Displaying publications 1 - 20 of 35 in total

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  1. Yu H, Zahidi I
    Sci Total Environ, 2023 Mar 15;864:161135.
    PMID: 36566867 DOI: 10.1016/j.scitotenv.2022.161135
    The over-exploitation of mineral resources has led to increasingly serious dust pollution in mines, resulting in a series of negative impacts on the environment, mine workers (occupational health) and nearby residents (public health). For the environment, mine dust pollution is considered a major threat on surface vegetation, landscapes, weather conditions and air quality, leading to serious environmental damage such as vegetation reduction and air pollution; for occupational health, mine dust from the mining process is also regarded as a major threat to mine workers' health, leading to occupational diseases such as pneumoconiosis and silicosis; for public health, the pollutants contained in mine dust may pollute surrounding rivers, farmlands and crops, which poses a serious risk to the domestic water and food security of nearby residents who are also susceptible to respiratory diseases from exposure to mine dust. Therefore, the second section of this paper combines literature research, statistical studies, and meta analysis to introduce the public mainly to the severity of mine dust pollution and its hazards to the environment, mine workers (occupational health), and residents (public health), as well as to present an outlook on the management of mine dust pollution. At the same time, in order to propose a method for monitoring mine dust pollution on a regional scale, based on the Dense Dark Vegetation (DDV) algorithm, the third section of this paper analysed the aerosol optical depth (AOD) change in Dexing City of China using the data of 2010, 2014, 2018 and 2021 from the NASA MCD19A2 Dataset to explore the mine dust pollution situation and the progress of pollution treatment in Dexing City from 2010 to 2021. As a discussion article, this paper aims to review the environmental and health risks caused by mine dust pollution, to remind the public to take mine dust pollution seriously, and to propose the use of remote sensing technologies to monitor mine dust pollution, providing suggestions for local governments as well as mines on mine dust monitoring measures.
    Matched MeSH terms: Dust/analysis
  2. Shahab A, Hui Z, Rad S, Xiao H, Siddique J, Huang LL, et al.
    Environ Geochem Health, 2023 Mar;45(3):585-606.
    PMID: 35347514 DOI: 10.1007/s10653-022-01255-3
    In order to expound on the present situation and potential risk of road dust heavy metals in major cities, a total of 114 literatures mainly over the past two decades, involving more than 5000 sampling sites in 61 cities of 21 countries, were screened through the collection and analysis of research papers. The concentration, sources, distribution, health risk, sample collection, and analytical methods of heavy metal research on road dust in cities around the world are summarized. The results show that Cd, Zn, and Cu in many urban road dusts in the world are higher than the grade II of the Chinese maximum allowable concentration of potentially toxic elements in the soil. Geo-accumulation index values show that Pb > Cd > Zn > Cu had the highest contamination levels. Hazard index assessment indicates Pb and Cr had the highest potential health risk, especially for children in which ingestion was found as the main exposure pathway. Moreover, through comparative analysis, it is found that some pollutants are higher in developed and industrialized cities and transport (53%) followed by industrial emissions (35%) provide the major contributions to the sources of heavy metals.
    Matched MeSH terms: Dust/analysis
  3. Omar M, Sulaiman I, Hassan A, Wood AK
    Radiat Prot Dosimetry, 2007;124(4):400-6.
    PMID: 17510205
    Measurements of external radiation level, radon/thoron daughters concentrations in air and uranium/thorium concentrations in airborne mineral dust at 16 amang plants in Malaysia were carried out for three consecutive months to assess radiation dose to workers. Estimated occupational dose was within the range of 1.7-10.9 mSv y(-1). The mean total dose at the amang plants was 4.1 mSv y(-1). Overall, it was found that the major dose contribution of 80% came from external radiation. Radon/thoron daughters and airborne mineral dust contributed to only 11 and 9% of the total dose, respectively.
