This study investigates the recent extreme temperature trends across 19 stations in the Klang Valley, Malaysia, over the period 2006^-16. Fourteen extreme index trends were analyzed using the Mann-Kendall non-parametr...This study investigates the recent extreme temperature trends across 19 stations in the Klang Valley, Malaysia, over the period 2006^-16. Fourteen extreme index trends were analyzed using the Mann-Kendall non-parametric test, with Sen’s slope as a magnitude estimator. Generally, the annual daily mean temperature, daily mean maximum temperature, and daily mean minimum temperature in the Klang Valley increased significantly, by 0.07°C yr^-1, 0.07°C yr^-1 and 0.08°C yr^-1, respectively. For the warm temperature indices, the results indicated a significant upward trend for the annual maximum of maximum temperature, by 0.09°C yr^-1, and the annual maximum of minimum temperature, by 0.11°C yr^-1. The results for the total number of warm days and warm nights showed significant increasing trends of 5.02 d yr^-1 and 6.92 d yr^-1, respectively. For the cold temperature indices, there were upward trends for the annual minimum of maximum temperature, by 0.09°C yr^-1, and the annual minimum of minimum temperature, by 0.03°C yr^-1, concurrent with the decreases in the total number cold days (TX10P), with -3.80 d yr^-1, and cold nights (TN10P), with -4.33 d yr^-1. The 34°C and 37°C summer days results showed significant upward trends of 4.10 d yr^-1 and 0.25 d yr^-1, respectively. Overall, these findings showed upward warming trends in the Klang Valley, with the minimum temperature rate increasing more than that of the maximum temperature, especially in urban areas.展开更多
Haze episodes have become a major concern in Malaysia over the past few decades and have an increasingly important impact on the country each and every year. During haze episodes from biomass burning in Southeast Asia...Haze episodes have become a major concern in Malaysia over the past few decades and have an increasingly important impact on the country each and every year. During haze episodes from biomass burning in Southeast Asia, particularly from Sumatra, Indonesia, particulate matter PM2.5 is found to be one of the dangerous sources of airborne pollution and is known to seriously affect human health. This study determines the composition of carbohydrates （as levoglucosan）, surfactants, major elements, and anions in PM2.5 during a 2013 haze episode. PM2.5 samples were collected from Universiti Kebangsaan Malaysia, Bangi, using a high volume sampler during a seven-day monitoring campaign during the peak of that year＇s haze episode. PM2.5 concentrations ranged between 14.52 and 160.93 μg/m3, exceeding the 2005 WHO air quality guidelines for PM2.5 （25 μg/m3 for 24-h mean）. The patterns for levoglucosan, surfactants, major elements, and anionic compositions were proportional to the PM2.5 concentrations. Changes in PM2.5 observed on days 3 and 4 were influenced by a combination of meteorological factors, which substantiate the theory that such factors play a pivotal role in haze episodes.展开更多
基金supported by Newton-Ungku Omar Grant (XX-2017-002)
文摘This study investigates the recent extreme temperature trends across 19 stations in the Klang Valley, Malaysia, over the period 2006^-16. Fourteen extreme index trends were analyzed using the Mann-Kendall non-parametric test, with Sen’s slope as a magnitude estimator. Generally, the annual daily mean temperature, daily mean maximum temperature, and daily mean minimum temperature in the Klang Valley increased significantly, by 0.07°C yr^-1, 0.07°C yr^-1 and 0.08°C yr^-1, respectively. For the warm temperature indices, the results indicated a significant upward trend for the annual maximum of maximum temperature, by 0.09°C yr^-1, and the annual maximum of minimum temperature, by 0.11°C yr^-1. The results for the total number of warm days and warm nights showed significant increasing trends of 5.02 d yr^-1 and 6.92 d yr^-1, respectively. For the cold temperature indices, there were upward trends for the annual minimum of maximum temperature, by 0.09°C yr^-1, and the annual minimum of minimum temperature, by 0.03°C yr^-1, concurrent with the decreases in the total number cold days (TX10P), with -3.80 d yr^-1, and cold nights (TN10P), with -4.33 d yr^-1. The 34°C and 37°C summer days results showed significant upward trends of 4.10 d yr^-1 and 0.25 d yr^-1, respectively. Overall, these findings showed upward warming trends in the Klang Valley, with the minimum temperature rate increasing more than that of the maximum temperature, especially in urban areas.
文摘Haze episodes have become a major concern in Malaysia over the past few decades and have an increasingly important impact on the country each and every year. During haze episodes from biomass burning in Southeast Asia, particularly from Sumatra, Indonesia, particulate matter PM2.5 is found to be one of the dangerous sources of airborne pollution and is known to seriously affect human health. This study determines the composition of carbohydrates （as levoglucosan）, surfactants, major elements, and anions in PM2.5 during a 2013 haze episode. PM2.5 samples were collected from Universiti Kebangsaan Malaysia, Bangi, using a high volume sampler during a seven-day monitoring campaign during the peak of that year＇s haze episode. PM2.5 concentrations ranged between 14.52 and 160.93 μg/m3, exceeding the 2005 WHO air quality guidelines for PM2.5 （25 μg/m3 for 24-h mean）. The patterns for levoglucosan, surfactants, major elements, and anionic compositions were proportional to the PM2.5 concentrations. Changes in PM2.5 observed on days 3 and 4 were influenced by a combination of meteorological factors, which substantiate the theory that such factors play a pivotal role in haze episodes.
