scholarly journals Simplifying aerosol size distributions modes simultaneously detected at four monitoring sites during SAPUSS

2013 ◽  
Vol 13 (10) ◽  
pp. 27387-27422
Author(s):  
M. Brines ◽  
M. Dall'Osto ◽  
D. C. S. Beddows ◽  
R. M. Harrison ◽  
X. Querol
Keyword(s):  
Spatial Distribution ◽  
Urban Areas ◽  
Aerosol Size Distribution ◽  
Size Distributions ◽  
Urban Background ◽  
Background Site ◽  
Regional Background ◽  
Background Pollution ◽  
Aerosol Sources ◽  
The City

Abstract. The analysis of aerosol size distributions is a useful tool for understanding the sources and the processes influencing particle number concentrations (N) in urban areas. Hence, during the one month SAPUSS campaign (Solving Aerosol Problems by Using Synergistic Strategies, EU Marie Curie Action) in autumn 2010 in Barcelona (Spain), four SMPS (Scanning Mobility Particle Sizers) were simultaneously deployed at four monitoring sites: a road side (RSsite), an urban background site located in the city (UBsite), an urban background located in the nearby hills of the city (Torre Collserola, TCsite) and a regional background site located about fifty km from the Barcelona urban areas (RBsite). The spatial distribution of sites allows study of the aerosol temporal variability as well as the spatial distribution, progressively moving away from urban aerosol sources. In order to interpret the datasets collected, a k-means cluster analysis was performed on the combined SMPS datasets. This resulted in nine clusters describing all aerosol size distributions from the four sites. In summary there were three main categories (with three clusters in each category): "Traffic" (Traffic 1 "Tclus1" – 8%, Traffic 2 "Tclus2" – 13%, Traffic 3, "Tclus3" – 9%), "Background Pollution" (Urban Background 1 "UBclus1" – 21%, Regional Background 1, "RBclus1" – 15%, Regional Background 2, "RBclus2" – 18%) and "Special cases" (Nucleation "NUclus" – 5%, Regional Nitrate, "NITclus" – 6%, and Mix "MIXclus" – 5%). As expected, the frequency of traffic clusters (Tclus1–3) followed the order RSsite, UBsite, TCsite, and RBsite. These showed typical traffic modes mainly distributed at 20–40 nm. The urban background sites (UBsite and TCsite) reflected also as expected urban background number concentrations (average values, N = 2.4×104 cm−3 relative to 1.2×105 cm−3 seen at RSsite). The cluster describing the urban background pollution (UBclus1) could be used to monitor the sea breeze circulation towards the regional background study area. Overall, the RBsite was mainly characterised by two different regional background aerosol size distributions: whilst both exhibited low N (2.6×103 for RBclus1 and 2.3×103 cm−3 for RBclus2), RBclus1 had average PM10 concentrations higher than RBclus1 (30 vs. 23 μg m−3). As regards the minor aerosol size distribution clusters, the "Nucleation" cluster was observed during daytime whilst the "Regional Nitrate" was mainly seen at night. The ninth cluster ("Mix") was the least well defined and likely composed of a number of aerosol sources. When correlating averaged values of N, NO2 and PM (particulate mass) for each k-means cluster, a linear correlation between N and NO2 with values progressively increasing from the regional site RBsite to the road site RSsite was found. This points to vehicular traffic as the main source of both N and NO2. By contrast, such an association does not exist for the case of the nucleation cluster, where the highest N is found with low NO2 and PM. Finally, the clustering technique allowed study of the impact of meteorological parameters on the traffic N emissions. This study confirms the shrinking of freshly emitted particles (by about 20% within 1 km in less than 10 min; Dall'Osto et al., 2011a) as particles are transported from the traffic hot spots towards urban background environments. Additionally, for a given well defined aerosol size distribution (Tclus2) associated to primary aerosol emissions from road traffic we found that N5–15 nm concentrations can vary up to a factor of eight. Within our measurement range (5–228 nm), we found that ultrafine particles within the range 5–15 nm are the most dynamic, being a complex ensemble of primary evaporating traffic particles, traffic tailpipe new particle formation and non-traffic new particle formation.

scholarly journals Simplifying aerosol size distributions modes simultaneously detected at four monitoring sites during SAPUSS