    Matched MeSH terms: Dust/analysis
  4. Mariana A, Ho TM, Sofian-Azirun M, Wong AL
    PMID: 11414418
    Allergy to house dust mites (HDM) is an important cause of asthma and rhinitis in Malaysia. This study was carried out to evaluate the dust mite fauna in the Klang Valley. Dust samples were collected from 20 houses from March 1994 to February 1995. Thirty-three dust samples from mattresses were examined monthly for the occurrence of HDM. A total of 22 species in 9 families of HDM was identified. The most common and densely populated species was Blomia tropicalis with an average density of 8,934 mites/g of dust. Dermatophagoides pteronyssinus was the next in abundance, followed by Malayoglyphus intermedius. All houses surveyed were found to be infested with HDM and every house had at least 6 species of HDM. B. tropicalis and D. pteronyssinus were found in all mattresses. HDM in the Klang Valley were found to be highly prevalent and present in high densities. In this study, counts of D. pteronyssinus was found to exceed the proposed exposure threshold of 500 mites/g dust, for triggering acute asthma. Although counts of B. tropicalis exceeded D. pteronyssinus, no conclusion could be made because there is currently no exposure threshold for triggering acute asthma, for this species. Monthly distribution of B. tropicalis and D. pteronyssinus showed 2 peaks and 4 peaks, respectively. The major peak for D. pteronysinus was in January 1995 whereas for B. tropicalis, the major peak was more variable and occurred between November 1994 to January 1995. Both the species showed minor peak in April 1994.
    Matched MeSH terms: Dust/analysis*
  5. Norbäck D, Hashim JH, Hashim Z, Sooria V, Ismail SA, Wieslander G
    Int J Hyg Environ Health, 2017 06;220(4):697-703.
    PMID: 28254266 DOI: 10.1016/j.ijheh.2017.01.016
    BACKGROUND: There are few studies on ocular effects of indoor mould exposure in schools, especially in the tropics OBJECTIVE: To study associations between eye symptoms and tear film break up time (BUT) in students and demographic data and fungal DNA in schools.

    METHODS: A school environment study was performed among randomly selected students in eight randomly selected secondary schools in Penang, Malaysia. Information on eye symptoms and demographic data was collected by a standardised questionnaire. BUT was measured by two methods, self-reported BUT (SBUT) and by the non-invasive Tearscope (NIBUT). Dust was collected by vacuuming in 32 classrooms and analysed for five fungal DNA sequences. Geometric mean (GM) for total fungal DNA was 7.31*104 target copies per gram dust and for Aspergillus/Penicillium DNA 3.34*104 target copies per gram dust. Linear mixed models and 3-level multiple logistic regression were applied adjusting for demographic factors.

    RESULTS: A total of 368 students (58%) participated and 17.4% reported weekly eye symptoms the last 3 months. The median SBUT and TBUT were 15 and 12s, respectively. Students wearing glasses (OR 2.41, p=0.01) and with a history of atopy (OR=2.67; p=0.008) had more eye symptoms. Girls had less eye symptoms than boys (OR=0.34; p=0.006) Indoor carbon dioxide in the classrooms was low (range 380-720ppm), temperature was 25-30°C and relative air humidity 70-88%. Total fungal DNA in vacuumed dust was associated with shorter SBUT (4s shorter per 105 target copies per gram dust; p=0.04) and NIBUT (4s shorter per 105 target copies per gram dust; p<0.001). Aspergillus/Penicillium DNA was associated with shorter NIBUT (5s shorter per 105 target copies per gram dust; p=0.01).

    CONCLUSION: Fungal contamination in schools in a tropical country can be a risk factor for impaired tear film stability among students.

    Matched MeSH terms: Dust/analysis*
  6. Lee YZ, Kow ASF, Jacquet A, Lee MT, Tham CL
    Exp Appl Acarol, 2023 Dec;91(4):509-539.
    PMID: 37995026 DOI: 10.1007/s10493-023-00857-5
    The prevalence of house dust mite (HDM) allergy, especially in Asian countries with rapid urbanization, has been increasing. House dust mites thrive in places with relatively high humidity. With the combination of climate change, naturally high humidity, and urbanization, tropical countries like Malaysia are becoming a hotspot for HDM allergy fast. With a previously reported sensitization rate of between 60 and 80%, it is a worrying trend for Malaysia. However, due to incomplete and out-of-date data, as seen by the limited study coverage in the past, these numbers do not paint a complete picture of the true HDM allergy scene in Malaysia. This review briefly discusses the HDM fauna, the HDM sensitization rate, the common diagnosis and therapeutic tools for HDM allergy in Malaysia, and makes suggestions for possible improvements in the future. This review also highlights the need of more comprehensive population-based prevalence studies to be done in Malaysia, encompassing the three main HDMs-Dermatophagoides pteronyssinus, Dermatophagoides farinae, and Blomia tropicalis-as the lack of up-to-date studies failed to give a clearer picture on the current scenario of HDM allergy in Malaysia. Future studies will be beneficial to the nation in preparing a better blueprint for the management and treatment of HDM allergy.
