Document Type: CASE STUDY


1 Department of Mechanical Engineering, Semnan Branch, Islamic Azad University, Semnan, Iran

2 Institute of Internal Combustion Engines and Thermodynamics – IVT, Graz University of Technology, Austria.


The aim of this study is to investigate the problems caused by discharge of polluted air from tunnels into the environment with a specific focus on residential areas. In city tunnels, portal or stacks, pollutant management is a big challenge. Nowadays, air quality management, particularly in urban tunnels, is considered as a part of the ventilation system design. The goal is to see the environmental impacts beforehand. From environmental aspects, preventive measures are required either inside or outside the tunnel in some cases. Niayesh tunnel in Tehran is taken as a case for proving the objectives presented in this study. Concentration of carbon monoxide at the vicinity of the portals is calculated using the proper dispersion simulation. The results of dispersion modeling for the assumed worst case of ventilation can help to understand the environmental impact of ventilation. The worst traffic emissions for a congested traffic scenario,are selected as an emission source for dispersion modeling. According to the traffic condition and fleet composition, the crucial emission extracted from the tunnel is carbon monoxide. Therefore, the performed simulation only focuses on carbon monoxide dispersion modeling. From the other side, carbon monoxide is taken as a demonstration pollutant, because it is inert and chemical reactions can be neglected in short-term considerations. A lagrangian model composed of Graz Lagrangian Model and Graz Mesoscale Model is used for flow-field and dispersion calculations.

Graphical Abstract


  • The study indicated that environmental impact of the discharged carbon monoxide from the Niayesh tunnel is in standard level.
  • According to the distance of the buildings from the portals, the effects of emitted carbon monoxide from the Niayesh tunnel on the surrounding residential areas can be ignored
  • The obtained results are only valid for carbon monoxide with the assumed emission and traffic conditions in the mentioned tunnel.
  • The longitudinal ventilation system is found sufficient for the Niayesh tunnel with the current traffic conditions, and portal air quality management is not required
  • In the case of increase in traffic to more than two lanes or change of fleet composition, another redundant system (air exchange station) might be required.


Main Subjects

Ashrafi, Kh.; Hoshyaripour, A.Gh., (2010). A model to determine atmospheric stability and its correlation with CO concentration. Int. J. Civil Environ. Eng.,  2(2): 83-88 (6 pages).

Brandt, R.; Riess, I., (2009). Possibilities and limitations of tunnel-air filtration and portal-flow extractions. 13th International Symposium on Aerodynamics and Ventilation of Vehicle Tunnels, New Brunswick New Jersey, USA: 13-15 May.

Brousse, B.; Vidal, B.; Ponticq, X.; Goupil, Gh.; Alary, R., (2015). Pollution dispersion at an urban motorwaytunnel portal: Comparison of the small-scale predictive studywith the actual conditions measured on the site. Atmos. Environ., 39: 2459–2473 (18 pages).

Berchet, A.; Zink, K.; Oettl, D.; Brunner, J.; Emmenegger, L.; Brunner, D., (2017a). Evaluation of high-resolution GRAMM–GRAL (v15.12/v14.8) NOx simulations over the city of Zürich, Switzerland, Geosci. Model Dev., 10, 3441-3459 (19 pages).

Berchet, A.; Zink, K.; Müller, C.; Öttl, D.; Brunner, J.; Emmenegger, L.; Brunner, D., (2017b). A cost-effective method for simulation city-wide air flow and pollutant dispersion at building resolving scale. Atmos. Environ., 158, 181-196 (17 pages).

Bakhshizadeh, F.; Rezayan, H.; Akbary, M., (2015). 3D Spatio-Temporal Modeling of NOx Air Pollution of Vehicular Traffic in Vali-e-Asr and Fatemi Streets Intersection, Tehran City. Tehran City. Jsaeh., 2 (1): 43-62 (20 pages).

Broere, W., (2105). Urban underground space: Solving the problems of today’s cities. Tunnell. Undergr. Space Technol., 55: 245–248 (4 pages).

Colberg, C.A.; Tona, B.; Catone, G.; Sangiorgio, C.; Stahel, W.A.; Sturm, P.; Staehelin, J., (2005). Statistical analysis of the vehicle pollutant emissions derived from several European road tunnel studies. Atmos. Environ. 39: 2499 –2511 (13 pages).

Capon, A.; Sheppeard, V.,;Irvine, K.;Jalaudin,B.; Staff ,M.; Marks,G.; Willmore,A, (2008) . Investigating health effects in a community surrounding a road tunnel stack – a cross sectional study. ‎Environ. Health. 7: 46 (10 pages).

Cowie, C.T.;  Rose, N.; Ezz, W.; Xuan, W.; Cortes-Waterman, A.; Belousova, E.; Toelle, B.G.; Sheppeard,V.; Marks, G.B., (2012). Respiratory Health before and after the Opening of a Road Traffic Tunnel: A Planned Evaluation. PLoS ONE, 7(11): e48921 (13 pages).

Cowie, C.T.; Rose, N.; Gillett, R.; Walter, S.; Marks, GB. (2012). Redistribution of traffic related air pollution associated with a new road tunnel. Environ. Sci. Technol., 46: 2918–2927 (10 pages).

Dong, J.;  Tao, Y., Xiao,Y.; Tu, J., (2017). Numerical simulation of pollutant dispersion in urban roadway tunnels. J. Comput. Multiphase Flows, 9(1): 26 – 31 (16 pages).

