A floating chamber system for VOC sea-to-air flux measurement near the sea surface.

Volatile organic compounds (VOCs) form ozone (O3) and secondary organic aerosols (SOAs) in the atmosphere under favourable conditions. Biogenic VOC levels in the marine atmosphere are significantly lower compared with levels in the atmosphere above terrestrial ecosystems. However, much less is known about the marine biogenic VOC sea-to-air flux, specifically at the sea surface level. Therefore, here we describe a newly developed and cost-effective floating chamber system that has the capacity to measure the VOC sea-to-air flux near the sea surface (< 1 m). The floating chamber is coupled with adsorbent cartridges, and samples were analysed in the laboratory using commercial thermal desorption and gas chromatography mass spectrometry (TD-GC-MS). The structural performance of the floating flux chamber was evaluated, and it was shown to have the capacity to stay continuously afloat for up to 72 h in various conditions (e.g., rainy, windy) and with wave heights up to approximately 1 m in coastal waters. Preliminary measurements of isoprene (3-Methyl-1,2-butadiene) (C5H8) sea-to-air flux using the floating flux chamber in the coastal waters off the east coast of Peninsular Malaysia found values in the region of 107 molecules/cm2/s, comparable with most published values based on various flux measurement techniques. We suggest the proposed floating chamber system could serve as a cost-effective VOC flux technique that allows measurements near the sea surface.

PM2.5 and ozone in office environments and their potential impact on human health.

It is important to have good indoor air quality, especially in indoor office environments, in order to enhance productivity and maintain good work performance. This study investigated the effects of indoor office activities on particulate matter of less than 2.5 µm (PM2.5) and ozone (O3) concentrations, assessing their potential impact on human health. Measurements of indoor PM2.5 and O3 concentrations were taken every 24 h during the working days in five office environments located in a semi-urban area. As a comparison, the outdoor concentrations were derived from the nearest Continuous Air Quality Monitoring Station. The results showed that the average 24 h of indoor and outdoor PM2.5 concentrations were 3.24 ± 0.82 µg m-3 and 17.4 ± 3.58 µg m-3 respectively, while for O3 they were 4.75 ± 4.52 ppb and 21.5 ± 5.22 ppb respectively. During working hours, the range of PM2.5 concentrations were 1.00 µg m-3 to 6.10 µg m-3 while for O3 they were 0.10 ppb to 38.0 ppb. The indoor to outdoor ratio (I/O) for PM2.5 and O3 was <1, thus indicating a low infiltration of outdoor sources. The value of the hazard quotient (HQ) for all sampling buildings was <1 for both chronic and acute exposures, indicating that the non-carcinogenic risks are negligible. Higher total cancer risk (CR) value for outdoors (2.67E-03) was observed compared to indoors (4.95E-04) under chronic exposure while the CR value for acute exposure exceeded 1.0E-04, thus suggesting a carcinogenic PM2.5 risk for both the indoor and outdoor environments. The results of this study suggest that office activities, such as printing and photocopying, affect indoor O3 concentrations while PM2.5 concentrations are impacted by indoor-related contributions.

Observations of BTEX in the ambient air of Kuala Lumpur by passive sampling.

Benzene, toluene, ethylbenzene and xylenes (BTEX) are well known hazardous volatile organic compounds (VOCs) due to their human health risks and photochemical effects. The main objective of this study was to estimate BTEX levels and evaluate interspecies ratios and ozone formation potentials (OFP) in the ambient air of urban Kuala Lumpur (KL) based on a passive sampling method with a Tenax® GR adsorbent tube. Analysis of BTEX was performed using a thermal desorption (TD)-gas chromatography mass spectrometer (GCMS). OFP was calculated based on the Maximum Incremental Reactivity (MIR). Results from this study showed that the average total BTEX during the sampling period was 66.06 ± 2.39 µg/m3. Toluene (27.70 ± 0.97 µg/m3) was the highest, followed by m,p-xylene (13.87 ± 0.36 µg/m3), o-xylene (11.49 ± 0.39 µg/m3), ethylbenzene (8.46 ± 0.34 µg/m3) and benzene (3.86 ± 0.31 µg/m3). The ratio of toluene to benzene (T:B) is > 7, suggesting that VOCs in the Kuala Lumpur urban environment are influenced by vehicle emissions and other anthropogenic sources. The average of ozone formation potential (OFP) value from BTEX was 278.42 ± 74.64 µg/m3 with toluene and xylenes being the major contributors to OFP. This study also indicated that the average of benzene concentration in KL was slightly lower than the European Union (EU)-recommended health limit value for benzene of 5 µg/m3 annual exposure.

Recent Trend in Specialty Choices of Medical Students and House Officers from Public Sector Medical Universities, Karachi.

OBJECTIVE: To determine career choices of medical students of public-sector medical universities and factors affecting their career choices. METHODS: The cross-sectional study was conducted at Dow University of Health Sciences and Jinnah Sindh Medical University, Karachi, from May 2015 to May 2016, and comprised 4th and 5th year medical students and house officers. A self-administrated structured questionnaire was used to collect data which was entered and analysed using SPSS 20. RESULTS: Of the 445 Subjects, 314(70.6%) were females. There were 206(46.3%) 4th year students, 194(43.6%) were from the 5th year and 45(10%) were house officers. Top 15 medical specialties were ranked according to the respondents' top three choices. Internal medicine 67(15.1%), cardiology 47(10.6%), paediatrics 46(10.3%) and general surgery 40(9.0%) were the four highest ranked specialties. Overall, 377(84.7%) subjects said prestige in working in that field was the reason of their respective choices. CONCLUSIONS: Medical students chose a wider range of specialties and stated varying factors affecting their choices.

