Pharmaceutical compounds in Malaysian urban domestic wastewater

The emerging contaminants (ECs) is detected at trace concentration in the discharge of sewage treatment plant (STP) to the water bodies indicate incomplete removal during the treatment process. The presence of the ECs in the water has a potential impact on the ecological and human health associated with long-term ingestion of the mixture ECs compounds, and this includes the development of resistance in pathogenic bacteria, aquatic toxicity, genotoxicity, and endocrine disruption. In this study, we investigate the presence of ECs and review the occurrence of mainly of four pharmaceutical active compounds belonging to the group of non-steroidal anti-inflammatory drugs (NSAIDs) in influent and effluent of the STP. The target analytes (ibuprofen (IBU), diclofenac (DIC), ketoprofen (KET), and naproxen (NAP)) are extracted from the wastewater using the solid-phase extraction (SPE) followed by the identification and quantification using gas chromatography-mass spectrometry (GC-MS). The GC-MS detection was improved by the derivatisation technique using N-Methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) and an internal standard of Ibuprofen-D3 used as the internal standard. The targeted analytes were detected in both influent and effluent wastewater in the range 5.04±5.9 to 37.4±28.4 μg/L with removal efficiency between 11 - 86% using the current activated sludge treatment process in the STP. This concentration of compounds shows inadequate current treatment techniques to eliminate the emerging contaminants in the wastewater

Assessing Indoor air quality and sick building syndrome in public University buildings: a cross-sectional study of office worker health and well-being

Exposure to indoor air pollution among office workers can result in various health issues and increase the incidence of Sick Building Syndrome (SBS). The aim of the present study was to investigate the effect of exposure to Indoor Air Quality (IAQ) among office workers and the relationship with the prevalence of SBS at Universiti Kebangsaan Malaysia (UKM), Bangi. A cross-sectional comparison research involving 144 office workers from various new and old buildings was carried out at UKM, Bangi. Information was gathered and symptoms associated with SBS were determined using a series of questionnaires. During office hours, IAQ parameters were collected using air quality sensor. The old building had substantially higher levels of NO2 (24.26 ppb), CO (0.62 ppb), and PM10 (4.99 μg/m3) than the new building. It was found that, with a p < 0.001, the concentration of O3 in the new building (11.47 ppb) was significantly higher than in the old building (4.93 ppb). The study’s findings also showed that the difference in temperature between the old buildings (26°C) and new buildings (24°C) was statistically significant (p = 0.003). Referring to relative humidity (RH), the result of the old building is lower (56%) compared to the new building (62%). Although old buildings exhibited a higher prevalence of SBS (34.7%), it was found that there was no significant difference compared to new buildings (27.5%). According to the study’s findings, found that exposure to CO (χ2 = 5.242, p = 0.022), PM10 (χ2 = 13.449, p < 0.001), and PM2.5 (χ2 = 19.755, p < 0.001) among office workers with the prevalence of SBS has significant association. In conclusion, this study suggests that exposure to high levels of CO, PM10 and PM2.5 can increase the prevalence of SBS. Good housekeeping and regular maintenance of ventilation can keep good IAQ and reduce health effects among occupants

Calibration model of a low-cost air quality sensor using an adaptive neuro-fuzzy inference system

Conventional air quality monitoring systems, such as gas analysers, are commonly used in many developed and developing countries to monitor air quality. However, these techniques have high costs associated with both installation and maintenance. One possible solution to complement these techniques is the application of low-cost air quality sensors (LAQSs), which have the potential to give higher spatial and temporal data of gas pollutants with high precision and accuracy. In this paper, we present DiracSense, a custom-made LAQS that monitors the gas pollutants ozone (O3), nitrogen dioxide (NO2), and carbon monoxide (CO). The aim of this study is to investigate its performance based on laboratory calibration and field experiments. Several model calibrations were developed to improve the accuracy and performance of the LAQS. Laboratory calibrations were carried out to determine the zero offset and sensitivities of each sensor. The results showed that the sensor performed with a highly linear correlation with the reference instrument with a response-time range from 0.5 to 1.7 min. The performance of several calibration models including a calibrated simple equation and supervised learning algorithms (adaptive neuro-fuzzy inference system or ANFIS and the multilayer feed-forward perceptron or MLP) were compared. The field calibration focused on O3 measurements due to the lack of a reference instrument for CO and NO2. Combinations of inputs were evaluated during the development of the supervised learning algorithm. The validation results demonstrated that the ANFIS model with four inputs (WE OX, AE OX, T, and NO2) had the lowest error in terms of statistical performance and the highest correlation coefficients with respect to the reference instrument (0.8 < r < 0.95). These results suggest that the ANFIS model is promising as a calibration tool since it has the capability to improve the accuracy and performance of the low-cost electrochemical sensor

