Papers by Mohd Talib Latif
Sustainable Cities and Society, Dec 1, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Atmospheric Pollution Research, Oct 1, 2021
Abstract Good indoor air quality in school environment is crucial for teaching and learning proce... more Abstract Good indoor air quality in school environment is crucial for teaching and learning processes, as well as student development. This study aims to identify the composition of PM2.5 and the main sources of it which influence the indoor and outdoor school environment. The PM2.5 sampling was conducted using a portable low volume air sampler and took place at three different primary schools. The chemical composition of PM2.5 is comprised of water-soluble inorganic ions (WSII) and potentially toxic trace metals. WSII (Cl−, NO3−, SO42−, Na+, NH4+, K+, Mg2+, Ca2+) were analysed using ion chromatography (IC) and trace metals concentrations (Al, Fe, Zn, Cr, Cu, Mn, Pb, Ni, As, Co, Cd) using inductively coupled plasma-mass spectrometry (ICP-MS). The results showed that the highest average for PM2.5 concentrations in an indoor classroom was recorded at the school located in the industrial area (23.5 μg/m3) followed by urban (18.6 μg/m3) and suburban (9.58 μg/m3). The indoor to outdoor (I/O) ratio values for PM2.5 concentrations were slightly above one, indicating that open doors and windows highly affected indoor PM2.5 concentrations. Source apportionment analysis indicated that the sources of both indoor and outdoor PM2.5 were mixed of natural (crustal, mineral dust and sea salt) and anthropogenic (vehicle, industrial and biomass burning). The hazard quotient (HQ) value was lower than the acceptable limits. The excess lifetime cancer risk (ELCR) value for all three stations, however, was found to be slightly higher than the acceptable level (1.0E-06) for Cr and Ni.
Environmental Science and Pollution Research, May 1, 2015
Principal component analysis (PCA) and correlation have been used to study the variability of par... more Principal component analysis (PCA) and correlation have been used to study the variability of particle mass and particle number concentrations (PNC) in a tropical semi-urban environment. PNC and mass concentration (diameter in the range of 0.25->32.0 μm) have been measured from 1 February to 26 February 2013 using an in situ Grimm aerosol sampler. We found that the 24-h average total suspended particulates (TSP), particulate matter ≤10 μm (PM10), particulate matter ≤2.5 μm (PM2.5) and particulate matter ≤1 μm (PM1) were 14.37 ± 4.43, 14.11 ± 4.39, 12.53 ± 4.13 and 10.53 ± 3.98 μg m(-3), respectively. PNC in the accumulation mode (<500 nm) was the most abundant (at about 99 %). Five principal components (PCs) resulted from the PCA analysis where PC1 (43.8 % variance) predominates with PNC in the fine and sub-microme tre range. PC2, PC3, PC4 and PC5 explain 16.5, 12.4, 6.0 and 5.6 % of the variance to address the coarse, coarser, accumulation and giant fraction of PNC, respectively. Our particle distribution results show good agreement with the moderate resolution imaging spectroradiometer (MODIS) distribution.
Scientific Reports
To understand the characteristics of particulate matter (PM) in the Southeast Asia region, the sp... more To understand the characteristics of particulate matter (PM) in the Southeast Asia region, the spatial–temporal concentrations of PM10, PM2.5 and PM1 in Malaysia (Putrajaya, Bukit Fraser and Kota Samarahan) and Thailand (Chiang Mai) were determined using the AS-LUNG V.2 Outdoor sensor. The period of measurement was over a year from 2019 to 2020. The highest concentrations of all sizes of PM in Putrajaya, Bukit Fraser and Kota Samarahan were observed in September 2019 while the highest PM10, PM2.5 and PM1 concentrations in Chiang Mai were observed between March and early April 2020 with 24 h average concentrations during haze days in ranges 83.7–216 µg m−3, 78.3–209 µg m−3 and 57.2–140 µg m−3, respectively. The average PM2.5/PM10 ratio during haze days was 0.93 ± 0.05, which was higher than the average for normal days (0.89 ± 0.13) for all sites, indicating higher PM2.5 concentrations during haze days compared to normal days. An analysis of particle deposition in the human respirator...
