scholarly journals Traffic is a major source of atmospheric nanocluster aerosol

2017 ◽  
Vol 114 (29) ◽  
pp. 7549-7554 ◽  
Author(s):  
Topi Rönkkö ◽  
Heino Kuuluvainen ◽  
Panu Karjalainen ◽  
Jorma Keskinen ◽  
Risto Hillamo ◽  
...  
Keyword(s):  
Atmospheric Aerosol ◽  
Urban Areas ◽  
Aerosol Particles ◽  
Significant Risk ◽  
Ambient Air ◽  
Road Transportation ◽  
Total Particle ◽  
Traffic Rate ◽  
Road Study ◽  
Roadside Environment

In densely populated areas, traffic is a significant source of atmospheric aerosol particles. Owing to their small size and complicated chemical and physical characteristics, atmospheric particles resulting from traffic emissions pose a significant risk to human health and also contribute to anthropogenic forcing of climate. Previous research has established that vehicles directly emit primary aerosol particles and also contribute to secondary aerosol particle formation by emitting aerosol precursors. Here, we extend the urban atmospheric aerosol characterization to cover nanocluster aerosol (NCA) particles and show that a major fraction of particles emitted by road transportation are in a previously unmeasured size range of 1.3–3.0 nm. For instance, in a semiurban roadside environment, the NCA represented 20–54% of the total particle concentration in ambient air. The observed NCA concentrations varied significantly depending on the traffic rate and wind direction. The emission factors of NCA for traffic were 2.4·1015 (kgfuel)−1 in a roadside environment, 2.6·1015 (kgfuel)−1 in a street canyon, and 2.9·1015 (kgfuel)−1 in an on-road study throughout Europe. Interestingly, these emissions were not associated with all vehicles. In engine laboratory experiments, the emission factor of exhaust NCA varied from a relatively low value of 1.6·1012 (kgfuel)−1 to a high value of 4.3·1015 (kgfuel)−1. These NCA emissions directly affect particle concentrations and human exposure to nanosized aerosol in urban areas, and potentially may act as nanosized condensation nuclei for the condensation of atmospheric low-volatile organic compounds.

scholarly journals Production, growth and properties of ultrafine atmospheric aerosol particles in an urban environment

2010 ◽  
Vol 10 (6) ◽  
pp. 13689-13721
Author(s):  
I. Salma ◽  
T. Borsós ◽  
T. Weidinger ◽  
P. Aalto ◽  
T. Hussein ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Atmospheric Aerosol ◽  
Ultrafine Particles ◽  
Particle Number ◽  
Aerosol Particles ◽  
Formation Rate ◽  
Number Concentration ◽  
Nucleation Mode ◽  
Total Particle Number ◽  
Total Particle

Abstract. Number concentrations of atmospheric aerosol particles were measured by a flow-switching type differential mobility particle sizer in an electrical mobility diameter range of 6–1000 nm in 30 channels near central Budapest with a time resolution of 10 min continuously from 3 November 2008 to 2 November 2009. Daily median number concentrations of particles varied from 3.8×103 to 29×103 cm−3 with a yearly median of 11.8×103 cm−3. Contribution of ultrafine particles to the total particle number ranged from 58 to 92% with a mean ratio and standard deviation of (79±6)%. Daily average number concentrations in various size fractions and contribution of ultrafine particles to the total particle number showed no seasonal dependency. Monthly mean number size distributions were similar to each other. Overall mean for the number median mobility diameter of the Aitken and accumulation modes were 26 and 93 nm, respectively, which are substantially smaller than for rural or background environments. The Aitken and accumulation modes contributed similarly to the total particle number concentrations at the actual measurement location. Median diameters of the Aitken and accumulation modes were shifted to larger values before nucleation started and over the growth process, which can be related to the presence of aged aerosol under the conditions that favour nucleation and growth. Particle concentrations were usually increased substantially after nucleations. Overall mean and standard deviation of the nucleation mode number concentrations were (10.4±2.8)×103 cm−3. Mean ratio and standard deviation of the nucleation mode number concentration to the total particle number concentration that was averaged for two hours just before the formation was detected was 2.3±1.1. Nucleation unambiguously occurred on 83 days, which represent 27% of all relevant days. Its frequency showed a remarkable seasonal variation with a minimum of 7.3% in winter and a maximum of 44% in spring. Formation rate of particles with a diameter of 6 nm varied between 1.65 and 12.5 cm−3 s−1 with a mean and standard deviation of (4.2±2.5) cm−3 s−1. Seasonal dependency for the formation rate could not be identified. Growth curves of nucleated particles were usually superimposed on the characteristic diurnal pattern of road traffic direct emissions. The growth rate of the nucleation mode with a median diameter of 6 nm varied from 2.0 to 13.3 nm h−1 with a mean and standard deviation of (7.7±2.4) nm h−1. There was an indicative tendency for larger growth rates in summer and for smaller values in winter. Several indirect evidences suggest that the nucleation events occurred at least over the whole city, and were of regional type.