Isoprene hotspots at the Western Coast of Antarctic Peninsula during MASEC′16

Isoprene (C5H8) plays an important role in the formation of surface ozone (O3) and the secondary organic aerosol (SOA) which contributed to the climate change. This study aims to determine hourly distribution of tropospheric isoprene over the Western Coast of Antarctic Peninsula (WCAP) during the Malaysian Antarctic Scientific Expedition Cruise 2016 (MASEC′16). In-situ measurements of isoprene were taken using a custom-built gas chromatography with photoionization detector, known as iDirac. Biological parameters such as chlorophyll a (chl-a) and particulate organic carbon (POC) were compared to the in-situ isoprene measurements. Significant positive correlation was observed between isoprene and POC concentrations (r2 = 0.67, p < 0.001), but not between isoprene and chl-a. The hotspots of isoprene over maritime Antarctic were then were investigated using NAME dispersion model reanalysis. Measurements showed that isoprene mixing ratio were the highest over region of King George Island, Deception Island and Booth Island with values of ∼5.0, ∼0.9 and ∼5.2 ppb, respectively. Backward trajectory analysis showed that air masses may have lifted the isoprene emitted by marine algae. We believe our findings provide valuable data set of isoprene estimation over the under sampled WCAP

Distribution of Gas Phase Polycyclic Aromatic Hydrocarbons (PAHs) in Selected Indoor and Outdoor Air Samples of Malaysia: a Case Study in Serdang, Selangor and Bachang, Malacca

Distribution of 10 polycyclic aromatic hydrocarbons (PAHs) in the gas phase of air from selected indoor and outdoor areas of Selangor and Malacca, Malaysia has been investigated. A locally designed Semi Permeable Membrane Device (SPMD) was applied for passive air sampling for 37 days at selected locations. Cleanup was carried out with Gas Purge - Micro Syringe Extraction (GP-MSE) and the final analysis was using Gas Chromatography-Mass Spectrometry (GC-MS). In this study, 6 indoor and 12 outdoor locations were selected for air sampling. A total of 10 compounds of PAHs (Ʃ10PAHs) were determined in the range of 0.218 ng/m3 - 1.692 ng/m3 and 0.378 ng/m3 - 1.492 ng/m3 in outdoor and indoor samples respectively. In the outdoor samples, locations such as near a petrol station and heavy traffic showed the maximum levels of Ʃ10PAHs, while rooftop samples showed the lowest Ʃ10PAHs. The distribution of gas phase Ʃ10PAHs was influenced by vehicular emission. Low molecular weight (LMW) compounds (2-3 rings) were dominant in all samples (>70%) indicating that SPMD has successfully sampled the gas phase of the air

Rekod jangka panjang kepekatan metana di Malaysia

Gas metana (CH4) adalah gas rumah hijau yang menyebabkan perubahan iklim dan pemanasan dunia. Kajian CH4 dijalankan untuk melihat tren pelepasan CH4 di Malaysia dalam satu jangka masa yang panjang (10 tahun) dari tahun 2000 hingga 2009 dan menilai hubungan CH4 dengan ozon permukaan (O3). Data CH4 daripada 19 stesen pemantauan kualiti udara automatik berterusan Jabatan Alam Sekitar (JAS) di Malaysia telah dianalisis menggunakan analisis statistik dan korelasi Pearson. Hasil kajian mendapati nilai bacaan kepekatan purata bulanan CH4 tertinggi dicatatkan di stesen Larkin, Johor Bahru iaitu 2.61±0.54 ppm. Nilai purata kepekatan CH4 berdasarkan data yang direkodkan di semua stesen di Malaysia adalah 2.00 ppm. Taburan kepekatan CH4 yang lebih tinggi didapati tertumpu di kawasan bandar dan kawasan perindustrian di Selangor, Melaka dan Johor. Analisis korelasi bagi menentukan hubungan CH4 dengan bahan pencemar O3 mendapati 15 stesen menunjukkan korelasi positif yang sangat kecil dan lemah (r 0.05). Stesen Shah Alam didapati menunjukkan korelasi CH4 paling tinggi dengan O3 berbanding stesen lain. Pengetahuan asas berkenaan CH4 dalam udara ambien Malaysia yang ditunjukkan dalam kajian ini boleh digunakan untuk menilai potensi impak CH4 terhadap alam sekitar, perubahan iklim dan kesihatan manusia

