◽  
East Midlands ◽  
Test Flight ◽  
The City

Abstract. Nitrogen dioxide is both a primary pollutant with direct health effects and a key precursor of the secondary pollutant ozone. This paper reports on the development, characterisation and test flight of the Atmospheric Nitrogen Dioxide Imager (ANDI) remote sensing system. The ANDI system includes an imaging UV/Vis grating spectrometer able to capture scattered sunlight spectra for the determination of tropospheric nitrogen dioxide (NO2) concentrations by way of DOAS slant column density and vertical column density measurements. Results are shown for an ANDI test flight over Leicester City in the UK on a cloud-free winter day in February 2013. Retrieved NO2 columns gridded to a surface resolution of 80 m × 20 m revealed hotspots in a series of locations around Leicester City, including road junctions, the train station, major car parks, areas of heavy industry, a nearby airport (East Midlands) and a power station (Ratcliffe-on-Soar). In the city centre the dominant source of NO2 emissions was identified as road traffic, contributing to a background concentration as well as producing localised hotspots. Quantitative analysis revealed a significant urban increment over the city centre which increased throughout the flight.

scholarly journals Mobile measurements of ship emissions in two harbour areas in Finland

2014 ◽  
Vol 7 (1) ◽  
pp. 149-161 ◽  
Author(s):  
L. Pirjola ◽  
A. Pajunoja ◽  
J. Walden ◽  
J.-P. Jalkanen ◽  
T. Rönkkö ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Particle Number ◽  
City Centre ◽  
Particulate Emissions ◽  
Size Distributions ◽  
So2 Emissions ◽  
The Baltic Sea ◽  
Eu Directive ◽  
The Baltic ◽  
The City

Abstract. Four measurement campaigns were performed in two different environments – inside the harbour areas in the city centre of Helsinki, and along the narrow shipping channel near the city of Turku, Finland – using a mobile laboratory van during winter and summer conditions in 2010–2011. The characteristics of gaseous (CO, CO2, SO2, NO, NO2, NOx) and particulate (number and volume size distributions as well as PM2.5) emissions for 11 ships regularly operating on the Baltic Sea were studied to determine the emission parameters. The highest particle concentrations were 1.5 × 106 and 1.6 × 105 cm−3 in Helsinki and Turku, respectively, and the particle number size distributions had two modes. The dominating mode peaked at 20–30 nm, and the accumulation mode at 80–100 nm. The majority of the particle mass was volatile, since after heating the sample to 265 °C, the particle volume of the studied ship decreased by around 70%. The emission factors for NOx varied in the range of 25–100 g (kg fuel)−1, for SO2 in the range of 2.5–17.0 g (kg fuel)−1, for particle number in the range of (0.32–2.26) × 1016 # (kg fuel)−1, and for PM2.5 between 1.0–4.9 g (kg fuel)−1. The ships equipped with SCR (selective catalytic reduction) had the lowest NOx emissions, whereas the ships with DWI (direct water injection) and HAMs (humid air motors) had the lowest SO2 emissions but the highest particulate emissions. For all ships, the averaged fuel sulphur contents (FSCs) were less than 1% (by mass) but none of them was below 0.1% which will be the new EU directive starting 1 January 2015 in the SOx emission control areas; this indicates that ships operating on the Baltic Sea will face large challenges.

scholarly journals Multi-Temporal Change Detection Analysis of Vertical Sprawl over Limassol City Centre and Amathus Archaeological Site in Cyprus during 2015–2020 Using the Sentinel-1 Sensor and the Google Earth Engine Platform

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1884
Author(s):  
Athos Agapiou
Keyword(s):  
Change Detection ◽  
Satellite Images ◽  
Archaeological Site ◽  
Google Earth ◽  
City Centre ◽  
Time Interval ◽  
High Resolution Satellite Images ◽  
Multi Temporal ◽  
Google Earth Engine ◽  
The City