scholarly journals Towards a sustainable road transportation system in urban areas: A case study of Owerri, Nigeria

2021 ◽  
Vol 1 (1) ◽  
pp. 014-029
Author(s):  
Onyeka JO ◽  
Obi LE ◽  
Igiri VC
Keyword(s):  
Urban Areas ◽  
Air Pollutants ◽  
Ambient Air ◽  
Field Work ◽  
Road Transport ◽  
Road Transportation ◽  
Policy Measures ◽  
Almost All ◽  
Commuter Vehicles

Urban Areas in almost all cases develop outwards from the centre. Public facilities (schools, offices, markets) are usually located at about the centre while residential abodes radiate outwards. Such development pattern necessitates road transportation movement to the centre. This paper examines strategies that can be adopted to achieve the necessary movement in a sustainable manner for these urban areas, with Owerri Nigeria as a case study. A field study was conducted to ascertain the total passenger requirement, number and mix of passenger vehicles as well as measure three main road transport-induced air pollutants. The result of the field work showed existing commuter vehicles mix of 56.2:63.7: 19.6:1.6:1 for salons, wagons, mini-buses, coaster buses and big buses respectively, of a total of 85,950 vehicles. The survey also revealed ambient air pollutants level higher than the recommended standards. A new model was developed to achieve a vehicles remix of 10:33:53: 14:1 of same vehicle types and reduction in traffic volume and target air pollutants. The analyses showed that mini-buses and coaster buses have advantage over salon cars, wagon vehicles and big buses in terms of traffic congestions and pollutants release into the environment. The two bus types have least pollutants release per passenger carried. An optimal vehicle remix, which gives higher priority to these buses has been shown to reduce congestion by 40%, Carbon monoxide by 40%, Nitrogen Dioxide by 50% and Methane by 50%. Based on the findings, it is recommended that vehicular remix of 10:33:53:14:1, for salon: wagon: mini-buses: coaster buses: big buses be adopted for Owerri commuters’ transportation need. Some policy measures were put forward to help achieve this. The measures include an outright ban on use of low-passenger-carrying vehicles for commercial purposes.

scholarly journals Health benefits of on-road transportation pollution control programs in China

2020 ◽  
Vol 117 (41) ◽  
pp. 25370-25377
Author(s):  
Haikun Wang ◽  
Xiaojing He ◽  
Xinyu Liang ◽  
Ernani F. Choma ◽  
Yifan Liu ◽  
...  
Keyword(s):  
Public Health ◽  
Air Pollution ◽  
Air Quality ◽  
Urban Areas ◽  
Emission Control ◽  
Ambient Air ◽  
Control Measures ◽  
Ambient Air Pollution ◽  
Vehicle Emission ◽  
Road Transportation