2014 ◽  
Vol 14 (6) ◽  
pp. 2973-2986 ◽  
Author(s):  
M. Brines ◽  
M. Dall'Osto ◽  
D.C.S. Beddows ◽  
R. M. Harrison ◽  
X. Querol
Keyword(s):  
Urban Areas ◽  
Aerosol Size Distribution ◽  
Data Sets ◽  
Size Distributions ◽  
Urban Background ◽  
Background Site ◽  
Regional Background ◽  
Background Pollution ◽  
Aerosol Sources ◽  
The City

Abstract. The analysis of aerosol size distributions is a useful tool for understanding the sources and the processes influencing particle number concentrations (N) in urban areas. Hence, during the one-month SAPUSS campaign (Solving Aerosol Problems by Using Synergistic Strategies, EU Marie Curie Action) in autumn 2010 in Barcelona (Spain), four SMPSs (Scanning Mobility Particle Sizer) were simultaneously deployed at four monitoring sites: a road side (RSsite), an urban background site located in the city (UBsite), an urban background site located in the nearby hills of the city (Torre Collserola, TCsite) and a regional background site located about 50 km from the Barcelona urban areas (RBsite). The spatial distribution of sites allows study of the aerosol temporal variability as well as the spatial distribution, progressively moving away from urban aerosol sources. In order to interpret the data sets collected, a k-means cluster analysis was performed on the combined SMPS data sets. This resulted in nine clusters describing all aerosol size distributions from the four sites. In summary there were three main categories (with three clusters in each category): "Traffic" (Traffic 1, "Tclus_1" – 8%; Traffic 2, "Tclus_2" – 13%; and Traffic 3, "Tclus_3" – 9%) "Background Pollution" (Urban Background 1, "UBclus_1" – 21%; Regional Background 1, "RBclus_1" – 15%; and Regional Background 2, "RBclus_2" – 18%) and "Special Cases" (Nucleation, "NUclus" – 5%; Regional Nitrate, "NITclus" – 6%; and Mix, "MIXclus" – 5%). As expected, the frequency of traffic clusters (Tclus_1–3) followed the order RSsite, UBsite, TCsite, and RBsite. These showed typical traffic modes mainly distributed at 20–40 nm. The urban background sites (UBsite and TCsite) reflected also as expected urban background number concentrations (average values, N = 1.0 × 104 cm−3 and N = 5.5 × 103 cm−3, respectively, relative to 1.3 × 104 cm−3 seen at RSsite). The cluster describing the urban background pollution (UBclus_1) could be used to monitor the sea breeze circulation towards the regional background study area. Overall, the RBsite was mainly characterised by two different regional background aerosol size distributions: whilst both exhibited low N (2.7 × 103 for RBclus_1 and 2.2 × 103 cm−3 for RBclus_2), RBclus_1 had average PM10 concentrations higher than RBclus_2 (27 vs. 23 μg m−3). As regards the minor aerosol size distribution clusters, the "Nucleation" cluster was observed during daytime, whilst the "Regional Nitrate" was mainly seen at night. The ninth cluster ("Mix") was the least well defined and likely composed of a number of aerosol sources. When correlating averaged values of N, NO2 and PM (particulate mass) for each k-means cluster, a linear correlation between N and NO2 with values progressively increasing from the regional site RBsite to the road site RSsite was found. This points to vehicular traffic as the main source of both N and NO2. By contrast, such an association does not exist for the case of the nucleation cluster, where the highest N is found with low NO2 and PM. Finally, the clustering technique allowed study of the impact of meteorological parameters on the traffic N emissions. This study confirms the shrinking of freshly emitted particles (by about 20% within 1 km in less than 10 min; Dall'Osto et al., 2011a) as particles are transported from the traffic hot spots towards urban background environments. Additionally, for a given well-defined aerosol size distribution (Tclus_2) associated with primary aerosol emissions from road traffic we found that N5–15 nm concentrations can vary up to a factor of eight. Within our measurement range of SMPSs (N15–228 nm) and Condensation Particle Counters (CPCs, N>5 nm), we found that ultrafine particles within the range 5–15 nm in urban areas are the most dynamic, being a complex ensemble of primary evaporating traffic particles, traffic tailpipe new particle formation and non-traffic new particle formation.