Air Quality, Atmosphere & Health, 2021
Good indoor air quality (IAQ) is essential to ensure students' and teachers' improved performance... more Good indoor air quality (IAQ) is essential to ensure students' and teachers' improved performance and productivity. This study aimed to investigate particulate matter (PM) concentration with different sizes in a classroom during haze episode and to evaluate the health effect of air pollution during haze to the school student in Malaysia. The particulate matter concentration with aerodynamic diameter size less than 10 µm (PM 10) was collected for 8 h using a low volume air sampler (LVS) equipped with quartz filter paper. The trace metals element (Pb, Cd, Co, Ni, Cr, Mn, As and Cu) in PM 10 was analysed using inductively coupled plasma mass spectrometry (ICP-MS). Simultaneously, PM concentration in real time at differences sizes (PM 10 , PM 2.5 and PM 1) was also collected using Grimm aerosol spectrometer with 1-min interval. A questionnaire survey on school children's health condition and the lung function test using spirometry were also performed. The results show that there was no significant difference in PM 10 concentration during haze (95 ± 25 μg m −3). The dominant trace metal concentrations in PM 10 were Mn and Cr both during haze. The mean concentrations of continuous monitoring of PM 10 , PM 2.5 and PM 1 during haze event were 85 ± 14 μg m −3 , 68 ± 16 μg m −3 and 61 ± 16 μg m −3. The mean forced expiratory volume in the first second (FEV1) and the mean forced vital capacity (FVC) value during haze were 97.7% and 91.8%. The health risk assessment of school children on trace metals in PM 10 via inhalation was higher than the acceptable value with a total hazard quotient (HQ) more than 1.0 for both hazes. For carcinogenic elements, the excess lifetime cancer risk (ELCR) was higher than the acceptable limit for haze event with a value of 3.4XE-05. This study found that the impact of haze pollution on indoor PM 10 concentration was relatively low; however, there was still a high exposure of school children to the carcinogenic and non-carcinogenic elements during haze event.
Background: Biogenic Volatile Organic Compounds (BVOCs) such as isoprene (C5H8) are ozone (O3) pr... more Background: Biogenic Volatile Organic Compounds (BVOCs) such as isoprene (C5H8) are ozone (O3) precursors that can be emitted at significant concentrations from the oil palm tree (Elaeis guineensis). Reactions involving BVOCs can lead to increased levels of surface O3 which can significantly impair air quality and cause crop damage. This study focuses on the link between isoprene, surface O3 and carbon dioxide (CO2) over an oil palm plantation and the effects of meteorological factors such as temperature and irradiance on the gas concentrations. The mixing ratios of isoprene, surface O3 and CO2 were measured using a portable gas chromatograph with a photoionization detector called ‘iDirac’, an EcoTech O3 analyser, and LI-COR, respectively. Atmospheric models were used for measured selected gases estimation and validation purposes.Results: Results showed that isoprene and surface O3 had maximum daytime mixing ratios of ~25 ppb and ~57 ppb, respectively. CO2 mixing ratios were high dur...
