Sources and concentration of nanoparticles (< 10 nm diameter) in the urban atmosphere (original) (raw)
Related papers
Remarkable dynamics of nanoparticles in the urban atmosphere
Atmospheric Chemistry and Physics, 2011
Nanoparticles emitted from road traffic are the largest source of respiratory exposure for the general public living in urban areas. It has been suggested that the adverse health effects of airborne particles may scale with the airborne particle number, which if correct, focuses attention on the nanoparticle (less than 100 nm) size range which 5 15 of sub-50 nm particles at the BT Tower during days affected by higher turbulence as determined by Doppler Lidar measurements and indicate a loss of nanoparticles from air aged during less turbulent conditions. These results suggest that nanoparticles are lost by evaporation, rather than coagulation processes. The results have major implications for understanding the impacts of traffic-generated particulate matter on human 20 health.
Contribution of traffic-originated nanoparticle emissions to regional and local aerosol levels
2021
Sub-50 nm particles originating from traffic emissions pose risks to human health due to their high lung deposition efficiency and potentially harmful chemical composition. We present a modeling study using an updated European Aerosol Cloud Climate and Air Quality Interactions (EUCAARI) number emission inventory, incorporating a more realistic, empirically justified particle size distribution (PSD) for sub-50 nm particles from road traffic as compared with the previous version. We present experimental PSDs and CO 2 concentrations, measured in a highly trafficked street canyon in Helsinki, Finland, as an emission factor particle size distribution (EFPSD), which was then used in updating the EUCAARI inventory. We applied the updated inventory in a simulation using the regional chemical transport model PMCAMx-UF over Europe for May 2008. This was done to test the effect of updated emissions at regional and local scales, particularly in comparison with atmospheric new particle formation (NPF). Updating the inventory increased the simulated average total particle number concentrations by only 1 %, although the total particle number emissions were increased to a 3-fold level. The concentrations increased up to 11 % when only 1.3-3 nm sized particles (nanocluster aerosol, NCA) were considered. These values indicate that the effect of updating overall is insignificant at a regional scale during this photochemically active period. During this period, the fraction of the total particle number originating from atmospheric NPF processes was 91 %; thus, these simulations give a lower limit for the contribution of traffic to the aerosol levels. Nevertheless, the situation is different when examining the effect of the update closer spatially or temporally or when focusing on the chemical composition or the origin of the particles. For example, the daily average NCA concentrations increased by a factor of several hundred or thousand in some locations on certain days. Overall, the most significant effects-reaching several orders of magnitude-from updating the inventory are observed when examining specific particle sizes (especially 7-20 nm), particle components, and specific urban areas. While the model still has a tendency to predict more sub-50 nm particles compared to the observations, the most notable underestimations in the concentrations of sub-10 nm particles are now overcome. Additionally, the simulated distributions now agree better with the data observed at locations with high traffic densities. The findings of this study highlight the need to consider emissions, PSDs, and composition of sub-50 nm particles from road traffic in studies focusing on urban air quality. Updating this emission source brings the simulated aerosol levels, particularly in urban locations, closer to observations, which highlights its importance for calculations of human exposure to nanoparticles.
Atmospheric Environment, 2010
The likely health and environmental implications associated with atmospheric 9 nanoparticles have prompted considerable recent research activity. Knowledge of the 10 characteristics of these particles has improved considerably due to an ever growing interest in 11 the scientific community, though not yet sufficient to enable regulatory decision making on a 12 particle number basis. This review synthesizes the existing knowledge of nanoparticles in the 13 urban atmosphere, highlights recent advances in our understanding and discusses research 14 priorities and emerging aspects of the subject. The article begins by describing the 15 characteristics of the particles and in doing so treats their formation, chemical composition 16 and number concentrations, as well as the role of removal mechanisms of various kinds. This 17 is followed by an overview of emerging classes of nanoparticles (i.e. manufactured and bio-18 fuel derived), together with a brief discussion of other sources. The subsequent section 19 provides a comprehensive review of the working principles, capabilities and limitations of the 20 main classes of advanced instrumentation that are currently deployed to measure number and 21 size distributions of nanoparticles in the atmosphere. A further section focuses on the 22 dispersion modelling of nanoparticles and associated challenges. Recent toxicological and 23 epidemiological studies are reviewed so as to highlight both current trends and the research 24 needs relating to exposure to particles and the associated health implications. The review then 25 addresses regulatory concerns by providing an historical perspective of recent developments 26 together with the associated challenges involved in the control of airborne nanoparticle 27
Traffic is a major source of atmospheric nanocluster aerosol
Proceedings of the National Academy of Sciences, 2017
Significance We report the significant presence of traffic-originated nanocluster aerosol (NCA) particles in a particle diameter range of 1.3–3.0 nm of urban air, determine the emission factors for the NCA, and evaluate its global importance. Our findings are important because they significantly update the current understanding of atmospheric aerosol in urban areas. They demonstrate that in urban air, extremely small particles form a significant fraction of the total particle number and are a direct result of anthropogenic emissions, that is, the emissions from road traffic. Thus, our findings also imply that in urban areas, an atmospheric nucleation process is not necessary for the formation of a large number of particles that affect population health and climate.
