Role of Atmospheric Boundary Layer (ABL) Height and Ventilation Coefficient on Urban Air Quality- A study based on Observations and NWP Model


  • Aditi Singh Ministry of Earth Sciences, New Delhi, India



Air pollution is an issue of great concern in any urban region due to its serious health implications. The capital of India, New Delhi continues to be in the list of most polluted cities since 2014. The air quality of any region depends on the ability of dispersion of air pollutants. The height or depth of the atmospheric boundary layer (ABL) is one measure of dispersion of air pollutants. Ventilation coefficient is another crucial parameter in determining the air quality of any region. Both of these parameters are obtained over Delhi from the operational global numerical weather prediction (NWP) model of National Centre for Medium Range Weather forecasting (NCMRWF) known as NCMRWF Unified Model (NCUM). The height of ABL over Delhi, is also obtained from radiosonde observations using the parcel method. A good agreement is found between the observed and predicted values of ABL height. The maximum height of ABL is obtained during summer season and minimum is obtained in winter season. High values of air pollutants are found when the values of ABL height and ventilation coefficient are low. 


ABL; Ventilation Coefficient; Parcel Method; Air Quality Index; NWP model


[1] Ali, K., Momin, G. A., Tiwari, S., Safai, P. D., Chate, D. M., & Rao, P. S. P.. Fog and precipitation chemistry at Delhi, North India. Atmospheric Environment, 2004, 38: 4215–4222.

[2] Chowdhury, Z., Zheng, M., Schauer, J. J., Sheesley, R. J., Salmon, L. G., Cass, G. R., et al.. Speciation of ambient fine organic carbon particles and source apportionment of PM2.5 in Indian cities. Journal of Geophysical Research, 2007, 112: D15303

[3] CPCB. Central Pollution Control Board. New Delhi: Government of India, 2010.

[4] Dubey, M.. Delhi is India’s Asthma capital. New Delhi: Mail Today, 2009.

[5] Lelieveld, J., Evans, J. S., Fnais, M., Giannadaki, D., and Pozzer, A. The contribution of outdoor air pollution sources to premature mortality on a global scale, Nature, 2015, 525: 367–371.

[6] Gurjar, B. R., van Aardenne, J. A., Lelieveld, J., & Mohan, M. Emission estimates and trends (1990–2000) for megacity Delhi and implications. Atmospheric Environment, 2004, 38: 5663–5681.

[7] Hennumth, B. and Lammert, A. Determination of Atmospheric Boundary Layer height from Radiosonde and Lidar Backscatter, Boundary Layer Meteorology, 2006, 120: 181-200.

[8] Iyer, U. S. and Ernest Raj P. Ventilation coefficients trends in the recent decades over four major Indian metropolitan cities, Journal of Earth System and Science, 2013, 122: 537-549.

[9] Krishnan, P., & Kunhikrishnan, P. K.. Temporal variations of ventilation coefficient at a tropical Indian station using UHF wind profiler. Current Science, 2004, 86: 447–451.

[10] Mahalakshmi, D. V., Sujatha, P., Naidu, C. V., & Chowdary, V. M.. Contribution of vehicular emission on urban air quality: Results from public strike in Hyderabad. Indian Journal of Radio & Space Physics, 2014, 43: 340–348.

[11] Mohan, M., & Kandya, A.. An analysis of the annual and seasonal trends of air quality index of Delhi.Environmental Monitoring and Assessment, 2007, 131: 267–277.

[12] Nair, K. Sandhya, Madhusoodanan, M.S. and Mehajan, R.K. The role of boundary layer height (BLH) variations on pollution dispersion over a coastal station in the southwest peninsular India, 2018.

[13] Reddy, M. S., & Venkataraman, C.. Inventory of aerosol and sulphur dioxide emissions from India: I—Fossil fuel combustion. Atmospheric Environment, 2002, 36: 677–697.

[14] Seibert, P., Beyrich, F., Gryning, S. E., Joffre, S., Rasmussen A., Tercier, P. Review and Intercomparison of Operational Methods for the Determination of the Mixing Height. Atmos. Environ., 2000, 34: 1001–1027.


How to Cite

Singh, A. (2019). Role of Atmospheric Boundary Layer (ABL) Height and Ventilation Coefficient on Urban Air Quality- A study based on Observations and NWP Model. Journal of Atmospheric Science Research, 2(3), 11–16.


Article Type