Nordic Envicon Oy

Helsinki, Finland

Nordic Envicon Oy

Helsinki, Finland

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Denby B.R.,Norwegian Institute For Air Research | Sundvor I.,Norwegian Institute For Air Research | Johansson C.,University of Stockholm | Johansson C.,Environment and Health Protection Administration | And 7 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.


Denby B.R.,Norwegian Institute For Air Research | Sundvor I.,Norwegian Institute For Air Research | Johansson C.,University of Stockholm | Johansson C.,Environment and Health Protection Administration of the City of Stockholm | And 8 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.


Kauhaniemi M.,Finnish Meteorological Institute | Stojiljkovic A.,Nordic Envicon Oy | Pirjola L.,Helsinki Metropolia University of Applied Sciences | Karppinen A.,Finnish Meteorological Institute | And 8 more authors.
Atmospheric Chemistry and Physics | Year: 2014

The predictions of two road dust suspension emission models were compared with the on-site mobile measurements of suspension emission factors. Such a quantitative comparison has not previously been reported in the reviewed literature. The models used were the Nordic collaboration model NORTRIP (NOn-exhaust Road TRaffic Induced Particle emissions) and the Swedish-Finnish FORE model (Forecasting Of Road dust Emissions). These models describe particulate matter generated by the wear of road surface due to traction control methods and processes that control the suspension of road dust particles into the air. An experimental measurement campaign was conducted using a mobile laboratory called SNIFFER, along two selected road segments in central Helsinki in 2007 and 2008. The suspended PM10 concentration was measured behind the left rear tyre and the street background PM10 concentration in front of the van. Both models reproduced the measured seasonal variation of suspension emission factors fairly well during both years at both measurement sites. However, both models substantially under-predicted the measured emission values. The article illustrates the challenges in conducting road suspension measurements in densely trafficked urban conditions, and the numerous requirements for input data that are needed for accurately applying road suspension emission models.


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.


Kupiainen K.,Nordic Envicon Oy | Kupiainen K.,Finnish Environment Institute | Ritola R.,Nordic Envicon Oy | Stojiljkovic A.,Nordic Envicon Oy | And 4 more authors.
Atmospheric Environment | Year: 2016

The aim of this study was to determine the relative contributions of mineral dust sources, particularly pavement wear and traction sanding in the PM10 samples collected from 1) street side ambient air and 2) street dust suspension emission samples. The study was conducted between autumn 2011 and spring 2012 at Suurmetsäntie in Helsinki, Finland. The results showed that dust from pavement aggregates was the largest source during spring, accounting for 40–50 percent of the particulate matter in the air and suspension samples. Based on studies on formation of dust, major source of the dust from pavement aggregates is the wear by studded tyres. Traction sanding (1–5.6 mm wet sieved crushed stone) and road salting (NaCl) were applied frequently during the winter 2011/2012. Sanding material explained about 25 percent of the street dust in the air and suspension samples. Traction sanding is estimated to account for approximately few percent of the pavement dust via “the sandpaper effect”. Effect of road salt was few percent in the samples. The source contributions from pavement and traction sanding observed in spring 2012 at Suurmetsäntie are similar to what has been estimated in a previous study conducted in the early 2000s in Finland. The general perception in Finland has been that traction sanding is the main source of airborne street dust. Studies conducted in 2000s and the results of this study, however, indicate that traction sanding has been an important but not the main source of dust in PM10 even in winters with extensive use of sanding for traction control. © 2016 Elsevier Ltd


Denby B.R.,Norwegian Meteorological Institute | Ketzel M.,University of Aarhus | Ellermann T.,University of Aarhus | Stojiljkovic A.,Nordic Envicon Oy | And 9 more authors.
Atmospheric Environment | Year: 2016

