Investigation of variations and trends in TSP concentrations in the Klang Valley region, Malaysia

Air pollution in the atmosphere by TSP is a problem that has been growing for the last few years due to rapid industrialization, population growth and urbanization in the Klang Valley Region. Suspended particle levels are monitored in ambient air quality network of their potential impact on human health, visibility and climate. The objective of this study is to investigate variations and trends in TSP in the Klang Valley Region and to identify the main factors affecting the variation in TSP concentrations. This analysis used daily data collected from Malaysian Meteorological Services for Petaing Jaya station monitoring TSP data for the period 1977-2002. On daily average basis, annual, seasonal, monthly and weekly variations and trends in TSP concentrations are presented. Linear regressions were performed of the annual average TSP over the 1977 through 2002. The slope of the regression line in annual average decreased in TSP in order of -0.977 and statistically significant at 0.05 level. This suggests that whatever control measures have been applied are effective in reducing TSP concentrations. TSP concentrations in the Klang Valley Region showed seasonal variation, with the higher concentration during southwest monsoon season (dry season) and lower concentrations during rainy season. The causes of highest TSP concentrations during southwest monsoon season due to lack of rainfall and the stable atmospheric conditions, which reduce the ability of atmosphere to disperse the pollutants. The weekly pattern of TSP concentration exhibits a downward trend from Tuesday (maximum) to Sunday (minimum). This weekly cycle in TSP gives the indication that the main sources of the particulates in this area are from human activities rather than natural source

Evaluation of long term trends in oxide of nitrogen concentrations in the Klang Valley region, Malaysia

Anthropogenic emissions of NOx account for a large majority of all nitrogen inputs to the environment. The major sources of man-made NOx emissions are high-temperature combustion processes such as those that occur in automobile and power plants. NOx contribute to a wide range of environmental effects directly and when combined with other precursors in acid rain and ozone. NOx react in the air to form ground-level ozone and fine particle pollution, which are associated with adverse health effects. Principally, and for a long time, transport vehicles and industrial emissions are the major sources of the pollutants emitted in the Klang Valley atmosphere. Following the increase of urbanization and industrialization, the amount of traffic has increased in the Klang Valley. Traffic is considered as the major source of NOx in the Klang Valley. Exhaust emissions from the petrol-powered motor vehicles include carbon monoxide, nitrogen oxide, hydrocarbons and particulate matter. A time series analysis of NOx monitoring data from six locations in the Klang Valley Region from 1997 to 2002 is presented. The aim of this study is to evaluate the variations and trends in NOx in the Klang Valley Region for the period 1997-2002. On an hourly and daily average basis, annual, seasonal, monthly and diurnal variations and trends in NOx concentrations are presented. The overall average daily concentration of NOx ranged from 0.03 ppm to 0.18 ppm, with maximums of about 0.32 ppm in Kuala Lumpur, with 98th percentiles in the range 0.17-0.28 ppm. It is of particular interest that all stations in 1997 showed high NOx concentrations due to haze episode. The highest level of NOx recorded in 1997 was 0.3 ppm in Kuala Lumpur. Variations in NOx were dominated by one daily peak at the morning rush hours and secondary peak in late evening. This suggests that the level of NOx during peak hour is higher and it can be attributed to the increase in traffic volume. In the Klang Valley Region, tremendous growth of motor vehicles has resulted in increasing CO and NOx emissions. Therefore, the role of source controls over emissions is stressed as a key management tool especially in relation to road transportatio

Short-term trends in suspended particulate matter (SPM) concentrations in Kuala Lumpur, Malaysia, from 1992-1995

The purpose of this study is to show the significant variations including annual, seasonal, monthly and day-to-day patterns of SPM in Kuala Lumpur for the period 1992 to 1995 in order to understand the short-term trends. The study has shown that the SPM in Kuala Lumpur was significantly high with the average value ranging from 54 to 85µg m-3, and a maximum of 300 µg m-3 was recorded. The monthly mean concentrations coincide well with seasonal cycle with higher values occurring during the month of dry seasons and lower concentrations during rainy seasons. The seasonal mean SPM concentrations showed the maximum occurring during southwest monsoon and inter-monsoon (Oct.-Nov.) with approximately 69 µg m-3 whereas the minimum during northeast monsoon 49 µg m-3 . The maximum daily average in 1993 (281 µg m-3) was 187% of Malaysia standard (150 µg m-3 for 24-hour mean) and 374% of WHO standard. The daily maximum concentrations for 1995 was 96µg m-3, this is significantly lower than the daily maximum for 1993. Air quality has greatly improved in 1995 in the area, for example the number of days with SPM pollution above the Malaysia standard (150 µg m-3 for 24-hour), declined from 15 days in 1993 to none in 199