    Matched MeSH terms: Dust/analysis
  7. Wahid NB, Latif MT, Suratman S
    Chemosphere, 2013 Jun;91(11):1508-16.
    PMID: 23336924 DOI: 10.1016/j.chemosphere.2012.12.029
    This study was conducted to determine the composition and source apportionment of surfactant in atmospheric aerosols around urban and semi-urban areas in Malaysia based on ionic compositions. Colorimetric analysis was undertaken to determine the concentrations of anionic surfactants as Methylene Blue Active Substances (MBAS) and cationic surfactants as Disulphine Blue Active Substances (DBAS) using a UV spectrophotometer. Ionic compositions were determined using ion chromatography for cations (Na(+), NH4(+), K(+), Mg(2+), Ca(2+)) and anions (F(-), Cl(-), NO3(-), SO4(2-)). Principle component analysis (PCA) combined with multiple linear regression (MLR) were used to identify the source apportionment of MBAS and DBAS. Results indicated that the concentrations of surfactants at both sampling sites were dominated by MBAS rather than DBAS especially in fine mode aerosols during the southwest monsoon. Three main sources of surfactants were identified from PCA-MLR analysis for MBAS in fine mode samples particularly in Kuala Lumpur, dominated by motor vehicles, followed by soil/road dust and sea spray. Besides, for MBAS in coarse mode, biomass burning/sea spray were the dominant source followed by motor vehicles/road dust and building material.
    Matched MeSH terms: Dust/analysis
  8. Shaharom S, Latif MT, Khan MF, Yusof SNM, Sulong NA, Wahid NBA, et al.
    Environ Sci Pollut Res Int, 2018 Sep;25(27):27074-27089.
    PMID: 30019134 DOI: 10.1007/s11356-018-2745-0
    This study aims to determine the concentrations of surfactants in the surface microlayer (SML), subsurface water (SSW) and fine mode aerosol (diameter size dust (23%) and sulphate/fresh sea salt (8%). During the southwest monsoon, the three main sources of atmospheric aerosol were biomass burning (71%), secondary inorganic aerosol (23%) and sea spray (6%). This study suggests anthropogenic sources are main contributors to the concentrations of surfactants in SML, SSW and fine aerosols.
    Matched MeSH terms: Dust/analysis
  9. Fu X, Yuan Q, Zhu X, Li Y, Meng Y, Hashim JH, et al.
    Environ Sci Process Impacts, 2021 Aug 01;23(8):1171-1181.
    PMID: 34278392 DOI: 10.1039/d1em00115a
    Pathogens are commonly present in the human respiratory tract, but symptoms are varied among individuals. The interactions between pathogens, commensal microorganisms and host immune systems are important in shaping the susceptibility, development and severity of respiratory diseases. Compared to the extensive studies on the human microbiota, few studies reported the association between indoor microbiome exposure and respiratory infections. In this study, 308 students from 21 classrooms were randomly selected to survey the occurrence of respiratory infections in junior high schools of Johor Bahru, Malaysia. Vacuum dust was collected from the floor, chairs and desks of these classrooms, and high-throughput amplicon sequencing (16S rRNA and ITS) and quantitative PCR were conducted to characterize the absolute concentration of the indoor microorganisms. Fifteen bacterial genera in the classes Actinobacteria, Alphaproteobacteria, and Cyanobacteria were protectively associated with respiratory infections (p < 0.01), and these bacteria were mainly derived from the outdoor environment. Previous studies also reported that outdoor environmental bacteria were protectively associated with chronic respiratory diseases, such as asthma, but the genera identified were different between acute and chronic respiratory diseases. Four fungal genera from Ascomycota, including Devriesia, Endocarpon, Sarcinomyces and an unclassified genus from Herpotrichillaceae, were protectively associated with respiratory infections (p < 0.01). House dust mite (HDM) allergens and outdoor NO2 concentration were associated with respiratory infections and infection-related microorganisms. A causal mediation analysis revealed that the health effects of HDM and NO2 were partially or fully mediated by the indoor microorganisms. This is the first study to explore the association between environmental characteristics, microbiome exposure and respiratory infections in a public indoor environment, expanding our understanding of the complex interactions among these factors.