Atmosphere, 2021
With increasing interest in understanding the contribution of secondary organic aerosol (SOA) to ... more With increasing interest in understanding the contribution of secondary organic aerosol (SOA) to particulate air pollution in urban areas, an exploratory study was carried out to determine levels of carbonaceous aerosols and polycyclic aromatic hydrocarbons (PAHs) in the city of Kuala Lumpur, Malaysia. PM2.5 samples were collected using a high-volume sampler for 24 h in several areas in Kuala Lumpur during the north-easterly monsoon from January to March 2019. Samples were analyzed for water-soluble organic carbon (WSOC), organic carbon (OC), and elemental carbon (EC). Secondary organic carbon (SOC) in PM2.5 was estimated. Particle-bound PAHs were analyzed using gas chromatography-flame ionization detector (GC-FID). Average concentrations of WSOC, OC, and EC were 2.73 ± 2.17 (range of 0.63–9.12) µg/m3, 6.88 ± 4.94 (3.12–24.1) µg/m3, and 3.68 ± 1.58 (1.33–6.82) µg/m3, respectively, with estimated average SOC of 2.33 µg/m3, contributing 34% to total OC. The dominance of char-EC over s...
Environment and Ecology Research, 2021
Environmental Forensics, 2020
Microalgae are unicellular microorganisms with unique features and can be used as indicators for ... more Microalgae are unicellular microorganisms with unique features and can be used as indicators for air pollutants. Microalgae have been found to withstand the negative effects of air pollutants. This study examined the relationship between the levels of carbon monoxide (CO) and the density of microalgal cells in different areas in Peninsular Malaysia, which has a hot and humid climate throughout the year. The influence of CO on the composition of microalgal species was also investigated. Microalgae samples were collected from four selected areas, chosen based on average CO readings for 2015 in the pattern of increasing values (low, medium, high)-Jerantut (low), Banting (medium), Kuala Lumpur (medium) and Petaling Jaya (high). The study found that Desmococcus olivaceus was the most widespread species found in the study areas whereas Trebouxia arboricola was the most dominant species. Trentepohlia rigidula, Coccomyxa confluens, Keratococcus bicaudatus, and Klebsormidium flaccidum can be categorised as non-tolerant to high levels of CO as they were only found in the area with low levels of CO, Jerantut. The study also showed that there was a perfect positive correlation between the CO levels and the number of microalgal cells. Data from the Jaccard Similarity Index indicates a low similarity in species composition between Jerantut and Banting, Kuala Lumpur and Petaling Jaya with Jaccard coefficients of 0.2857, 0.1250, and 0.1250, respectively. The outcomes from this study provide useful data in understanding the relationship of CO on microalgae cell density together with the composition of species and suggest the use of epiphytic microalgae as ecological indicators for air pollution.
With increasing interest in understanding contribution of secondary organic aerosol (SOA) to part... more With increasing interest in understanding contribution of secondary organic aerosol (SOA) to particulate air pollution in urban areas, an exploratory study was carried out to determine levels of carbonaceous aerosols and polycyclic aromatic hydrocarbons (PAHs) in the City of Kuala Lumpur, Malaysia. PM2.5 samples were collected using a high-volume sampler for 24 h in several areas in Kuala Lumpur during the north-easterly monsoon from January to March 2019. Samples were analysed for water soluble organic carbon (WSOC), organic carbon (OC), elemental carbon (EC) and secondary organic carbon (SOC) in PM2.5 was estimated. Particle-bound PAHs were analysed using gas chromatography-flame ionization detector (GC-FID). Average concentrations of WSOC, OC and EC were 2.7 ± 2.2 (range of 0.63-9.1) µg/m3, 6.9 ± 4.9 (3.1-24.1) µg/m3 and 3.7 ± 1.6 (1.3-6.8) µg/m3, respectively, with estimated average SOC of 2.3 µg/m3, contributing 34% to total OC. The average of total PAHs was 1.8 ± 2.7 ng/m3. So...
Sustainability, 2020
Palm oil production is a key industry in tropical regions, driven by the demand for affordable ve... more Palm oil production is a key industry in tropical regions, driven by the demand for affordable vegetable oil. Palm oil production has been increasing by 9% every year, mostly due to expanding biofuel markets. However, the oil palm industry has been associated with key environmental issues, such as deforestation, peatland exploitation and biomass burning that release carbon dioxide (CO2) into the atmosphere, leading to climate change. This review therefore aims to discuss the characteristics of oil palm plantations and their impacts, especially CO2 emissions in the Southeast Asian region. The tropical climate and soil in Southeast Asian countries, such as Malaysia and Indonesia, are very suitable for growing oil palm trees. However, due to the scarcity of available plantation areas deforestation occurs, especially in peat swamp areas. Total carbon losses from both biomass and peat due to the conversion of tropical virgin peat swamp forest into oil palm plantations are estimated to be...
