Sains Malaysiana 41(11)(2012): 1335–1344

Assessing and Comparing PM₁₀ Pollutant Behaviour using Functional Data Approach

(Menilai dan Membanding Perilaku Pencemar PM₁₀ dengan Pendekatan Data Fungsi)

Norshahida Shaadan* & Sayang Mohd Deni

Center for Statistical and Decision Science Studies, Faculty of Computer & Mathematical Sciences

40450 UiTM Shah Alam, Selangor D.E. Malaysia

Abd Aziz Jemain

DELTA, School of Mathematical Sciences. Faculty of Science & Technology

Universiti Kebangsaan Malaysia (UKM), 43600, Bangi, Selangor D.E. Malaysia

Received: 4 October 2011 / Accepted: 30 May 2012

ABSTRACT

This study highlights the advantage of functional data approach in assessing and comparing the PM₁₀ pollutant behaviour as an alternative statistical approach during and between the two extreme haze years (1997 and 2005) that have been reported in Selangor, state of Malaysia. The aim of the study was to improvise the current conventional methods used in air quality assessment so that any unforeseen implicit information can be revealed and the previous research findings can be justified. An analysis based on the daily diurnal curves in place of discrete point values was performed. The analysis results provided evidences of the influence of the change in the climate (due to the El-Nino event), the different levels of different emission sources and meteorological conditions on the severity of the PM₁₀ problem. By means of the cummulative exceedence index and the functional depth method, most of the monitoring stations for the year 2005 experienced the worst day of critical exceedences on the 10th of August, while for the year 1997 it occurred between 13th and 26th September inclusively at different dates among the stations.

Keywords: Air quality; behaviour; exceedences; functional data; PM₁₀ pollutant

ABSTRAK

Kajian ini memperlihatkan kelebihan pendekatan data fungsi dalam menilai dan membanding perilaku pencemar PM₁₀ sewaktu dan antara dua tahun jerebu yang paling ekstrim (1997 dan 2005) yang pernah dilaporkan berlaku di negeri Selangor, Malaysia sebagai satu pendekatan alternatif. Tujuan kajian adalah untuk membuat penambahbaikan terhadap kaedah konvensional yang biasa digunakan dalam penilaian dan penaksiran kualiti udara bagi membolehkan maklumat tersirat yang tidak disedari dicungkil dan dapatan daripada kajian lepas dapat diperjelaskan. Analisis dilakukan ke atas data lengkung harian PM₁₀ berdasarkan tempoh mengikut jam bagi menggantikan penggunaan nilai-nilai diskrit titik. Keputusan analisis kajian telah mempamerkan bukti terhadap pengaruh perubahan iklim (ekoran daripada peristiwa El-Nino), perbezaan aras kepekatan berpunca daripada berlainan sumber pelepasan dan keadaan meteorologi terhadap keterukan masalah pencemar udara PM₁₀. Dengan menggunakan indeks kumulatif lebihan dan kaedah kedalaman fungsi, kebanyakan stesen pemantau bagi tahun 2005 didapati mengalami hari yang paling teruk lebihan kritikal kepekatan PM₁₀ pada 10 Ogos manakala pada tahun 1997 berlaku pada tarikh yang berlainan di antara 13 dan 26 September di stesen pemantau yang berbeza.

Kata kunci: Data fungsian; kualiti udara; lebihan; pencemar PM₁₀; perilaku

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*Corresponding author; email: shahida@tmsk.uitm.edu.my