China started to implement comprehensive measures to mitigate traffic pollution at the end of 1990s, but the comprehensive effects, especially on ambient air quality and public health, have not yet been systematically evaluated. In this study, we analyze the effects of vehicle emission control measures on ambient air pollution and associated deaths attributable to long-term exposures of fine particulate matter (PM2.5) and O3based on an integrated research framework that combines scenario analysis, air quality modeling, and population health risk assessment. We find that the total impact of these control measures was substantial. Vehicular emissions during 1998–2015 would have been 2–3 times as large as they actually were, had those measures not been implemented. The national population-weighted annual average concentrations of PM2.5and O3in 2015 would have been higher by 11.7 μg/m3and 8.3 parts per billion, respectively, and the number of deaths attributable to 2015 air pollution would have been higher by 510 thousand (95% confidence interval: 360 thousand to 730 thousand) without these controls. Our analysis shows a concentration of mortality impacts in densely populated urban areas, motivating local policymakers to design stringent vehicle emission control policies. The results imply that vehicle emission control will require policy designs that are more multifaceted than traditional controls, primarily represented by the strict emission standards, with careful consideration of the challenges in coordinated mitigation of both PM2.5and O3in different regions, to sustain improvement in air quality and public health given continuing swift growth in China’s vehicle population.

scholarly journals Production, growth and properties of ultrafine atmospheric aerosol particles in an urban environment

2011 ◽  
Vol 11 (3) ◽  
pp. 1339-1353 ◽  
Author(s):  
I. Salma ◽  
T. Borsós ◽  
T. Weidinger ◽  
P. Aalto ◽  
T. Hussein ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Atmospheric Aerosol ◽  
Particle Number ◽  
Aerosol Particles ◽  
Formation Rate ◽  
Particle Formation ◽  
Number Concentration ◽  
New Particle Formation ◽  
Total Particle Number ◽  
Total Particle

Abstract. Number concentrations of atmospheric aerosol particles were measured by a flow-switching type differential mobility particle sizer in an electrical mobility diameter range of 6–1000 nm in 30 channels near central Budapest with a time resolution of 10 min continuously from 3 November 2008 to 2 November 2009. Daily median number concentrations of particles varied from 3.8 × 103 to 29 ×103 cm−3 with a yearly median of 11.8 × 103 cm−3. Contribution of ultrafine particles to the total particle number ranged from 58 to 92% with a mean ratio and standard deviation of (79 ± 6)%. Typical diurnal variation of the particle number concentration was related to the major emission patterns in cities, new particle formation, sinks of particles and meteorology. Shapes of the monthly mean number size distributions were similar to each other. Overall mean for the number median mobility diameter of the Aitken and accumulation modes were 26 and 93 nm, respectively, which are substantially smaller than for rural or background environments. The Aitken and accumulation modes contributed similarly to the total particle number concentrations at the actual measurement location. New particle formation and growth unambiguously occurred on 83 days, which represent 27% of all relevant days. Hence, new particle formation and growth are not rare phenomena in Budapest. Their frequency showed an apparent seasonal variation with a minimum of 7.3% in winter and a maximum of 44% in spring. New particle formation events were linked to increased gas-phase H2SO4 concentrations. In the studied area, new particle formation is mainly affected by condensation sink and solar radiation. The formation process seems to be not sensitive to SO2, which was present in a yearly median concentration of 6.7 μg m−3. This suggests that the precursor gas was always available in excess. Formation rate of particles with a diameter of 6 nm varied between 1.65 and 12.5 cm−3 s−1 with a mean and standard deviation of (4.2 ± 2.5) cm−3 s−1. Seasonal dependency for the formation rate could not be identified. Growth curves of nucleated particles were usually superimposed on the characteristic diurnal pattern of road traffic direct emissions. The growth rate of the nucleation mode with a median diameter of 6 nm varied from 2.0 to 13.3 nm h−1 with a mean and standard deviation of (7.7 ± 2.4) nm h−1. There was an indicative tendency for larger growth rates in summer and for smaller values in winter. New particle formation events increased the total number concentration by a mean factor and standard deviation of 2.3 ± 1.1 relative to the concentration that occurred immediately before the event. Several indirect evidences suggest that the new particle formation events occurred at least over the whole city, and were of regional type. The results and conclusions presented are the first information of this kind for the region over one-year long time period.