Gorla, A.; Gianola,G.; Bettelini,M.; Colombo,L, (2008). Air pollution management for the tunnel Lugano.        In: Proceedings of the ITA-AITES World Tunnel Congress. Agra, India Spetember.

Kuykendall, J.R.; Shaw S. L.; Paustenbach, D., Fehling, K.; Kacew, S.; Kabay, V., (2009). Chemicals present in automobile traffic tunnels and the possible community health hazards: A review of the literature, Inhalation Toxicol., 21(9): 747-792 (46 pages).

Kurz, Ch.; Orthofer, R.; Sturm, P.; Kaiser, A.; Uhrner, U.; Reifeltshammer, R.; Rexeis, M., (2014). Projection of the air quality in Vienna between 2005 and 2020 for NO2 and PM10. Urban Climate., 10: 703-719 (17 pages).

Oettl, D.; Sturm, P.; Bacher, M.; Pretterhofer, G.; Almbauer, R., (2002). A simple model for the dispersion of pollutants from a road tunnel portal, Atmos. Environ., 36: 2943–2953 (11 pages).

Oettl, D.; Sturm, P.; Almbauer, R.; Okamoto,S.; Horiuchi,K., (2003a). Dispersion from road tunnel portals: comparison of twodifferent modelling approaches. Atmos. Environ., 37: 5165–5175 (11 pages).

Oettl, D.; Sturm P.J.; Pretterhofer, G.; Bacher, M.;, Rodler, J.; Almbauer R. A., (2003b). Lagrangian Dispersion Modeling of Vehicular Emissions from a Highway in Complex Terrain. J. Air Waste Manage. Assoc., 53: 1233–1240 (8 pages).

Öttl, D.; (2008). Modelling of primary PM10 concentrations for the city of Graz, Austria. Cro. Meteorol. J., 43(1): 375-379 (5 pages).

Öttl, D.; Sturm, P.J.; Almbauer, R.A., (2004). Evaluation of GRAL for the pollutant dispersion from a city street tunnel portal at depressed level. Environ. Model Softw., 20: 499-504 (6 pages).

Öttl, D.; Ferrero, E., (2017). A simple model to assess odour hours for regulatory purposes. Atmos. Environ., 155: 162-173 (12 pages).

Öttl, D.; Kropsch, M.; Mandl, M., (2018). Odour assessment in the vicinity of a pig-fattening farm using field inspections (EN 16841-1) and dispersion modelling. Atmos. Environ., 181: 54-60 (7 pages).

Oettl, D., (2014). High resolution maps of nitrogen dioxide for the Province of Styria, Austria. Int. J. Environ. Pollut., 54(2-4): 137–146 (10 pages).

PIARC, (2008). Road tunnels: a guide to optimising the air quality impact upon the environment. Technical Committee C3.3 Tunnel Operations.

Rafiei, M., (2016). Ventilation and safety of complex tunnel networks in fire cases, Ph.D. dissertation, Institute of thermodynamics and Internal combustion engines. Graz University of Technology publication, Graz, Austria.

Rafiei, M., (2018). Dispersion modelling of Carbon Monoxide Produced by Vehicles - Case Study of Tehran District 2. In  6 th. National Conferecnce of Air Quality Management. Sharif University of Technology, Tehran, Iran, 23-24 January.

Rollings, D.; Parker, N., (2017). Comparison of GRAL wind field with CFD wind fields in a complex urban canyon environment. 23rd Biennal International Clean Air and Environment Conference on the 15-18 October at Pullman Brisbane, 15-18 October.

Sanchez, B.; Santiago, J.; Martilli, A.; Martin, F.; Borge, R.; Quaassdorff, C.; Paz, D., (2017). Modelling NOX concentrations through CFD-RANS in an urban hot-spot using high resolution traffic emissions and meteorology from a mesoscale model. Atmos. Environ., 163: 155-165 (11 pages).

Sturm, P.; Beyer, M.; Rafiei, M., (2017). On the problem of ventilation control in case of a tunnel fire event. Case study:  Fire Saf.., 7: 36-43 (8 pages).

Uhrner, U.; Nöst, T.; Sturm, P., (2016). PM10 non-exhaust emission factors from road tunnel measurements considering deposition and re-suspension, J. Earth Sci. Geotech. Eng., 6 (4): 117-134 (18 pages).

Uhrner, U.; Reifeltshammer, R. ; Sturm, P., (2017). Assessment of No2 concentration levels within a street Canyon and tunnel portal micro environment. 18th International Conference on  Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, Bologna, Italy, 9-12 October.



Rafiei, M.; Sturm, P.J., (2018). Modeling of carbon monoxide dispersion around the urban tunnel portals. Global J. Environ. Sci. Manage., 4(3): … , …

Letters to Editor

GJESM Journal welcomes letters to the editor for the post-publication discussions and corrections which allows debate post publication on its site, through the Letters to Editor. Letters pertaining to manuscript published in GJESM should be sent to the editorial office of GJESM within three months of either online publication or before printed publication, except for critiques of original research. Following points are to be considering before sending the letters (comments) to the editor.

[1] Letters that include statements of statistics, facts, research, or theories should include appropriate references, although more than three are discouraged.
[2] Letters that are personal attacks on an author rather than thoughtful criticism of the author’s ideas will not be considered for publication.
[3] Letters can be no more than 300 words in length.
[4] Letter writers should include a statement at the beginning of the letter stating that it is being submitted either for publication or not.
[5] Anonymous letters will not be considered.
[6] Letter writers must include their city and state of residence or work.
[7] Letters will be edited for clarity and length.