    Matched MeSH terms: Dust/analysis
  10. Fu X, Norbäck D, Yuan Q, Li Y, Zhu X, Hashim JH, et al.
    Environ Int, 2020 05;138:105664.
    PMID: 32200316 DOI: 10.1016/j.envint.2020.105664
    Indoor microbial diversity and composition are suggested to affect the prevalence and severity of asthma by previous home microbiome studies, but no microbiome-health association study has been conducted in a school environment, especially in tropical countries. In this study, we collected floor dust and environmental characteristics from 21 classrooms, and health data related to asthma symptoms from 309 students, in junior high schools in Johor Bahru, Malaysia. The bacterial and fungal composition was characterized by sequencing 16s rRNA gene and internal transcribed spacer (ITS) region, and the absolute microbial concentration was quantified by qPCR. In total, 326 bacterial and 255 fungal genera were characterized. Five bacterial (Sphingobium, Rhodomicrobium, Shimwellia, Solirubrobacter, Pleurocapsa) and two fungal (Torulaspora and Leptosphaeriaceae) taxa were protective for asthma severity. Two bacterial taxa, Izhakiella and Robinsoniella, were positively associated with asthma severity. Several protective bacterial taxa including Rhodomicrobium, Shimwellia and Sphingobium have been reported as protective microbes in previous studies, whereas other taxa were first time reported. Environmental characteristics, such as age of building, size of textile curtain per room volume, occurrence of cockroaches, concentration of house dust mite allergens transferred from homes by the occupants, were involved in shaping the overall microbial community but not asthma-associated taxa; whereas visible dampness and mold, which did not change the overall microbial community for floor dust, was negatively associated with the concentration of protective bacteria Rhodomicrobium (β = -2.86, p = 0.021) of asthma. The result indicates complex interactions between microbes, environmental characteristics and asthma symptoms. Overall, this is the first indoor microbiome study to characterize the asthma-associated microbes and their environmental determinant in the tropical area, promoting the understanding of microbial exposure and respiratory health in this region.
    Matched MeSH terms: Dust/analysis
  11. Othman N, Ismail Z, Selamat MI, Sheikh Abdul Kadir SH, Shibraumalisi NA
    Int J Environ Res Public Health, 2022 Oct 26;19(21).
    PMID: 36360801 DOI: 10.3390/ijerph192113923
    Polychlorinated biphenyls (PCBs) were widely used in industrial and commercial applications, until they were banned in the late 1970s as a result of their significant environmental pollution. PCBs in the environment gained scientific interest because of their persistence and the potential threats they pose to humans. Traditionally, human exposure to PCBs was linked to dietary ingestion. Inhalational exposure to these contaminants is often overlooked. This review discusses the occurrence and distribution of PCBs in environmental matrices and their associated health impacts. Severe PCB contamination levels have been reported in e-waste recycling areas. The occurrence of high PCB levels, notably in urban and industrial areas, might result from extensive PCB use and intensive human activity. Furthermore, PCB contamination in the indoor environment is ten-fold higher than outdoors, which may present expose risk for humans through the inhalation of contaminated air or through the ingestion of dust. In such settings, the inhalation route may contribute significantly to PCB exposure. The data on human health effects due to PCB inhalation are scarce. More epidemiological studies should be performed to investigate the inhalation dose and response mechanism and to evaluate the health risks. Further studies should also evaluate the health impact of prolonged low-concentration PCB exposure.
    Matched MeSH terms: Dust/analysis
  12. Jathar LD, Ganesan S, Awasarmol U, Nikam K, Shahapurkar K, Soudagar MEM, et al.
    Environ Pollut, 2023 Jun 01;326:121474.
