Noorlin Mohamad

Source apportionment and health risk assessment of PM10 in a naturally ventilated school in a tropical environment.

This study aimed to investigate the chemical composition and potential sources of PM10 as well as assess the potential health hazards it posed to school children. PM10 samples were taken from classrooms at a school in Kuala Lumpurs city centre (S1) and one in the suburban city of Putrajaya (S2) over a period of eight hours using a low volume sampler (LVS). The composition of the major ions and trace metals in PM10 were then analysed using ion chromatography (IC) and inductively coupled plasma-mass spectrometry (ICP-MS), respectively. The results showed that the average PM10 concentration inside the classroom at the city centre school (82µg/m(3)) was higher than that from the suburban school (77µg/m(3)). Principal component analysis-absolute principal component scores (PCA-APCS) revealed that road dust was the major source of indoor PM10 at both school in the city centre (36%) and the suburban location (55%). The total hazard quotient (HQ) calculated, based on the formula suggested by the United States Environmental Protection Agency (USEPA), was found to be slightly higher than the acceptable level of 1, indicating that inhalation exposure to particle-bound non-carcinogenic metals of PM10, particularly Cr exposure by children and adults occupying the school environment, was far from negligible.

Characterization of rainwater chemical composition after a Southeast Asia haze event: insight of transboundary pollutant transport during the northeast monsoon

Open biomass burning in Peninsula Malaysia, Sumatra, and parts of the Indochinese region is a major source of transboundary haze pollution in the Southeast Asia. To study the influence of haze on rainwater chemistry, a short-term investigation was carried out during the occurrence of a severe haze episode from March to April 2014. Rainwater samples were collected after a prolonged drought and analyzed for heavy metals and major ion concentrations using inductively coupled plasma mass spectroscopy (ICP-MS) and ion chromatography (IC), respectively. The chemical composition and morphology of the solid particulates suspended in rainwater were examined using a scanning electron microscope coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). The dataset was further interpreted using enrichment factors (EF), statistical analysis, and a back trajectory (BT) model to find the possible sources of the particulates and pollutants. The results show a drop in rainwater pH from near neutral (pH 6.54) to acidic (<pH 4.00) during the haze to non-haze transitional period, suggesting that the deposition rate of sulfate and nitrate in the atmosphere via the precipitation process was relatively lower compared to the mineral components. Zinc, nitrate, and calcium, which were the predominant elements in the first rainwater samples. Besides, the results of the SEM-EDS indicated that the zinc was possibly originated from anthropogenic activities which are consistent with the results obtained from EF. The BT model showed that pollutants transported from the mainland of Indo-China and the marine region in the South China Sea were responsible for the high pollution event in the study area. These findings can be useful in identifying contributions of pollutants from single or multiple sources in rainwater samples during haze episodes.

Source Apportionment of Particulate Matter (PM10) and Indoor Dust in a University Building

A study on source apportionment of indoor dust and particulate matter (PM10) composition was conducted in a university building by using chemometrics. The objective of this study was to investigate the potential sources of selected heavy metals and ionic species in PM10 and indoor dust. PM10 samples were collected using a low-volume sampler (LVS) and indoor dust was collected using a soft brush. Inductively coupled plasma spectrometry (ICP-MS) was used to determine the concentration of heavy metals, while the concentration of cations and anions was determined by atomic absorption spectrometer (AAS) and ion chromatography (IC), respectively. The concentration of PM10 recorded in the building throughout the sampling period ranged from 20 ± 10 μgm−3 to 80 ± 33 μgm−3. The composition of heavy metals in PM10 and indoor dust were dominated by zinc (Zn), followed by lead (Pb), copper (Cu), and cadmium (Cd). Principle component analysis (PCA) and multiple linear regression (MLR) showed that the main sources of pollutants in PM10 came from indoor renovations (73.83%), vehicle emissions (16.38%), earth crust sources (9.68%), and other outdoor sources (0.11%). For indoor dust, the pollutant source was mainly earth crust. This study suggests that chemometrics can be used for forensic investigation to determine the possible sources of indoor contaminants within a public building.

Indoor/outdoor of PM10 relationships and its water-soluble ions composition in selected primary schools in Malaysia

Measurements of PM10 and water-soluble ions were carried out on indoor and outdoor PM10 (particles > 10 μm in aerodynamic diameter) aerosols sampled at selected primary schools of Kuala Lumpur (S1) and Putrajaya (S2), respectively. Samples were collected using a low volume sampler on Teflon filters. The water-soluble ions chloride (Cl−), nitrate (NO3−), sulfate (SO42−), calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+) and ammonium (NH4+) was analyzed using ion chromatography. The results showed that the indoor PM10 mass concentrations in S1 and S2 were 96.6 and 69.5 μg/m3, while the outdoor PM10 mass concentrations were 80.1 and 85.2 μg/m3, respectively. This indicated that NO3− were the most dominant ions, followed by SO42−, Ca2+, K+ and Na+, while Cl−, Mg2+ and Na+ were present at low concentrations. Pearsons correlation test applied to all the data showed high correlation between SO42− and NO3−, indicating a common anthropogenic origin. In addition, the correlations between Na+ and Ca2+ ...

Receptor Modeling Prediction for Potential Sources of PM10 at an Urban Location in Klang Valley, Malaysia

This study aims to investigate the characterization and source apportionment of PM10 at an urban site in Peninsular Malaysia. Principle component analysis (PCA) coupled with absolute principle component score (APCS) and multiple linear regression analysis (MLRA) were employed as a hybrid receptor model to perform the apportionment of PM10 sources. An hourly real time in situ data set of gases (e.g. CO, O3, SO2, NOx, NO, and NO2) and meteorological variables (e.g., ambient temperature, relative humidity and wind speed) measured at Petaling Jaya site of Selangor for a span of one year from January till December 2009 were used. The most sporadic variability of concentration of PM10 was noticed during south westerly and north easterly monsoon. PCA-APCS-MLRA predicted two predominant factors: (a) traffic emission and (b) meteorological factors-O3 source by which contributed 25 and 8 %, respectively, to PM10 concentration.

Chemical Composition and Sources of Indoor and Outdoor PM10 in Primary Schools

Indoor and outdoor measurements of PM10 (particles Zn > Fe > Ni > Cr > Pb > Cu > Co > Cd and Al > Zn > Fe > Ni > Cr > Cu > Pb > Co > Cd, respectively. The results of EF analysis found to be >1 for most elements studied. Results obtained by PCA-MLR indicate the dominance of earth crust sources (53 %), indoor activities (33 %) and corrosion product (14 %) in indoor PM10. Soil (42 %) was dominant in outdoor PM10 followed by vehicle exhaust (39 %), secondary aerosol (12 %) and construction activities (7 %).