scholarly journals Development of Land Use Regression Model for Seasonal Variation of Nitrogen Dioxide (NO2) in Lahore, Pakistan

2021 ◽  
Vol 13 (9) ◽  
pp. 4933
Author(s):  
Saimar Pervez ◽  
Ryuta Maruyama ◽  
Ayesha Riaz ◽  
Satoshi Nakai
Keyword(s):  
Land Use ◽  
Air Pollution ◽  
Regression Model ◽  
Urban Areas ◽  
Industrial Development ◽  
Ambient Air ◽  
Ambient Air Pollution ◽  
Land Use Classification ◽  
Land Use Regression ◽  
Air Exposure

Ambient air pollution and its exposure has been a worldwide issue and can increase the possibility of health risks especially in urban areas of developing countries having the mixture of different air pollution sources. With the increase in population, industrial development and economic prosperity, air pollution is one of the biggest concerns in Pakistan after the occurrence of recent smog episodes. The purpose of this study was to develop a land use regression (LUR) model to provide a better understanding of air exposure and to depict the spatial patterns of air pollutants within the city. Land use regression model was developed for Lahore city, Pakistan using the average seasonal concentration of NO2 and considering 22 potential predictor variables including road network, land use classification and local specific variable. Adjusted explained variance of the LUR models was highest for post-monsoon (77%), followed by monsoon (71%) and was lowest for pre-monsoon (70%). This is the first study conducted in Pakistan to explore the applicability of LUR model and hence will offer the application in other cities. The results of this study would also provide help in promoting epidemiological research in future.

scholarly journals Study of Temporal Variations of Equivalent Black Carbon in a Coastal City in Northwest Spain Using an Atmospheric Aerosol Data Management Software

2021 ◽  
Vol 11 (2) ◽  
pp. 516
Author(s):  
María Piñeiro-Iglesias ◽  
Javier Andrade-Garda ◽  
Sonia Suárez-Garaboa ◽  
Soledad Muniategui-Lorenzo ◽  
Purificación López-Mahía ◽  
...  
Keyword(s):  
Data Management ◽  
Black Carbon ◽  
Light Absorption ◽  
Atmospheric Aerosol ◽  
Urban Areas ◽  
Radiative Properties ◽  
Anthropogenic Sources ◽  
Biomass Combustion ◽  
Management Support ◽  
Diurnal Variability

Light-absorbing carbonaceous aerosols (including black carbon (BC)) pose serious health issues and play significant roles in atmospheric radiative properties. Two-year measurements (2015–2016) of aerosol light absorption, combined with measurements of sub-micrometric particles, were continuously conducted in A Coruña (northwest (NW) Spain) to determine their light absorption properties: absorption coefficients (σabs) and the absorption Ångström exponent (AAE). The mean and standard deviation of equivalent black carbon (eBC) during the period of study were 0.85 ± 0.83 µg m−3, which are lower than other values measured in urban areas of Spain and Europe. High eBC concentrations found in winter are associated with an increase in emissions from anthropogenic sources in combination with lower mixing layer heights and frequent stagnant conditions. The pronounced diurnal variability suggests a strong influence from local sources. AAE had an average value of 1.26 ± 0.22 which implies that both fossil fuel combustion and biomass burning influenced optical aerosol properties. This also highlights biomass combustion in suburban areas, where the use of wood for domestic heating is encouraged, as an important source of eBC. All data treatment was gathered using SCALA© as atmospheric aerosol data management support software program.

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