    PMID: 36965686 DOI: 10.1016/j.envpol.2023.121474
    Recently, solar photovoltaic (PV) technology has shown tremendous growth among all renewable energy sectors. The attractiveness of a PV system depends deeply of the module and it is primarily determined by its performance. The quantity of electricity and power generated by a PV cell is contingent upon a number of parameters that can be intrinsic to the PV system itself, external or environmental. Thus, to improve the PV panel performance and lifetime, it is crucial to recognize the main parameters that directly influence the module during its operational lifetime. Among these parameters there are numerous factors that positively impact a PV system including the temperature of the solar panel, humidity, wind speed, amount of light, altitude and barometric pressure. On the other hand, the module can be exposed to simultaneous environmental stresses such as dust accumulation, shading and pollution factors. All these factors can gradually decrease the performance of the PV panel. This review not only provides the factors impacting PV panel's performance but also discusses the degradation and failure parameters that can usually affect the PV technology. The major points include: 1) Total quantity of energy extracted from a photovoltaic module is impacted on a daily, quarterly, seasonal, and yearly scale by the amount of dust formed on the surface of the module. 2) Climatic conditions as high temperatures and relative humidity affect the operation of solar cells by more than 70% and lead to a considerable decrease in solar cells efficiency. 3) The PV module current can be affected by soft shading while the voltage does not vary. In the case of hard shadowing, the performance of the photovoltaic module is determined by whether some or all of the cells of the module are shaded. 4) Compared to more traditional forms of energy production, PV systems offer a significant number of advantages to the environment. Nevertheless, these systems can procure greenhouse gas emissions, especially during the production stages. In conclusion, this study underlines the importance of considering multiple parameters while evaluating the performance of photovoltaic modules. Environmental factors can have a major impact on the performance of a PV system. It is critical to consider these factors, as well as intrinsic and other intermediate factors, to optimize the performance of solar energy systems. In addition, continuous monitoring and maintenance of PV systems is essential to ensure maximum efficiency and performance.
    Matched MeSH terms: Dust/analysis
  13. Cai GH, Hashim JH, Hashim Z, Ali F, Bloom E, Larsson L, et al.
    Pediatr Allergy Immunol, 2011 May;22(3):290-7.
    PMID: 21457336 DOI: 10.1111/j.1399-3038.2010.01127.x
    While there is a large variation of prevalence of asthma symptoms worldwide, what we do know is that it is on the rise in developing countries. However, there are few studies on allergens, moulds and mycotoxin exposure in schools in tropical countries. The aims were to measure selected fungal DNA, furry pet allergens and mycotoxins in dust samples from schools in Malaysia and to study associations with pupils' respiratory health effects. Eight secondary schools and 32 classrooms in Johor Bahru, Malaysia were randomly selected. A questionnaire with standardized questions was used for health assessment in 15 randomly selected pupils from each class. The school buildings were inspected and both indoor and outdoor climate were measured. Dust samples were collected by cotton swabs and Petri dishes for fungal DNA, mycotoxins and allergens analysis. The participation rate was 96% (462/480 invited pupils), with a mean age of 14 yr (range 14-16). The pupils mostly reported daytime breathlessness (41%), parental asthma or allergy (22%), pollen or pet allergy (21%) and doctor-diagnosed asthma (13%) but rarely reported night-time breathlessness (7%), asthma in the last 12 months (3%), medication for asthma (4%) or smoking (5%). The inspection showed that no school had any mechanical ventilation system, but all classrooms had openable windows that were kept open during lectures. The mean building age was 16 yr (range 3-40) and the mean indoor and outdoor CO(2) levels were 492 ppm and 408 ppm, respectively. The mean values of indoor and outdoor temperature and relative humidity were the same, 29°C and 70% respectively. In cotton swab dust samples, the Geometric Mean (GM) value for total fungal DNA and Aspergillus/Penicillium (Asp/Pen) DNA in swab samples (Cell Equivalents (CE)/m(2)) was 5.7*10(8) and 0.5*10(8), respectively. The arithmetic mean (CE/m(2)) for Aspergillus versicolor DNA was 8780, Stachybotrys chartarum DNA was 26 and Streptomyces DNA was 893. The arithmetic means (pg/m(2)) for the mycotoxins sterigmatocystin and verrucarol were 2547 and 17, respectively. In Petri dish dust samples, the GM value for total fungal DNA and Asp/Pen DNA (CE/m(2) per day) was 9.2*10(6) and 1.6*10(6), respectively. The arithmetic mean (CE/m(2) per day) for A. versicolor DNA was 1478, S. chartarum DNA was 105 and Streptomyces DNA was 1271, respectively. The GM value for cat (Fel d1) allergen was 5.9 ng/m(2) per day. There were positive associations between A. versicolor DNA, wheeze and daytime breathlessness and between Streptomyces DNA and doctor-diagnosed asthma. However, the associations were inverse between S. chartarum DNA and daytime breathlessness and between verrucarol and daytime breathlessness. In conclusion, fungal DNA and cat allergen contamination were common in schools from Malaysia and there was a high prevalence of respiratory symptoms among pupils. Moreover, there were associations between levels of some fungal DNA and reported respiratory health in the pupils.