Urban sprawl can negatively impact the archaeological record of an area. In order to study the urbanisation process and its patterns, satellite images were used in the past to identify land-use changes and detect individual buildings and constructions. However, this approach involves the acquisition of high-resolution satellite images, the cost of which is increases according to the size of the area under study, as well as the time interval of the analysis. In this paper, we implemented a quick, automatic and low-cost exploration of large areas, for addressing this purpose, aiming to provide at a medium resolution of an overview of the landscape changes. This study focuses on using radar Sentinel-1 images to monitor and detect multi-temporal changes during the period 2015–2020 in Limassol, Cyprus. In addition, the big data cloud platform, Google Earth Engine, was used to process the data. Three different change detection methods were implemented in this platform as follow: (a) vertical transmit, vertical receive (VV) and vertical transmit, horizontal receive (VH) polarisations pseudo-colour composites; (b) the Rapid and Easy Change Detection in Radar Time-Series by Variation Coefficient (REACTIV) Google Earth Engine algorithm; and (c) a multi-temporal Wishart-based change detection algorithm. The overall findings are presented for the wider area of the Limassol city, with special focus on the archaeological site of “Amathus” and the city centre of Limassol. For validation purposes, satellite images from the multi-temporal archive from the Google Earth platform were used. The methods mentioned above were able to capture the urbanization process of the city that has been initiated during this period due to recent large construction projects.

scholarly journals Functional Dimensions at 'Kuala Lumpur Waterfront'

2016 ◽  
Vol 1 (1) ◽  
pp. 7-17
Author(s):  
Nurul Syala Abdul Latip ◽  
Shuhana Shamsudin ◽  
Mohd Shahir Liew
Keyword(s):  
Publishing House ◽  
Urban River ◽  
City Centre ◽  
Time Interval ◽  
Kuala Lumpur ◽  
Main Mode ◽  
Contextual Integration ◽  
Medium Level ◽  
Mode Of Transportation ◽  
The City

The 'Kuala Lumpur Waterfront' may be unfamiliar to many. Kuala Lumpur is a city that originates at the confluence of two rivers, the Klang and Gombak Rivers. The waterfront used to be very busy with activities when it was once a trading post for the export of tin. This was once the lifeline of the city - its main mode of transportation. The activity at the waterfront has changed over the years along with the social, economic and physical development of the city. Many waterfront cities throughout the world have gone through similar changes when the mode of transportation changed from water to the motor system. A number of cities have made efforts to integrate the cities' activities with their water body. This research attempts to investigate the functional aspects at the Kuala Lumpur waterfront within the city centre in terms of its level of contextual integration with the urban rivers in the current context. The technique adopted for this research is field observations which include building use survey and time interval observation to investigate the Junctional aspects in ten demarcated zones along the Kuala Lumpur waterfront within the city centre. The research concluded with the finding that all the zones have medium level of contextual integration between the waterfront and the urban river in terms of its building use, which depends much on the continuity of activities, their positioning location, accessibility and the provision of space and facilities. © 2016 The Authors. Published for AMER ABRA by e-International Publishing House, Ltd., UK.. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, UniversitiTeknologi MARA, Malaysia. DOI: http://dx.doi.org/10.21834/aje-bs.v1i1.164 Keywords: Contextual integration, waterfront, urban river, activity

scholarly journals On the spatial distribution and evolution of ultrafine particles in Barcelona

2013 ◽  
Vol 13 (2) ◽  
pp. 741-759 ◽  
Author(s):  
M. Dall'Osto ◽  
X. Querol ◽  
A. Alastuey ◽  
C. O'Dowd ◽  
R. M. Harrison ◽  
...  
Keyword(s):  
Ultrafine Particles ◽  
Particle Number ◽  
Ground Level ◽  
City Centre ◽  
Atmospheric Conditions ◽  
Urban Background ◽  
Urban City ◽  
Regional Background ◽  
The City ◽  
Background Area