A study of nanoparticle sizes and their distributions aerosols along the road in Ulaanbaatar city
2012 7th International Forum on Strategic Technology (IFOST), 2012
Particle sizes and their distributions of aerosols along the road in Ulaanbaatar city were studied by Photon Cross Correlation Spectroscopy (PCCS) NANOPHOX (Sympatec GmbH, Germany). Mean diameter (x 0), size distribution range, specific surface area (Sv) of aerosol particles are equal to 1.1÷2.5μm, 74nm÷4.0μm and 2.38÷5.43m 2 /cm 3 respectively. On the other hand, particles distribution is Gaussian with density 0.02÷8.15 (q 3 lg) in the range of 790nm÷3.8μm. However, nanoparticles with diameters less than 74nm were not observed. The results reveal that samples contain 0.02% (volume persent) ultrafine particles or nanoparticles occur in the range of 74-100nm, 83.73% fine particles (PM2.5) occur in the range of 100nm÷2.4μm and 16.25% coarse particles (PM10) occur in the range of 2.4-4.0μm. It can be concluded that road aerosol sample contain high percent of PM2.5 particles.
Dispersion of a Traffic Related Nanocluster Aerosol Near a Major Road
Atmosphere, 2019
Traffic is a major source of ultrafine aerosol particles in urban environments. Recent studies show that a significant fraction of traffic-related particles are only few nanometers in diameter. Here, we study the dispersion of this nanocluster aerosol (NCA) in the size range 1.3–4 nm. We measured particle concentrations near a major highway in the Helsinki region of Finland, varying the distance from the highway. Additionally, modelling studies were performed to gain further information on how different transformation processes affect NCA dispersion. The roadside measurements showed that NCA concentrations fell more rapidly than the total particle concentrations, especially during the morning. However, a significant amount of NCA particles remained as the aerosol population evolved. Modelling studies showed that, while dilution is the main process acting on the total particle concentration, deposition also had a significant impact. Condensation and possibly enhanced deposition of NC...
Nanoparticle emissions from 11 non-vehicle exhaust sources – A review
Atmospheric Environment, 2013
Nanoparticle emissions from road vehicles have been studied extensively in the recent past due to their dominant contribution towards the total airborne particle number concentrations (PNCs) found in the urban atmospheric environment. In view of upcoming tighter vehicle emission standards and adoption of cleaner fuels in many parts of the world, the contribution to urban nanoparticles from non-vehicle exhaust sources (NES) may become more pronounced in future. As of now, only limited information exists on nanoparticle emissions from NES through the discretely published studies. This article presents critically synthesised information in a consolidated manner on 11 NES (i.e. roadtyre interaction, construction and demolition, aircraft, ships, municipal waste incineration, power plants, domestic biomass burning, forest fires, cigarette smoking, cooking, and secondary formation). Source characteristics and formation mechanisms of nanoparticles emitted from each NES are firstly discussed, followed by their emission strengths, airborne concentrations and physicochemical characteristics. Direct comparisons of the strengths of NES are not straightforward but an attempt has been made to discuss their importance relative to the most prominent source (i.e. road vehicles) of urban nanoparticles. Some interesting comparisons emerged such as 1 kg of fast and slow wood burning produces nearly the same number of particles as for each km driven by a heavy duty vehicle (HDV) and a light duty vehicle, respectively. About 1 minutes of cooking on gas can produce the similar particle numbers generated by ~10 minutes of cigarette smoking or 1 m travel by a HDV. Apportioning the contribution of numerous sources from the bulk measured airborne PNCs is essential for determining their relative importance. Receptor modelling methods for estimation of source emission contributions are discussed. A further section evaluates the likely exposure risks, health and regulatory implications associated with each NES. It is concluded that much research is needed to provide adequate quantification of all nanoparticle sources, and to establish the relative toxicity of nanosize particles from each.
2011
15 Reducing exposure to atmospheric nanoparticles in urban areas is important for 16 protecting public health. Developing new or improving the capabilities of existing 17 dispersion models will help to design effective mitigation strategies for nanoparticle 18 rich environments. The aims of this review are to summarise current practices of 19 nanoparticle dispersion modelling at five local scales (i.e. vehicle wake, street 20 canyons, neighbourhood, city and road tunnels), together with highlighting associated 21 challenges, research gaps and priorities. The review begins with a synthesis of 22