    Matched MeSH terms: Dust/analysis*
  14. Lim FL, Hashim Z, Than LTL, Md Said S, Hashim JH, Norbäck D
    Int J Tuberc Lung Dis, 2019 11 01;23(11):1171-1177.
    PMID: 31718753 DOI: 10.5588/ijtld.18.0668
    OBJECTIVE: To examine the associations between endotoxin and (1,3)-β-glucan concentrations in office dust and respiratory symptoms and airway inflammation among 695 office workers in Malaysia.METHODS: Health data were collected using a questionnaire, sensitisation testing and measurement of fractional exhaled nitric oxide (FeNO). Indoor temperature, relative air humidity (RH) and carbon dioxide (CO₂) were measured in the offices and settled dust was vacuumed and analysed for endotoxin and (1,3)-β-glucan concentrations. Associations were analysed by two level multiple logistic regression.RESULTS: Overall, 9.6% of the workers had doctor-diagnosed asthma, 15.5% had wheeze, 18.4% had daytime attacks of breathlessness and 25.8% had elevated FeNO (≥25 ppb). The median levels in office dust were 11.3 EU/mg endotoxin and 62.9 ng/g (1,3)-β-glucan. After adjusting for personal and home environment factors, endotoxin concentration in dust was associated with wheeze (P = 0.02) and rhinoconjunctivitis (P = 0.007). The amount of surface dust (P = 0.04) and (1,3)-β-glucan concentration dust (P = 0.03) were associated with elevated FeNO.CONCLUSION: Endotoxin in office dust could be a risk factor for wheeze and rhinoconjunctivitis among office workers in mechanically ventilated offices in a tropical country. The amount of dust and (1,3)-β-glucan (a marker of indoor mould exposure) were associated with Th2 driven airway inflammation.
    Matched MeSH terms: Dust/analysis*
  15. Latif MT, Ngah SA, Dominick D, Razak IS, Guo X, Srithawirat T, et al.
    J Environ Sci (China), 2015 Jul 1;33:143-55.
    PMID: 26141887 DOI: 10.1016/j.jes.2015.02.002
    The aim of this study was to determine the source apportionment of dust fall around Lake Chini, Malaysia. Samples were collected monthly between December 2012 and March 2013 at seven sampling stations located around Lake Chini. The samples were filtered to separate the dissolved and undissolved solids. The ionic compositions (NO3-, SO4(2-), Cl- and NH4+) were determined using ion chromatography (IC) while major elements (K, Na, Ca and Mg) and trace metals (Zn, Fe, Al, Ni, Mn, Cr, Pb and Cd) were determined using inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the average concentration of total solids around Lake Chini was 93.49±16.16 mg/(m2·day). SO4(2-), Na and Zn dominated the dissolved portion of the dust fall. The enrichment factors (EF) revealed that the source of the trace metals and major elements in the rain water was anthropogenic, except for Fe. Hierarchical agglomerative cluster analysis (HACA) classified the seven monitoring stations and 16 variables into five groups and three groups respectively. A coupled receptor model, principal component analysis multiple linear regression (PCA-MLR), revealed that the sources of dust fall in Lake Chini were dominated by agricultural and biomass burning (42%), followed by the earth's crust (28%), sea spray (16%) and a mixture of soil dust and vehicle emissions (14%).
    Matched MeSH terms: Dust/analysis*
  16. Razak IS, Latif MT, Jaafar SA, Khan MF, Mushrifah I
    Environ Sci Pollut Res Int, 2015 Apr;22(8):6024-33.