Abstract. Sources and evolution of ultrafine particles were investigated both horizontally and vertically in the large urban agglomerate of Barcelona, Spain. Within the SAPUSS project (Solving Aerosol Problems by Using Synergistic Strategies), a large number of instruments was deployed simultaneously at different monitoring sites (road, two urban background, regional background, urban tower 150 m a.s.l., urban background tower site 80 m a.s.l.) during a 4 week period in September–October 2010. Particle number concentrations (N>5 nm) are highly correlated with black carbon (BC) at all sites only under strong vehicular traffic influences. By contrast, under cleaner atmospheric conditions (low condensation sink, CS) such correlation diverges towards much higher N/BC ratios at all sites, indicating additional sources of particles including secondary production of freshly nucleated particles. Size-resolved aerosol distributions (N10–500) as well as particle number concentrations (N>5 nm) allow us to identify three types of nucleation and growth events: (1) a regional type event originating in the whole study region and impacting almost simultaneously the urban city of Barcelona and the surrounding urban background area; (2) a regional type event impacting only the regional background area but not the urban agglomerate; (3) an urban type event which originates only within the city centre but whose growth continues while transported away from the city to the regional background. Furthermore, during these clean air days, higher N are found at tower level than at ground level only in the city centre whereas such a difference is not so pronounced at the remote urban background tower. In other words, this study suggests that the column of air above the city ground level possesses the optimal combination between low CS and high vapour source, hence enhancing the concentrations of freshly nucleated particles. By contrast, within stagnant polluted atmospheric conditions, higher N and BC concentrations are always measured at ground level relative to tower level at all sites. Our study suggests that the city centre of Barcelona is a source of non-volatile traffic primary particles (29–39% of N>5 nm), but other sources, including secondary freshly nucleated particles contribute up to 61–71% of particle number (N>5 nm) at all sites. We suggest that organic compounds evaporating from freshly emitted traffic particles are a possible candidate for new particle formation within the city and urban plume.

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

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.

scholarly journals High-resolution measurements from the airborne Atmospheric Nitrogen Dioxide Imager (ANDI)

2015 ◽  
Vol 8 (6) ◽  
pp. 5677-5734
Author(s):  
J. P. Lawrence ◽  
J. S. Anand ◽  
J. D. Vande Hey ◽  
R. R. Leigh ◽  
P. S. Monks ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Hot Spots ◽  
Column Density ◽  
Road Traffic ◽  
City Centre ◽  
Background Concentration ◽  
Atmospheric Nitrogen ◽  
Vertical Column ◽  
Test Flight ◽  
The City

Abstract. Nitrogen Dioxide is both a primary pollutant with direct health effects and a key precursor of the secondary pollutant ozone. This paper reports on the development, characterisation and test flight of the Atmospheric Nitrogen Dioxide Imager (ANDI) remote sensing system. The ANDI system includes an imaging (UV)-vis grating spectrometer able to capture scattered sunlight spectra for the determination of tropospheric nitrogen dioxide (NO2) concentrations by way of DOAS slant column density and vertical column density measurements. Results are shown for an ANDI test flight over Leicester City in the UK. Retrieved NO2 columns at a surface resolution of 80 m x 20 m revealed hot spots in a series of locations around Leicester City, including road junctions, the train station, major car parks, areas of heavy industry, a nearby airport (East Midlands) and a power station (Ratcliffe-on-Soar). In the city centre the dominant source of NO2 emissions was identified as road traffic, contributing to a background concentration as well as producing localised hot spots. Quantitative analysis revealed a significant urban increment over the city centre which increased throughout the flight.

scholarly journals Dynamic and timing properties of new aerosol particle formation and consecutive growth events

2019 ◽  
Vol 19 (9) ◽  
pp. 5835-5852 ◽  
Author(s):  
Imre Salma ◽  
Zoltán Németh
Keyword(s):  
Aerosol Particle ◽  
Dynamic Properties ◽  
Particle Formation ◽  
City Centre ◽  
Time Interval ◽  
Growth Processes ◽  
Timing Properties ◽  
The City ◽  
Particle Formation And Growth ◽  
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 atmospheric new aerosol particle formation (NPF) and 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 at a typical rate of 7.3 nm h−1. Nucleation starts approximately 1 h earlier in the near-city background, and 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. New particle formation and growth processes advance in a different manner in the city and its close environment. This could likely be related to diversities in atmospheric composition, chemistry and physics. Monthly distributions and relationships among the properties mentioned provided 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 a log-normal distribution function. Most extreme dynamic properties could not be explained by available single or compound variables. Approximately 40 % of the NPF and growth events exhibited broad beginning, which can be an urban feature. For doublets, the later onset frequently shows more intensive particle formation and growth than the first onset by a typical factor of approximately 1.5. The first event is attributed to a regional type, while the second event, superimposed on the first, is often associated with subregional, thus urban NPF and growth processes.

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