De-icing of road surfaces is necessary in many countries during winter to improve vehicle traction. Large amounts of salt, most often sodium chloride, are applied every year. Most of this salt is removed through drainage or traffic spray processes but a certain amount may be suspended, after drying of the road surface, into the air and will contribute to the concentration of particulate matter. Though some measurements of salt concentrations are available near roads, the link between road maintenance salting activities and observed concentrations of salt in ambient air is yet to be quantified. In this study the NORTRIP road dust emission model, which estimates the emissions of both dust and salt from the road surface, is applied at five sites in four Nordic countries for ten separate winter periods where daily mean ambient air measurements of salt concentrations are available. The model is capable of reproducing many of the salt emission episodes, both in time and intensity, but also fails on other occasions. The observed mean concentration of salt in PM10, over all ten datasets, is 4.2 μg/m3 and the modelled mean is 2.8 μg/m3, giving a fractional bias of −0.38. The RMSE of the mean concentrations, over all 10 datasets, is 2.9 μg/m3 with an average R2 of 0.28. The mean concentration of salt is similar to the mean exhaust contribution during the winter periods of 2.6 μg/m3. The contribution of salt to the kerbside winter mean PM10 concentration is estimated to increase by 4.1 ± 3.4 μg/m3 for every kg/m2 of salt applied on the road surface during the winter season. Additional sensitivity studies showed that the accurate logging of salt applications is a prerequisite for predicting salt emissions, as well as good quality data on precipitation. It also highlights the need for more simultaneous measurements of salt loading together with ambient air concentrations to help improve model parameterisations of salt and moisture removal processes. © 2016 The Authors


Pirjola L.,Helsinki Metropolia University of Applied Sciences | Johansson C.,University of Stockholm | Kupiainen K.,Nordic Envicon Oy | Stojiljkovic A.,Nordic Envicon Oy | And 3 more authors.
Journal of the Air and Waste Management Association | Year: 2010

Very few real-world measurements of road dust suspension have been performed to date. This study compares two different techniques (referred to as Sniffer and Emma) to measure road dust emissions. The main differences between the systems are the construction of the inlet, different instruments for recording particulate matter (PM) levels, and different loads on the wheel axes (the weight of Sniffer was much higher than that of Emma). Both systems showed substantial small-scale variations of emission levels along the road, likely depending on-road surface conditions. The variations observed correlated quite well, and the discrepancies are likely a result of variations in dust load on the road surface perpendicular to the driving direction that cause variations in the measurements depending on slightly different paths driven by the two vehicles. Both systems showed a substantial influence on the emission levels depending on the type of tire used. The summer tire showed much lower suspension than the winter tires (one nonstudded and one studded). However, the relative importance of the nonstudded versus studded tire was rather different. For the ratio of studded/nonstudded, Emma shows higher values on all road sections compared with Sniffer. Both techniques showed increased emission levels with increasing vehicle speed. When the speed increased from 50 to 80 km hr/1, the relative concentrations increased by 30-170% depending on the tire type and dust load. However, for road sections that were very dirty, Sniffer showed a much higher relative increase in the emission level with the nonstudded tire. Sniffer's absolute concentrations were mostly higher than Emma's. Possible reasons for the differences are discussed in the paper. Both systems can be used for studying relative road dust emissions and for designing air quality management strategies. Copyright © 2010 Air & Waste Management Association.


Kupiainen K.J.,Nordic Envicon Oy | Kupiainen K.J.,International Institute For Applied Systems Analysis | Pirjola L.,Helsinki Metropolia University of Applied Sciences | Pirjola L.,University of Helsinki
Atmospheric Environment | Year: 2011

In Northern cities respirable street dust emission levels (PM10) are especially high during spring. The spring time dust has been observed to cause health effects as well as discomfort among citizens. Major sources of the dust are the abrasion products from the pavement and traction sand aggregates that are formed due to the motion of the tyre. We studied the formation of respirable abrasion particles in the tyre-road interface due to tyre studs and traction sanding by a mobile laboratory vehicle Sniffer. The measurements were preformed on a test track, where the influence of varying stud weight and stud number per tyre on PM10 emissions was studied. Studded tyres resulted in higher emission levels than studless tyres especially with speeds 50 km h-1 and higher; however, by using light weight studs, which approximately halves the weight of studs, or by reducing the number of studs per tyre to half, the emission levels decreased by approximately half. Additionally measurements were done with and without traction sand coverage on the pavement of a public road. After traction sanding the emission levels were not affected by tyre type but by formation and suspension of traction sand related dust from the road surface. The emissions after traction sanding decreased as a function of time as passing vehicles' motion shifted the sand grains away from the areas with most tyre-road contact. © 2011 Elsevier Ltd.


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.


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.

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