    PMID: 25382497 DOI: 10.1007/s11356-014-3781-z
    This study was conducted to determine the composition of surfactants in atmospheric aerosols and rainwater in the vicinity of Lake Chini, Malaysia. Samples of atmospheric aerosol and rainwater were collected between March and September 2011 using a high volume air sampler (HVAS) and glass bottles equipped with funnel. Colorimetric analysis was undertaken to determine the concentration of anionic surfactants as methylene blue active substances (MBAS) and cationic surfactants as disulphine blue active substances (DBAS). The water-soluble ionic compositions were determined using inductively coupled plasma mass spectrometry for cations (Na, K, Mg and Ca) and ion chromatography equipped with a conductivity detector for anions (F(-), Cl(-), NO3(-), and SO4(2-)) and the Nessler Method was used to obtain the NH4(+) concentrations. The source apportionment of MBAS and DBAS in atmospheric aerosols was identified using a combination of principal component analysis (PCA) and multiple linear regression (MLR). The results revealed that the concentrations of surfactants in atmospheric aerosols and rainwater were dominated by anionic surfactants as MBAS. The concentration of surfactants as MBAS and DBAS was dominated in fine mode compared to coarse mode aerosols. Using PCA/MLR analysis, two major sources of atmospheric surfactants to Lake Chini were identified as soil dust (75 to 93%) and biomass burning (2 to 22%).
    Matched MeSH terms: Dust/analysis
  17. Othman M, Latif MT, Mohamed AF
    Ecotoxicol Environ Saf, 2018 Feb;148:293-302.
    PMID: 29080527 DOI: 10.1016/j.ecoenv.2017.10.034
    This study intends to determine the health impacts from two office life cycles (St.1 and St.2) using life cycle assessment (LCA) and health risk assessment of indoor metals in coarse particulates (particulate matter with diameters of less than 10µm). The first building (St.1) is located in the city centre and the second building (St.2) is located within a new development 7km away from the city centre. All life cycle stages are considered and was analysed using SimaPro software. The trace metal concentrations were determined by inductively couple plasma-mass spectrometry (ICP-MS). Particle deposition in the human lung was estimated using the multiple-path particle dosimetry model (MPPD). The results showed that the total human health impact for St.1 (0.027 DALY m-2) was higher than St.2 (0.005 DALY m-2) for a 50-year lifespan, with the highest contribution from the operational phase. The potential health risk to indoor workers was quantified as a hazard quotient (HQ) for non-carcinogenic elements, where the total values for ingestion contact were 4.38E-08 (St.1) and 2.59E-08 (St.2) while for dermal contact the values were 5.12E-09 (St.1) and 2.58E-09 (St.2). For the carcinogenic risk, the values for dermal and ingestion routes for both St.1 and St.2 were lower than the acceptable limit which indicated no carcinogenic risk. Particle deposition for coarse particles in indoor workers was concentrated in the head, followed by the pulmonary region and tracheobronchial tract deposition. The results from this study showed that human health can be significantly affected by all the processes in office building life cycle, thus the minimisation of energy consumption and pollutant exposures are crucially required.
    Matched MeSH terms: Dust/analysis
  18. Othman M, Latif MT, Matsumi Y
    Ecotoxicol Environ Saf, 2019 Apr 15;170:739-749.
    PMID: 30583285 DOI: 10.1016/j.ecoenv.2018.12.042
    It is important to assess indoor air quality in school classrooms where the air quality may significantly influence school children's health and performance. This study aims to determine the concentrations of PM2.5 and dust chemical compositions in indoor and outdoor school classroom located in Kuala Lumpur City Centre. The PM2.5 concentration was measured from 19th September 2017-16th February 2018 using an optical PM2.5 sensor. Indoor and outdoor dust was also collected from the school classrooms and ion and trace metal concentrations were analysed using ion chromatography (IC) and inductively couple plasma-mass spectrometry (ICP-MS) respectively. This study showed that the average indoor and outdoor 24 h PM2.5 was 11.2 ± 0.45 µg m-3 and 11.4 ± 0.44 µg m-3 respectively. The 8 h PM2.5 concentration ranged between 3.2 and 28 µg m-3 for indoor and 3.2 and 19 µg m-3 for outdoor classrooms. The highest ion concentration in indoor dust was Ca2+ with an average concentration of 38.5 ± 35.0 µg g-1 while for outdoor dust SO42- recorded the highest ion concentration with an average concentration of 30.6 ± 9.37 µg g-1. Dominant trace metals in both indoor and outdoor dust were Al, Fe and Zn. Principle component analysis-multiple linear regression (PCA-MLR) demonstrated that the major source of indoor dust was road dust (69%), while soil dominated the outdoor dust (74%). Health risk assessment showed that the hazard quotient (HQ) value for non-carcinogenic trace metals was dust through dermal and inhalation pathways, but not the ingestion pathway. This study suggests indoor contributions of PM2.5 concentrations are due to the activities of the school children while the compositions of indoor and outdoor dust are greatly influenced by the soil/earth source plus industrial and traffic contribution.