Volatile organic compounds and their contribution to ground-level ozone formation in a tropical urban environment

This study aims to determine the trends of volatile organic compound (VOC) concentrations and their potential contribution to O3 formation. The hourly data (August 2017 to July 2018) for 29 VOCs were obtained from three Malaysian Department of Environment continuous air quality monitoring stations with different urban backgrounds (Shah Alam, Cheras, Seremban). The Ozone Formation Potential (OFP) was calculated based on the individual Maximum Incremental Reactivity (MIR) and VOC concentrations. The results showed that the highest mean total VOC concentrations were recorded at Cheras (148 ± 123 μg m−3), within the Kuala Lumpur urban environment, followed by Shah Alam (124 ± 116 μg m−3) and Seremban (86.4 ± 89.2 μg m−3). VOCs such as n-butane, ethene, ethane and toluene were reported to be the most abundant species at all the selected stations, with overall mean concentrations of 16.6 ± 11.9 μg m−3, 12.1 ± 13.3 μg m−3, 10.8 ± 11.9 μg m−3 and 9.67 ± 9.00 μg m−3, respectively. Alkenes (51.3–59.1%) and aromatic hydrocarbons (26.4–33.5%) have been identified as the major contributors to O3 formation in the study areas based on the overall VOC measurements. Relative humidity was found to influence the concentrations of VOCs more than other meteorological parameters. Overall, this study will contribute to further understanding of the distribution of VOCs and their contribution to O3 formation, particularly in the tropical urban environment

Risk Assessment and Air Quality Study during Different Phases of COVID-19 Lockdown in an Urban Area of Klang Valley, Malaysia

Globally, the COVID-19 pandemic has had both positive and negative impacts on humans and the environment. In general, a positive impact can be seen on the environment, especially in regard to air quality. This positive impact on air quality around the world is a result of movement control orders (MCO) or lockdowns, which were carried out to reduce the cases of COVID-19 around the world. Nevertheless, data on the effects on air quality both during and post lockdown at local scales are still sparse. Here, we investigate changes in air quality during normal days, the MCOs (MCO 1, 2 and 3) and post MCOs, namely the Conditional Movement Control Order (CMCO) and the Recovery Movement Control Order (RMCO) in the Klang Valley region. In this study, we used the air sensor network AiRBOXSense that measures carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2) and particulate matter (PM2.5 and PM10) at Petaling Jaya South (PJS), Kelana Jaya (KJ) and Kota Damansara (KD). The results showed that the daily average concentrations of CO and NO2 mostly decreased in the order of normal days &gt; MCO (MCO 1, 2 and 3) &gt; CMCO &gt; RMCO. PM10, PM2.5, SO2 and O3 showed a decrease from the MCO to RMCO. PJS showed that air pollutant concentrations decreased from normal days to the lockdown phases. This clearly shows the effects of ‘work from home’ orders at all places in the PJS city. The greatest percentage reductions in air pollutants were observed during the change from normal days to MCO 1 (24% to 64%), while during MCO 1 to MCO 2, the concentrations were slightly increased during the changes of the lockdown phase, except for SO2 and NO2 over PJS. In KJ, most of the air pollutants decreased from MCO 1 to MCO 3 except for CO. However, the percentage reduction and increments of the gas pollutants were not consistent during the different phases of lockdown, and this effect was due to the sensor location—only 20 m from the main highway (vehicle emissions). The patterns of air pollutant concentrations over the KD site were similar to the PJS site; however, the percentage reduction and increases of PM2.5, O3, SO2 and CO were not consistent. We believe that local burning was the main contribution to these unstable patterns during the lockdown period. The cause of these different changes in concentrations may be due to the relaxation phases during the lockdown at each station, where most of the common activities, such as commuting and industrial activities changed in frequency from the MCO, CMCO and RMCO. Wind direction also affected the concentrations, for example, during the CMCO and RMCO, most of the pollutants were blowing in from the Southeast region, which mostly consists of a city center and industrial areas. There was a weak correlation between air pollutants and the temperature and relative humidity at all stations. Health risk assessment analysis showed that non-carcinogenic risk health quotient (HQ) values for the pollutants at all stations were less than 1, suggesting unlikely non-carcinogenic effects, except for SO2 (HQ &gt; 1) in KJ. The air quality information showed that reductions in air pollutants can be achieved if traffic and industry emissions are strictly controlled