Chemosphere, 2019
This study aims to determine the composition of BTEX (benzene, toluene, ethylbenzene and xylene) ... more This study aims to determine the composition of BTEX (benzene, toluene, ethylbenzene and xylene) and assess the risk to health at different sites in Malaysia. Continuous monitoring of
Geoscience Letters, 2018
Urban air quality has been deteriorating over time. Pollutant distribution levels in the urban en... more Urban air quality has been deteriorating over time. Pollutant distribution levels in the urban environment may be associated with anthropogenic sources and meteorological conditions. The aim of this study is to determine the variation in concentrations of major air pollutants: carbon monoxide (CO), ozone (O 3), nitrogen dioxide (NO 2), sulphur dioxide (SO 2) and particulate matter (PM 10), with corresponding seasonal variation in a Malaysian urban environment. Eleven years of data from four selected stations, namely Klang (S1), Petaling Jaya (S2), Shah Alam (S3) and Cheras (S4), were analysed for temporal trend variations (yearly and monthly). Statistical analysis using Openair, an R package open source software, has been conducted to assess pollutants in relation to meteorological conditions. Gas concentrations showed little variation between the study sites apart from NO 2 , which recorded its highest concentrations at an industrial site, between 23 and 40 ppb, and is associated with industrial and vehicle emissions. Pollutants that show seasonal variations and frequently exceed the Malaysia Ambient Air Quality Standard (MAAQS) and the National Ambient Air Quality Standard (NAAQS) are O 3 and PM 10 , predominantly related to the monsoon seasons. High levels of O 3 during the northeast monsoon (January-March) are associated with high levels of the precursors of O 3. The concentration of PM 10 associated with tropical biomass burning during southwest monsoon. Shipping emissions and power stations are main contributors for higher level of SO 2. This study shows regional and local factors contribute to the different type of air pollutant concentrations in urban environment.
Atmospheric Environment, 2017
Almost every dry season, peatland fires occur in Sumatra and Kalimantan Inlands. Dense smoke haze... more Almost every dry season, peatland fires occur in Sumatra and Kalimantan Inlands. Dense smoke haze from Indonesian peatland fires (IPFs) causes impacts on health, visibility, transport and regional climate in Southeast Asian countries such as Indonesia, Malaysia, and Singapore. Quantitative knowledge of IPF source contribution to ambient aerosols in Southeast Asia (SEA) is so useful to make appropriate suggestions to policy makers to mitigate IPF-induced haze pollution. However, its quantitative contribution to ambient aerosols in SEA remains unclarified. In this study, the source contributions to PM2.5 were determined by the Positive Matrix Factorization (PMF) model with annual comprehensive observation data at Petaling Jaya on the west coast of Peninsular Malaysia, which is downwind of the IPF areas in Sumatra Island, during the dry (southwest monsoon: June-September) season. The average PM2.5 mass concentration during the whole sampling periods (Aug 2011-Jul 2012) based on the PMF and chemical mass closure models was determined as 20-21 μg m −3. Throughout the sampling periods, IPF contributed (on average) 6.1-7.0 μg m −3 to the PM2.5, or ~30% of the retrieved PM2.5 concentration. In particular, the PM2.5 was dominantly sourced from IPF during the southwest monsoon season (51-55% of the total PM2.5 concentration on average). Thus, reducing the IPF burden in the PM2.5 levels would drastically improve the air quality (especially during the southwest monsoon season) around the west coast of Peninsular Malaysia.
