Malaysian Journal of Analytical Sciences Vol 20 No 4 (2016): 863 - 869

DOI: http://dx.doi.org/10.17576/mjas-2016-2004-21

 

 

 

MODELLING DISTRIBUTION FUNCTION OF SURFACE OZONE CONCENTRATION FOR SELECTED SUBURBAN AREAS IN MALAYSIA

 

(Permodelan Fungsi Taburan Kepekatan Permukaan Ozon di Kawasan Sub-Bandar yang Terpilih di Malaysia)

 

Muhammad Izwan Zariq Mokhtar, Nurul Adyani Ghazali*, Muhammad Yazid Nasir, Norhazlina Suhaimi

 

School of Ocean Engineering,

Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia

 

*Corresponding author: nurul.adyani@umt.edu.my

 

 

Received: 24 February 2015; Accepted: 27 October 2015

 

 

Abstract

Ozone is known as an important secondary pollutant in the atmosphere. The aim of this study is to find the best fit distribution for calculating exceedance and return period of ozone based on suburban areas; Perak (AMS1) and Pulau Pinang (AMS2). Three distributions namely Gamma, Rayleigh and Laplace were used to fit 2 years ozone data (2010 and 2011). The parameters were estimated by using Maximum Likelihood Estimation (MLE) in order to plot probability distribution function (PDF) and cumulative distribution function (CDF). Four performance indicators were used to find the best distribution namely, normalized absolute error (NAE), prediction accuracy (PA), coefficient of determination (R²) and root mean square error (RMSE). The best distribution to represent ozone concentration at both sites in 2010 and 2011 is Gamma distribution with the smallest error measure (NAE and RMSE) and the highest adequacy measure (PA and R²). For the 2010 data, AMS1 was predicted to exceed 0.1 ppm for 2 days in 2011 with a return period of one occurrence per 179 days. However, AMS2 do not exceed MAAQG limit (0.1 ppm) based on both 2010 and 2011. From the results, the exceedance and return period can be used as a guidance to overcome future air pollution problem.

 

Keywords:  ozone, performance indicators, probability distribution function, return period, cumulative distribution function

 

Abstrak

Ozon dikenali sebagai pencemar sekunder yang paling penting di atmosfera. Matlamat kajian ini adalah untuk mengenalpasti taburan yang terbaik dalam mengira jumlah kepekatan yang melepasi had yang ditetapkan dan tempoh kembali untuk ozon berdasarkan kawasan sub-bandar; Perak (AMS1) dan Pulau Pinang (AMS2). Pembolehubah – pemboleubah telah dianggarkan melalui penggunaan penganggar kebolehjadian maksimum (MLE) untuk plot fungsi taburan kebarangkalian (PDF) dan fungsi taburan kumulatif (CDF). 4 penunjuk prestasi telah digunakan untuk mencari taburan terbaik antaranya, ralat mutlak dinormalkan (NAE), kejituan ramalan (PA)’, pekali penentuan (R²)’ dan punca min ralat kuasa dua (RMSE). Taburan terbaik yang mewakili kepekatan ozon  di kedua – dua tempat adalah taburan Gamma dengan nilai ukuran ralat yang terkecil (NAE dan RMSE) dan nilai ukur kadaran yang terbesar (PA dan R²). Data bagi tahun 2010, AMS1 dijangkakan akan melepasi had 0.1 ppm dalam masa 2 hari pada tahun 2011 dengan tempoh kembali satu kejadian dalam masa 179 hari. Walaubagaimanapun, AMS2 tidak melebihi had MAAQG (0.01 ppm) untuk kedua – dua tahun 2010 dan 2011. Berdasarkan hasil kajian, didapati jumlah kepekatan yang melepasi had yang ditetapkan dan tempoh kembali boleh digunakan sebagai panduan untuk mengatasi masalah pencemaran udara pada masa akan datang.

 

Kata kunci:  ozon, penunjuk prestasi, fungsi taburan kebarangkalian, fungsi taburan kumulatif, tempoh kembali

 

References

1.       Yusof, N. F. F. M., Ramli, N. A., Yahaya, A. S., Sansuddin, N., Ghazali, N. A. and Madhoun, W. A. (2010). Monsoonal differences and probability distribution of PM₁₀ concentration.  Environmental Monitoring and Assessment, 163: 655 – 667.

2.       Wallace, J. M. and Hobbs, P.V. (2006). Atmospheric Science. Academic Press Publication, 2: 153 – 198.

3.       Ramli, N. A., Ghazali, N. A. and Yahaya, A. S. (2010). Diurnal fluctuations of ozone concentrations and its precursors and prediction of ozone using multiple linear regressions. Malaysia Journal of Environmental Management, 11(2): 57 – 69.

4.       Banan, N., Latif, M.T. and Juneng, L. (2013). An assessment of ozone levels in typical urban areas in the Malaysian Peninsular. International Journal of Environmental, Earth Science and Technology, 7(2): 61 – 64.

5.       Ahamad, F., Latif, M.T., Tang, R., Juneng, L., Dominick, D. and Juahir, H. (2014). Variation of surface ozone exceedance around Klang Valley, Malaysia. Journal of Atmospheric Research, 139: 116 – 127.

6.       Ismail, A. S., Latif, M. T., Azmi, S. Z., Juneng, L. and Jemain, A. A. (2010). Variation of surface ozone recorded at the eastern coastal region of the Malaysian Peninsula. American Journal of Environmental Sciences, 6(6): 560 – 569.

7.       Department of Environment, Ministry of Natural Resources and Environment (2012). Malaysia environmental quality report. ISSN 0127 – 6433.

8.       Forbes, C., Evans, M., Hastings, N. and Peacock, B. (2010). Statistical Distributions. Wiley, 4: 109 – 176.

9.       Noor, N. M., Tan, C., Ramli, N. A., Yahaya, A. S. and Yusof, N. F. F. M. (2011). Assessment of various probability distributions to model PM₁₀ concentration for industrialized area in Peninsula Malaysia: A case study in Shah Alam and Nilai. Australian Journal of Basic and Applied Sciences, 5(12): 2796 – 2811.

10.    Lu, H.C. (2003). Estimating the emission source reduction of PM₁₀ in Central Taiwan. Journal of Chemosphere, 54: 805 – 814.

11.    Ul-Saufie, A. Z., Yahaya, A. S., Ramli, N. A. and Hamid, H.A. (2012). Robust regression models for predicting PM₁₀ concentration in an industrial area. International Journal of Engineering and Technology, 2(3): 364 – 370.

12.    Sansuddin, N., Ramli, N. A., Yahaya, A. S., Yusof, N. F. F. M., Ghazali, N. A. and Madhoun, W. A. A. (2011). Statistical analysis of PM₁₀ concentrations at different locations in Malaysia. Environmental Monitoring Assessment, 180: 573 – 588.