Browsing by Author "Justin Sentian"

Now showing 1 - 4 of 4
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    Application of K-Means Clustering and Calendar View Visualisation for Air Pollution Index Analysis
    (IOP Publishing, 2022) Z Ali Omar; Siti Rahayu Mohd Hashim; Justin Sentian; Su Na Chin
    Two years of diurnal concentration of particulate matter (PM10) and nitrogen dioxide with the addition of relative humidity measurement, collected from Putrajaya, Malaysia's ground-based measurement station from January 2014 to December 2015, were analysed. K-means clustering was employed and optimal clusters of four were identified for each year based on the most suggested number of clusters from internal cluster validation measures of the total within sum of square, silhouette index and gap statistics. Each cluster was then profiled where each mean pollutant sub-indices were calculated and the contributing pollutant to the air pollution index (API) was determined by looking at the maximum value from all sub-indices. This mechanism closely follows the Recommended Malaysian Air Quality Guidelines (RMG) for determining API.
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    BTEX compositions and its potential health impacts in Malaysia
    (Elsevier, 2019) Mohd Talib Latif; Fatimah Ahamad; Md Firoz Khan; Mohd Shahrul Mohd Nadzir; Murnira Othman; Mazrura Sahani; Muhammad Ikram Abdul Wahab; Noorlin Mohamad; Royston Uning; Seng Chee Poh; Muhammad Fais Fadzil; Justin Sentian; Norhayati Md Tahir; Haris Hafizal Abd Hamid
    This study aims to determine the composition of BTEX (benzene, toluene, ethylbenzene and xylene) and assess the risk to health at different sites in Malaysia. Continuous monitoring of BTEX in Kuala Lumpur City Centre, Kuala Terengganu, Kota Kinabalu and Fraser Hill were conducted using Online Gas Chromatograph.
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    Carbon monoxide 'hot-spots' in urban area of Kota Kinabalu City, Sabah
    (UMS, 2015) Justin Sentian; Ong Pei Tze
    Air dispersion models have been widely used to address air quality problems at microscale in urban environments, as they are capable of providing valuable information for better and more efficient urban air quality planning. The aim of this paper was to measure the CO concentration near roadways and intersections at three major roads in Kota Kinabalu city centre during morning, afternoon and evening peak hours using CAL3QHC dispersion model and also to identify CO concentration;hot-spots'.
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    Climate change simulations in terms of solar radiation and cloud fraction based on PRECIS over Malaysia region
    (UMS, 2013) Steven S.K. Kong; Justin Sentian
    This paper simulated the solar radiation and total cloud fraction for Malaysia by the end of the 21st century based on the A2 and the B2 scenarios by utilizing the latest generation of the Hadley Centre regional climate modeling system, PRECIS (Providing Regional Climates for Impact Studies).