Determination of atmospheric aerosol particle size distribution and visibility using a mobile laboratory

1982 ◽  
Vol 60 (8) ◽  
pp. 1101-1107
Author(s):  
C. V. Mathai ◽  
A. W. Harrison
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Atmospheric Aerosols ◽  
Suspended Particle ◽  
Aerosol Size Distribution ◽  
Size Distributions ◽  
Mobile Laboratory ◽  
Mean Values ◽  
The City

As part of an ongoing general research program on the effects of atmospheric aerosols on visibility and its dependence on aerosol size distributions in Calgary, this paper presents the results of a comparative study of particle size distribution and visibility in residential (NW) and industrial (SE) sections of the city using a mobile laboratory. The study was conducted in the period October–December, 1979. An active scattering aerosol spectrometer measured the size distributions and the corresponding visibilities were deduced from scattering coefficients measured with an integrating nephelometer.The results of this transit study show significantly higher suspended particle concentrations and reduced visibilities in the SE than in the NW. The mean values of the visibilities are 44 and 97 km for the SE and the NW respectively. The exponent of R (particle radius) in the power law aerosol size distribution has a mean value of −3.36 ± 0.24 in the SE compared with the corresponding value of −3.89 ± 0.39 for the NW. These results arc in good agreement with the observations of Alberta Environment; however, they are in contradiction with a recent report published by the City of Calgary.

scholarly journals Spatial distribution of triatomines (Reduviidae: Triatominae) in urban areas of the city of Salvador, Bahia, Brazil

2011 ◽  
Vol 5 (2) ◽  
pp. 199 ◽  
Author(s):  
Karine De Souza O. Santana ◽  
Maria Emília Bavia ◽  
Artur Dias Lima ◽  
Isabel Cristina S. Guimarães ◽  
Ênio Silva Soares ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Urban Areas ◽  
The City

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.

La cittŕ in-visibile. Analisi statistica spaziale degli stranieri nel comune di Roma

2009 ◽  
pp. 59-78
Author(s):  
Francesco Giovanni Truglia
Keyword(s):  
Spatial Distribution ◽  
Statistical Analysis ◽  
Urban Area ◽  
Urban Areas ◽  
Social Geography ◽  
Spatial Statistical Analysis ◽  
Units Of Analysis ◽  
The City ◽  
Statistical Indicators

- This contribution is aimed at builgin a sort of social geography of multicultural cohabitation in the municipality of Rome and identifying ethnic locations based a series of statistical indicators - some of which unpublished - with the use of certain instruments of spatial statistical analysis. The study is articulated on two levels. The first examines the urban areas and offers a horizontal overview of foreigners' spatial distribution. The second takes into consideration units of analysis referred to different administrative divisions (City, Municipality, urban area). This is a vertical analysis that takes into account the specific aspects of a certain urban area compared to the city and municipality of reference.

Representativeness and variability of PM2.5 mass concentrations and black carbon near traffic and urban background monitoring stations/Repräsentativität und Variabilität von PM2.5-Massenkonzentrationen und schwarzem Kohlenstoff in der Nähe von Verkehrs- und städtischen Luftgütemessstationen.

Gefahrstoffe ◽  
2019 ◽  
Vol 79 (06) ◽  
pp. 217-226
Author(s):  
H. D. Alas ◽  
S. Pfeifer ◽  
A. Wiesner ◽  
B. Wehner ◽  
K. Weinhold ◽  
...  
Keyword(s):  
Air Pollution ◽  
Black Carbon ◽  
Urban Areas ◽  
Mass Concentration ◽  
Spatial Distributions ◽  
Urban Background ◽  
Regular Monitoring ◽  
The City ◽  
Mass Concentrations ◽  
Monitoring Stations

