Browsing by Author "J Sentian"

Now showing 1 - 3 of 3
  • Thumbnail Image
    ItemEmbargo
    Assessing Short Term Air Quality Trend in Malaysia based on Air Pollution Index (API)
    (IOP Publishing, 2022) J Sentian; M S Nur Sayzni; C Payus
    Air Pollution Index (API) is used in Malaysia to determine the daily air quality status, which is calculated based on the daily concentrations of particulate matter (PM10), ground level ozone (O3), carbon monoxide (CO), sulphur dioxide (SO2) and nitrogen dioxide (NO2). This study presents short-term air quality trends based on API from the 52 air quality monitoring stations nationwide between 2010 and 2016. The air quality data and meteorological conditions were obtained from the Department of Environment and used for the API calculation. The API value is classified into six categories, namely: Good (0-50), Moderate (51-100), Unhealthy (101-200), Very Unhealthy (201-300), Hazardous (301-500), and Emergency (above 500). The coefficient of variation (CV) and Mann-Kendall trend test (MK) were used to assess the API variation and trend in each air quality monitoring station. Between the study periods, the API values were largely varied. Observation at 32 air quality monitoring stations have shown significant but small increasing trends, while 12 stations showed significant decreasing trends, and the remaining 8 stations showed no significant trends. The frequency of exceedance (API>50) was used to assess the percentages of unhealthy days.
  • Thumbnail Image
    ItemEmbargo
    Beach erosion: Threat and adaptation measures of communities in the Tun Mustapha Park (TMP), Sabah, Malaysia
    (IOP Publishing, 2022) E Saleh; G Jolis; N F Osman; J Sentian; J Joseph; J Jomitol; N Adin
    Beach erosion is among the main phenomena affecting small islands in the Coral Triangle region, particularly in the Tun Mustapha Park (TMP), Malaysia. This study was done to investigate the level of beach erosion and to determine the adaptation measures for the coastal communities to beach erosion.
  • Thumbnail Image
    ItemEmbargo
    Effect of Monsoonal Clustering for PM10 Concentration Prediction in Keningau, Sabah Using Principal Component Analysis
    (IOP Publishing, 2022) Muhammad Izzuddin Rumaling; F P Chee; J H W Chang; J Sentian
    Particulate matter (PM) has caught scientific attention in scientific research due to its harmful effect on human health. While prediction is essential for future development in Keningau, temporal clustering in Keningau has yet to be studied. Thus, this research aims to determine whether monsoonal clustering is required for meteorological and pollutant concentration data collected in Keningau. Missing data is first imputed using Nearest Neighbour Method (NNM). Then, wind direction and wind speed are converted into northern (Wy) and eastern (Wx) component of wind speed. Data is then temporal clustered based on monsoonal season (NEM, IM4, SWM, IM10). Both clustered and unclustered data are analysed using principal component (PC) analysis (PCA).