Gauging dust pollution in Malaysia’s Klang Valley using statistical analysis of boxp

One of the sources of urban air quality deterioration in the Klang Valley was increased emissions of suspended particulates matter sized less than 10 micrometers (PM_10) from motor vehicles. This study investigated the trend of monthly average concentrations of PM_10 at Klang, Petaling Jaya, Kajang, Shah Alam and Cheras air quality stations from year 2000 to year 2009 using the boxplot statistical analysis. It was found that the monthly average concentrations of PM_10 from 2000 to 2006 at all stations exceeded the monthly average equivalent of the Recommended Malaysian Air Quality Guidelines (RMAQG) of 103.5 μg/m^3 for a period of one month at several air quality stations. The highest monthly concentration of PM_10 was recorded at Klang (590 μg/m^3), Petaling Jaya (482 μg/m^3), Kajang (371 μg/m^3), Shah Alam (587 μg/m^3) and Cheras (465 μg/m^3) in Ogos 2005. Besides the maximum concentration, boxplot also analysed the Q2 (quartile 2) and the third quartile (Q3) scores. The Klang air quality station recorded the highest monthly values of Q3, Q2 and IQR in August 2005 at 342 μg/m^3, 75 μg/m^3 and 277 μg/m^3, respectively. This situation occurred as an impact of the major haze episode that originated from the biomass burning activities in Sumatra, Indonesia. The location of the Klang air quality station nearest to Sumatra was one of the reasons that the maximum PM_10 concentrations were recorded there.