Trends of PM10 and O3 in Malaysia of 2013

According to Malaysia Environmental Quality Report in 2013, Five (5) air pollutants consisting of particulate matter (PM10), ozone (O3), sulphur dioxide (SO2), nitrogen dioxide (NO2) and carbon monoxide (CO) were monitored continuously at 52 locations. The air quality trend for the period of 1999 to 2013 was computed by taking the yearly average measurement from the monitoring sites and cross-referencing with Malaysia Ambient Air Quality Guidelines as shown in Table 1.2.

Particulate Matter (PM10) In 2013, the annual average value of PM10 in the ambient air was 44 µg/m3, which is below the Malaysian Ambient Air Quality Guidelines value of 50 µg/m3. The concentrations for 2013 increased slightly by two (2) percent compared to 2012. Incidences of local peat land fires and transboundary smoke haze had contributed to the higher PM10 recorded intermittently in several areas in Johor, Melaka and Negeri Sembilan from June to September 2013. The trend of the annual average levels of PM10 concentration in the ambient air between 1999 and 2013 is in accordance with the Malaysian Ambient Air Quality Guidelines as shown in Figure 1.8. Based on land use categories, PM10 concentration was in compliance with the Malaysian Ambient Air Quality Guidelines as shown in Figure 1.8(a).

Ground Level Ozone (O3) In 2013, the annual average daily maximum one-hour ozone concentrations increased slightly by two (2) percent compared to 2012. However, the overall trend on the annual average daily maximum one-hour ozone concentrations in ambient air from 1999 to 2013 were well below the limit of 0.1 ppm as stipulated in the Malaysian Ambient Quality Guidelines and the trend are as shown in Figure 1.9. Figure 1.9(a) shows the ozone concentration for various land use categories between 1999 and 2013. Urban areas recorded higher levels of ozone due to higher traffic volume and conducive atmospheric conditions, resulting in its formation. Ozone pollution was also dominant in some rural and sub urban areas due to downwind effect transporting ozone pollution from the sources of ozone precursors namely nitrogen oxides (NOx) and volatile organic compound (VOC) emitted from motor vehicles and industries.