    Matched MeSH terms: Dust/analysis*
  19. Ee-Ling O, Mustaffa NI, Amil N, Khan MF, Latif MT
    Bull Environ Contam Toxicol, 2015 Apr;94(4):537-42.
    PMID: 25652682 DOI: 10.1007/s00128-015-1477-9
    This study determined the source contribution of PM2.5 (particulate matter <2.5 μm) in air at three locations on the Malaysian Peninsula. PM2.5 samples were collected using a high volume sampler equipped with quartz filters. Ion chromatography was used to determine the ionic composition of the samples and inductively coupled plasma mass spectrometry was used to determine the concentrations of heavy metals. Principal component analysis with multilinear regressions were used to identify the possible sources of PM2.5. The range of PM2.5 was between 10 ± 3 and 30 ± 7 µg m(-3). Sulfate (SO4 (2-)) was the major ionic compound detected and zinc was found to dominate the heavy metals. Source apportionment analysis revealed that motor vehicle and soil dust dominated the composition of PM2.5 in the urban area. Domestic waste combustion dominated in the suburban area, while biomass burning dominated in the rural area.
    Matched MeSH terms: Dust/analysis
  20. Singh N, Banerjee T, Murari V, Deboudt K, Khan MF, Singh RS, et al.
    Chemosphere, 2021 Jan;263:128030.
    PMID: 33297051 DOI: 10.1016/j.chemosphere.2020.128030
    Size-segregated airborne fine (PM2.1) and coarse (PM>2.1) particulates were measured in an urban environment over central Indo-Gangetic plain in between 2015 and 2018 to get insights into its nature, chemistry and sources. Mean (±1σ) concentration of PM2.1 was 98 (±76) μgm-3 with a seasonal high during winter (DJF, 162 ± 71 μgm-3) compared to pre-monsoon specific high in PM>2.1 (MAMJ, 177 ± 84 μgm-3) with an annual mean of 170 (±69) μgm-3. PM2.1 was secondary in nature with abundant secondary inorganic aerosols (20% of particulate mass) and water-soluble organic carbon (19%) against metal enriched (25%) PM>2.1, having robust signature of resuspensions from Earth's crust and road dust. Ammonium-based neutralization of particulate acidity was essentially in PM2.1 with an indication of predominant H2SO4 neutralization in bisulfate form compared to Ca2+ and Mg2+-based neutralization in PM>2.1. Molecular distribution of n-alkanes homologues (C17-C35) showed Cmax at C23 (PM2.1) and C18 (PM>2.1) with weak dominance of odd-numbered n-alkanes. Carbon preference index of n-alkanes was close to unity (PM2.1: 1.4 ± 0.3; PM>2.1: 1.3 ± 0.4). Fatty acids (C12-C26) were characterized with predominance of even carbon with Cmax at n-hexadecanoic acid (C16:0). Low to high molecular weight fatty acid ratio ranged from 2.0 (PM>2.1) to 5.6 (PM2.1) with vital signature of anthropogenic emissions. Levoglucosan was abundant in PM2.1 (758 ± 481 ngm-3) with a high ratio (11.6) against galactosan, emphasizing robust contribution from burning of hardwood and agricultural residues. Receptor model resolves secondary aerosols and biomass burning emissions (45%) as the most influential sources of PM2.1 whereas, crustal (29%) and secondary aerosols (29%) were found responsible for PM>2.1; with significant variations among the seasons.
    Matched MeSH terms: Dust/analysis
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