33 Characteristics and Mitigation of Vehicular Non-Exhaust …
215
33.4 Conclusions
The non-exhaust emission factors are influenced by weather, especially the road
surface moisture, and have seasonal peaks particularly in winter and spring, due to
enhanced formation of layers of street dust and their suspension to the air. Results
demonstrated that changes in the selection of winter tyre types and their use, as
well as road maintenance interventions could substantially reduce the non-exhaust
emissions, especially in spring. We experienced challenges in developing relevant
input datasets for the model in many parts of the country and further work should
focus on filling the data gaps. The methods presented in this study could be used at
least in the whole Northern part of the world, i.e., the Nordic countries and Northern
Central Europe, Northern Russia, North America, and parts of China and Japan.
Questions and answers:
Questioner 1: Peter Jackson
Question 1: Have you considered the size distribution of traction material applied to
roads? Specifically the percent silt content?
Answer 1: Yes, the model includes the size distribution and the silt content of the
traction material as a source of particulate matter.
Questioner 2: Cristina Guerreiro
Question 2: Does the NOTRTIP model take into account the type of asphalt for
estimating asphalt wear and wear emissions?
Answer 2: Yes, the user can fill in parameters of asphalt properties related to grain
size distribution and durability of the aggregate to the model and these affect the
wear rate and subsequent emissions.
Questioner 3: David Niemi
Question 3: What specifically was talked about? Specifically resuspension of surface
material into the air?
Answer 3: The talk and the paper is particularly about emissions of PM 10 and PM 2.5
from non-exhaust sources to the air. The methodology includes both direct and suspension/resuspension emission pathways. However, in Finnish conditions specifically resuspension emissions are significant and key in explaining the high PM
concentrations in the spring period.
Question 4: Is removal of particles through settling & impaction on snowbanks, trees,
buildings included?
Answer 4: NORTRIP is an emission model. Apart from the suspension removal
mechanism, particles are removed from the road surface through drainage, by vehicle
spray and during snow removal. Accumulation in snow banks or trees outside the road
surface is not included. Any deposition processes outside the road surface system
are not part of the emission model.
Acknowledgements This work has been funded by the Academy of Finland in the project Environmental impact assessment of airborne particulate matter: the effects of abatement and management
strategies (BATMAN) and NordForsk under the Nordic Programme on Health and Welfare Project
#75007: Understanding the link between air pollution and distribution of related health impacts and
welfare in the Nordic countries (NordicWelfAir).
215
33.4 Conclusions
The non-exhaust emission factors are influenced by weather, especially the road
surface moisture, and have seasonal peaks particularly in winter and spring, due to
enhanced formation of layers of street dust and their suspension to the air. Results
demonstrated that changes in the selection of winter tyre types and their use, as
well as road maintenance interventions could substantially reduce the non-exhaust
emissions, especially in spring. We experienced challenges in developing relevant
input datasets for the model in many parts of the country and further work should
focus on filling the data gaps. The methods presented in this study could be used at
least in the whole Northern part of the world, i.e., the Nordic countries and Northern
Central Europe, Northern Russia, North America, and parts of China and Japan.
Questions and answers:
Questioner 1: Peter Jackson
Question 1: Have you considered the size distribution of traction material applied to
roads? Specifically the percent silt content?
Answer 1: Yes, the model includes the size distribution and the silt content of the
traction material as a source of particulate matter.
Questioner 2: Cristina Guerreiro
Question 2: Does the NOTRTIP model take into account the type of asphalt for
estimating asphalt wear and wear emissions?
Answer 2: Yes, the user can fill in parameters of asphalt properties related to grain
size distribution and durability of the aggregate to the model and these affect the
wear rate and subsequent emissions.
Questioner 3: David Niemi
Question 3: What specifically was talked about? Specifically resuspension of surface
material into the air?
Answer 3: The talk and the paper is particularly about emissions of PM 10 and PM 2.5
from non-exhaust sources to the air. The methodology includes both direct and suspension/resuspension emission pathways. However, in Finnish conditions specifically resuspension emissions are significant and key in explaining the high PM
concentrations in the spring period.
Question 4: Is removal of particles through settling & impaction on snowbanks, trees,
buildings included?
Answer 4: NORTRIP is an emission model. Apart from the suspension removal
mechanism, particles are removed from the road surface through drainage, by vehicle
spray and during snow removal. Accumulation in snow banks or trees outside the road
surface is not included. Any deposition processes outside the road surface system
are not part of the emission model.
Acknowledgements This work has been funded by the Academy of Finland in the project Environmental impact assessment of airborne particulate matter: the effects of abatement and management
strategies (BATMAN) and NordForsk under the Nordic Programme on Health and Welfare Project
#75007: Understanding the link between air pollution and distribution of related health impacts and
welfare in the Nordic countries (NordicWelfAir).