Chemosphere, 2018
Distribution, sources and potential health risks of polycyclic aromatic hydrocarbons (PAHs) in PM... more Distribution, sources and potential health risks of polycyclic aromatic hydrocarbons (PAHs) in PM 2.5 collected during different monsoon seasons and haze episode in Kuala Lumpur, Chemosphere,
Atmospheric Environment, 2018
Haze is a common phenomenon afflicting Southeast Asia (SEA), including Malaysia, and has occurred... more Haze is a common phenomenon afflicting Southeast Asia (SEA), including Malaysia, and has occurred almost every year within the last few decades. Haze is associated with high level of air pollutants; it reduces visibility and affects human health in the affected SEA countries. This manuscript aims to review the potential origin, chemical compositions, impacts and mitigation strategies of haze in Malaysia. "Slash and burn" agricultural activities, deforestation and oil palm plantations on peat areas, particularly in Sumatra and Kalimantan, Indonesia were identified as the contributing factors to high intensity combustions that results in transboundary haze in Malaysia. During the southwest monsoon (June to September), the equatorial SEA region experiences a dry season and thus an elevated number of fire events. The prevailing southerly and south-westerly winds allow the cross-boundary transportation of pollutants from the burning areas in Sumatra and Kalimantan in Indonesia, to Peninsular Malaysia and Malaysian Borneo, respectively. The dry periods caused by the El Niño -Southern Oscillation (ENSO) prolong the duration of poor air quality. The size range of particulate matter (PM) in haze samples indicates that haze is dominated by fine particles. Secondary inorganic aerosols (SIA, such as SO42-and NH4+) and organic substances (such as levoglucosan, LG) were the main composition of PM during haze episodes. Local vehicular emissions and industrial activities also contribute to the amount of pollutants and can introduce toxic material such as polyaromatic hydrocarbons (PAHs). Haze episodes have contributed to increasing hospital visits for treatments related to chronic obstructive pulmonary diseases, upper respiratory infections, asthma and rhinitis. Respiratory mortality increased 19% due to haze episodes. Children and senior citizens are more likely to suffer the health impacts of haze. The inpatient cost alone from haze episodes was estimated at around USD 91,000 per year in Malaysia. Almost all economic sectors also experienced losses, with the heaviest losses in the agriculture and tourism sectors. This review suggests several ways forward to reduce haze episodes in SEA and Malaysia. These include economic approaches, research collaborations and science-policy interface. Improving forecasting capabilities can help reduce response time to burning events and subsequently reduce its impacts. Lastly, commitment and involvement by individuals, government agencies, and the entrepreneurial private sectors are crucial to reduce biomass burning (BB) and haze episodes in SEA.
Environmental science and pollution research international, Jan 8, 2017
The Antarctic continent is known to be an unpopulated region due to its extreme weather and clima... more The Antarctic continent is known to be an unpopulated region due to its extreme weather and climate conditions. However, the air quality over this continent can be affected by long-lived anthropogenic pollutants from the mainland. The Argentinian region of Ushuaia is often the main source area of accumulated hazardous gases over the Antarctic Peninsula. The main objective of this study is to report the first in situ observations yet known of surface ozone (O3) over Ushuaia, the Drake Passage, and Coastal Antarctic Peninsula (CAP) on board the RV Australis during the Malaysian Antarctic Scientific Expedition Cruise 2016 (MASEC'16). Hourly O3 data was measured continuously for 23 days using an EcoTech O3 analyzer. To understand more about the distribution of surface O3 over the Antarctic, we present the spatial and temporal of surface O3 of long-term data (2009-2015) obtained online from the World Meteorology Organization of World Data Centre for greenhouse gases (WMO WDCGG). Furt...