Mobile measurements of PM2.5 and black carbon (BC) mass concentrations were performed near regular monitoring stations in order to gain deeper understanding of the drivers of pedestrian exposure to traffic-related air pollution. The following investigations have been done: A) Yearlong measurements in an area around a street canyon approximately 3 km airline distance from the city center of Leipzig showed that the spatial distributions of both pollutants are elevated during wintertime. The patterns of the BC mass concentration, however, consistently showed a strong influence from traffic emissions in the street, while the PM2.5 mass concentration was more dependent on the regional background and less on urban sources. B) Measurements in the city of Dresden near two regular monitoring stations, one at a roadside and one in urban background areas revealed differences between the two in terms of the BC mass concentrations, with slightly higher concentrations at the traffic area. However, no significant differences between the spatial distributions of PM2.5 mass concentrations were observed. The background measurements of the PM2.5 mass concentrations seem to be generally representative for the residential area. C) Measurements near a regular monitoring station located at a junction of the inner-city ring road of Leipzig showed that it is representative of its immediate vicinity in terms of BC mass concentrations. However, the PM2.5 mass concentration varied by a factor 2, reaching the highest levels near in the central tram station about 200 m away. The central tram station seems to significantly influence the PM2.5 mass concentration. These results of the three studies provide a better understanding of the variability of these two parameters in urban areas in Leipzig and Dresden, helping local policy makers to interpret better the measured air pollution.

scholarly journals Epidemiological aspects and spatial distribution of human and canine visceral leishmaniasis in an endemic area in northeastern Brazil

2017 ◽  
Vol 12 (1) ◽  
Author(s):  
Roseane Campos ◽  
Márcio Santos ◽  
Gabriel Tunon ◽  
Luana Cunha ◽  
Lucas Magalhães ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Visceral Leishmaniasis ◽  
Urban Areas ◽  
Systemic Disease ◽  
Northeastern Brazil ◽  
Sand Fly ◽  
Canine Visceral Leishmaniasis ◽  
Positive Serology ◽  
Exponential Increase ◽  
The City

Visceral leishmaniasis (VL) is a systemic disease endemic in tropical countries and transmitted through sand flies. In particular, <em>Canis familiaris</em> (or domesticated dogs) are believed to be a major urban reservoir for the parasite causing the disease Leishmania. The average number of human VL cases was 58 per year in the state of Sergipe. The city of Aracaju, capital of Sergipe in Northeastern Brazil, had 159 cases of VL in humans. Correlatively, the percentage of serologically positive dogs for leishmaniasis increased from 4.73% in 2008 to 12.69% in 2014. Thus, these studies aimed to delineate the spatial distribution and epidemiological aspects of human and canine VL as mutually supportive for increased incidence. The number of human cases of VL and the frequency of canine positive serology for VL both increased between 2008 and 2014. Spatial distribution analyses mapped areas of the city with the highest concentration of human and canine VL cases. The neighbourhoods that showed the highest disease frequency were located on the outskirts of the city and in urbanised areas or subjected to development. Exponential increase in VL-positive dogs further suggests that the disease is expanding in urban areas, where it can serve as a reservoir for transmission of dogs to humans via the sand fly vector.

scholarly journals Anthropogenic and biogenic influence on VOC fluxes at an urban background site in Helsinki, Finland

2016 ◽  
Author(s):  
Pekka Rantala ◽  
Leena Järvi ◽  
Risto Taipale ◽  
Terhi K. Laurila ◽  
Johanna Patokoski ◽  
...  
Keyword(s):  
Anthropogenic Activities ◽  
Anthropogenic Sources ◽  
City Centre ◽  
Anthropogenic Source ◽  
Strong Correlations ◽  
Urban Background ◽  
Background Site ◽  
Carbon Dioxide Co2 ◽  
The City ◽  
Urban Background Site

Abstract. We measured volatile organic compounds (VOC), carbon dioxide (CO2) and carbon monoxide (CO) at an urban background site near the city centre of Helsinki, Finland, Northern Europe. The VOC and CO2 measurements were obtained between January 2013 and September 2014 whereas for CO a shorter measurement campaign in April–May 2014 was conducted. Both anthropogenic and biogenic sources were identified for VOCs in the study. Strong correlations between VOC fluxes and CO fluxes and traffic rates indicated anthropogenic source of many VOCs. The VOC with highest emission to the atmosphere was methanol which originated mostly from traffic and other anthropogenic sources. Traffic was also a major source for aromatic compounds in all seasons whereas isoprene was mostly emitted from biogenic sources during summer. Small traffic related isoprene emissions were detected during other seasons. Generally, the VOC fluxes were found to be small compared with previous urban VOC flux studies. However, the differences were probably caused by lower anthropogenic activities as the CO2 fluxes were also relatively small at the site.

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.

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