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Helsinki, Finland

Denby B.R.,Norwegian Institute For Air Research | Sundvor I.,Norwegian Institute For Air Research | Johansson C.,University of Stockholm | Pirjola L.,Helsinki Metropolia University of Applied Sciences | And 6 more authors.
Atmospheric Environment | Year: 2013

Non-exhaust traffic induced emissions are a major source of particle mass in most European countries. This is particularly important in Nordic and Alpine countries where winter time road traction maintenance occurs, e.g. salting and sanding, and where studded tyres are used. In this paper, Part 1, the road dust sub-model of a coupled road dust and surface moisture model (NORTRIP) is described. The model provides a generalised process based formulation of the non-exhaust emissions, with emphasis on the contribution of road wear, suspension, surface dust loading and the effect of road surface moisture (retention of wear particles and suspended emissions). The model is intended for use as a tool for air quality managers to help study the impact of mitigation measures and policies. We present a description of the road dust sub-model and apply the model to two sites in Stockholm and Copenhagen where seven years of data with surface moisture measurements are available. For the site in Stockholm, where studded tyres are in use, the model predicts the PM10 concentrations very well with correlations (R2) in the range of R2=0.76-0.91 for daily mean PM10. The model also reproduces well the impact of a reduction in studded tyres at this site. For the site in Copenhagen the correlation is lower, in the range 0.44-0.51. The addition of salt is described in the model and at both sites this leads to improved correlations due to additional salt emissions. For future use of the model a number of model parameters, e.g. wear factors and suspension rates, still need to be refined. The effect of sanding on PM10 emissions is also presented but more information will be required before this can be confidently applied for management applications. © 2013 Elsevier Ltd. Source


Denby B.R.,Norwegian Institute For Air Research | Sundvor I.,Norwegian Institute For Air Research | Johansson C.,University of Stockholm | Pirjola L.,Helsinki Metropolia University of Applied Sciences | And 7 more authors.
Atmospheric Environment | Year: 2013

Non-exhaust traffic induced emissions are a major source of airborne particulate matter in most European countries. This is particularly important in Nordic and Alpine countries where winter time road traction maintenance occurs, e.g. salting and sanding, and where studded tyres are used. Though the total mass generated by wear sources is a key factor in non-exhaust emissions, these emissions are also strongly controlled by surface moisture conditions. In this paper, Part 2, the road surface moisture sub-model of a coupled road dust and surface moisture model (NORTRIP) is described. We present a description of the road surface moisture part of the model and apply the coupled model to seven sites in Stockholm, Oslo, Helsinki and Copenhagen over 18 separate periods, ranging from 3.5 to 24 months. At two sites surface moisture measurements are available and the moisture sub-model is compared directly to these observations. The model predicts the frequency of wet roads well at both sites, with an average fractional bias of-2.6%. The model is found to correctly predict the hourly surface state, wet or dry, 85% of the time. From the 18 periods modelled using the coupled model an average absolute fractional bias of 15% for PM10 concentrations was found. Similarly the model predicts the 90'th daily mean percentiles of PM10 with an average absolute bias of 19% and an average correlation (R2) of 0.49. When surface moisture is not included in the modelling then this average correlation is reduced to 0.16, demonstrating the importance of the surface moisture conditions. Tests have been carried out to assess the sensitivity of the model to model parameters and input data. The model provides a useful tool for air quality management and for improving our understanding of non-exhaust traffic emissions. © 2013 The Authors. Source


Wang Y.,Aalto University | Pelkonen M.,Aalto University | Kotro M.,Nordic Envicon Oy
Water, Air, and Soil Pollution | Year: 2010

Composting municipal wastewater sludge may generate composting wastewater (acid washer water and tunnel wastewater) with high ammonium-nitrogen (NH 4-N) concentration; this kind of wastewater is usually generated in a rather small daily amount. A procedure of air stripping with catalytic oxidation was developed and tested with pilot-scale and full-scale units for synthetic disposal of the high NH4-N wastewaters from composting facilities. In air stripping, around 90% NH4-N removal efficiency was reliably achieved with a maximum of 98%. A model to describe the stripping process efficiency was constructed, which can be used for process optimization. After catalytic oxidation, the concentrations in the outlet gas were acceptable for NH3, NOX, NO2, and N2O, but the NH3 and N2O concentrations limited the feasible loading range. The treatment costs were estimated in detail. The results indicate that air stripping with the catalytic oxidation process can be applied for wastewater treatment in composting facilities. © 2009 Springer Science+Business Media B.V. Source


Harkonen J.,Finnish Meteorological Institute | Pirjola L.,Helsinki Metropolia University of Applied Sciences | Kupiainen K.,Nordic Envicon Oy | Kauhaniemi M.,Finnish Meteorological Institute | And 2 more authors.
HARMO 2011 - Proceedings of the 14th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes | Year: 2011

We have studied the influence of vehicle speed and meteorological variables on the detected non-exhaust particulate signals by a mobile monitoring system called the Sniffer in the measurement campaign during 2006-2009, in Helsinki. PM10 particulates are decomposed into coarse and fine fractions. The functional forms based on the statistically analyzed data, reveal the dependency of emission factors on vehicle speed and meteorological variables. A clear dependence of the coarse fraction on vehicle velocity is observed and the threshold velocity for the change of slopes of the emission factors and for the relative coarse fraction is suggested. Source


Denby B.R.,Norwegian Institute For Air Research | Sundvor I.,Norwegian Institute For Air Research | Johansson C.,University of Stockholm | Kauhaniemi M.,Finnish Meteorological Institute | And 10 more authors.
HARMO 2011 - Proceedings of the 14th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes | Year: 2011

Non-exhaust traffic induced emissions are a major source of particle mass in most European countries. This is particularly important in Nordic and Alpine countries where winter time road traction maintenance occurs, e.g. salting and sanding, and where studded tyres are used. Modelling these emissions is a challenging task as they are sensitive to environmental factors such as road surface moisture as well as road maintenance activities (salting and sanding) and tyre and vehicle types. The ability to model these emissions is desirable as this provides the potential for more effective road management, improved assessment of mitigation strategies for reducing emissions and can help quantify the impact of salting and sanding activities. These are all important applications relevant to the European AQ Directive. The Nordic based project NORTRIP is building upon existing road dust emission models, combined with field and laboratory measurements, to develop a more comprehensive and generalised process based model description of the non-exhaust emissions, with emphasis on the contribution of road wear, salt and sand to the emissions. In this paper we present the current status of the modelling, briefly describing the processes and their parameterisations. The performance of the model is illustrated using two example applications from Norway and Sweden and future developments are discussed. Source

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