Air Quality, Atmosphere & Health, 2017
PM 2.5 released from urban sources and regional biomass fire is of great concern due to the delet... more PM 2.5 released from urban sources and regional biomass fire is of great concern due to the deleterious effect on human health. This study was conducted to determine the chemical compositions andsource apportionment of PM 2.5. Twenty-four-hour PM 2.5 samples were collected at two urban monitoring sites in Kuala Lumpur, Malaysia, from 12 November 2013 to 15 January 2014 using a high volume air sampler (HVS). The source apportionment of PM 2.5 was determined using positive matrix factorization (PMF) version 5.0. Overall, the PM 2.5 mean concentrations ranged from 16 to 55 μg m −3 with a mean of 23 ± 9 μg m −3. The results of enrichment factor (EF) analysis showed that Zn, Pb, As, Cu, Cr, V, Ni, and Cs mainly originated from non-crustal sources. The dominant polycyclic aromatic hydrocarbons (PAHs) were benzo[b]fluoranthene (B[b]F), benzo[ghi]perylene (B[ghi]P), indeno[1,2,3-cd]pyrene (I[cd]P), benzo[a]pyrene (B[a]P) and benzo[k]fluoranthene (B[k]F). PMF 5.0 results showed that the secondary aerosol coupled with biomass burning was the largest contributor followed by combustion of fuel oil and road dust, soil dust source and sea salt and nitrate aerosol, accounting for 34, 25, 24 and 17% of PM 2.5 mass, respectively. On the other hand, biomass and wood burning (42%) was the predominant source of PAHs followed by combustion of fossil fuel (36%) and natural gas and coal burning (22%). The broad overview of the PM 2.5 sources will help to adopt adequate mitigation measures in the management of future urban air quality in this region.
Atmospheric Chemistry and Physics, 2015
In this study, we quantified carbonaceous PM 2.5 in Malaysia through annual observations of PM 2.... more In this study, we quantified carbonaceous PM 2.5 in Malaysia through annual observations of PM 2.5 , focusing on organic compounds derived from biomass burning. We determined organic carbon (OC), elemental carbon and concentrations of solvent-extractable organic compounds (biomarkers derived from biomass burning sources and n-alkanes). We observed seasonal variations in the concentrations of pyrolyzed OC (OP), levoglucosan (LG), mannosan (MN), galactosan, syringaldehyde, vanillic acid (VA) and cholesterol. The average concentrations of OP, LG, MN, galactosan, VA and cholesterol were higher during the southwestern monsoon season (June-September) than during the northeastern monsoon season (December-March), and these differences were statistically significant. Conversely, the syringaldehyde concentration during the southwestern monsoon season was lower. The PM 2.5 OP / OC4 mass ratio allowed distinguishing the seven samples, which have been affected by the Indonesian peatland fires (IPFs). In addition, we observed significant differences in the concentrations between the Indonesian peatland fire (IPF) and other samples of many chemical species. Thus, the chemical characteristics of PM 2.5 in Malaysia appeared to be significantly influenced by IPFs during the southwestern monsoon season. Furthermore, we evaluated two indicators, the vanillic acid / syringic acid (VA / SA) and LG / MN mass ratios, which have been suggested as indicators of IPFs. The LG / MN mass ratio ranged from 14 to 22 in the IPF samples and from 11 to 31 in the other samples. Thus, the respective variation ranges partially overlapped. Consequently, this ratio did not satisfactorily reflect the effects of IPFs in Malaysia. In contrast, the VA / SA mass ratio may serve as a good indicator, since it significantly differed between the IPF and other samples. However, the OP / OC4 mass ratio provided more remarkable differences than the VA / SA mass ratio, offering an even better indicator. Finally, we extracted biomass burning emissions' sources such as IPF, softwood/hardwood burning and meat cooking through varimax-rotated principal component analysis.
Environmental science and pollution research international, Jan 13, 2017
Open biomass burning in Peninsula Malaysia, Sumatra, and parts of the Indochinese region is a maj... more 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 neutr...
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Papers by Mohd Talib Latif