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.

Determination and risk assessment of pharmaceutical residues in the urban water cycle in Selangor Darul Ehsan, Malaysia.

The environmental fate of non-steroidal anti-inflammatory drugs (NSAIDs) in the urban water cycle is still uncertain and their status is mainly assessed based on specific water components and information on human risk assessments. This study (a) explores the environmental fate of NSAIDs (ibuprofen, IBU; naproxen, NAP; ketoprofen, KET; diazepam, DIA; and diclofenac, DIC) in the urban water cycle, including wastewater, river, and treated water via gas chromatography-mass spectrophotometry (GCMS), (b) assesses the efficiency of reducing the targeted NSAIDs in sewage treatment plant (STP) using analysis of variance (ANOVA), and (c) evaluates the ecological risk assessment of these drugs in the urban water cycle via teratogenic index (TI) and risk quotient (RQ). The primary receptor of contaminants comes from urban areas, as a high concentration of NSAIDs is detected (ranging from 5.87 × 103 to 7.18 × 104 ng/L). The percentage of NSAIDs removal in STP ranged from 25.6% to 92.3%. The NAP and KET were still detected at trace levels in treated water, indicating the persistent presence in the water cycle. The TI values for NAP and DIA (influent and effluent) were more than 1, showing a risk of a teratogenic effect. The IBU, KET, and DIC had values of less than 1, indicating the risk of lethal embryo effects. The NAP and DIA can be classified as Human Pregnancy Category C (2.1 > TI ≥ 0.76). This work proved that these drugs exist in the current urban water cycle, which could induce adverse effects on humans and the environment (RQ in high and low-risk categories). Therefore, they should be minimized, if not eliminated, from the primary sources of the pollutant (i.e., STPs). These pollutants should be considered a priority to be monitored, given focus to, and listed in the guideline due to their persistent presence in the urban water cycle.

Spatial-temporal variability and heath impact of particulate matter during a 2019-2020 biomass burning event in Southeast Asia.

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 respiratory tract showed a higher total deposition fraction value during haze days than on non-haze days. The result from this study indicated that Malaysia and Thailand are highly affected by biomass burning activity during the dry seasons and the Southwest monsoon.

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.

The concentration of BTEX in selected urban areas of Malaysia during the COVID-19 pandemic lockdown.

Volatile organic compounds (VOCs) such as benzene, toluene, ethylbenzene and xylene (BTEX) are air pollutants that harm human health. This study aims to identify BTEX concentrations before the lockdown known as the Movement Control Order was imposed (BMCO), during the implementation of the Movement Control Order (MCO), and then during the Conditional Movement Control Order (CMCO). These orders were introduced during the COVID-19 pandemic in Malaysia. The study utilised data measured by the continuous monitoring of BTEX using online gas chromatography instruments located at three urban area stations. The results showed that the BTEX concentrations reduced by between -38% and -46% during the MCO compared to the BMCO period. The reduction of human mobility during the MCO and CMCO influenced the lower BTEX concentrations recorded at a station within the Kuala Lumpur area. The results of the BTEX diagnostic ratios and principal component analysis showed that the major source of BTEX, especially during the BMCO and CMCO periods, was motor vehicle emissions. Further investigation, using correlation analysis and polar plots, showed that the BTEX concentrations were also influenced by meteorological variables such as wind speed, air temperature and relative humidity.

Seasonal variation and size distribution of inorganic and carbonaceous components, source identification of size-fractioned urban air particles in Kuala Lumpur, Malaysia.

This study aims to determine the inorganic and carbonaceous components depending on the seasonal variation and size distribution of urban air particles in Kuala Lumpur. Different fractions of particulate matter (PM) were measured using a Nanosampler from 17 February 2017 until 27 November 2017. The water-soluble inorganic ions (WSIIs) and carbonaceous components in all samples were analysed using ion chromatography and carbon analyser thermal/optical reflectance, respectively. Total PM concentration reached its peak during the southwest (SW) season (70.99 ± 6.04 µg/m3), and the greatest accumulation were observed at PM0.5-1.0 (22%-30%, 9.55 ± 1.03 µg/m3) and PM2.5-10 (22%-25%, 10.34 ± 0.81 µg/m3). SO42-, NO3- and NH4+ were major contributors of WSIIs, and their formation was favoured mainly during SW season (80.5% of total ions). PM0.5-1.0 and PM2.5-10 exhibited the highest percentage of WSII size distribution, accounted for 28.4% and 13.5% of the total mass, respectively. The average contribution of carbonaceous species (OC + EC) to total carbonaceous concentrations were higher in PM0.5-1.0 (35.2%) and PM2.5-10 (26.6%). Ultrafine particles (PM<0.1) consistently indicated that the sources were from vehicle emission while the SW season was constantly dominated by biomass burning sources. Using the positive matrix factorization (PMF) model, secondary inorganic aerosol and biomass burning (30.3%) was known as a significant source of overall PM. As a conclusion, ratio and source apportionment indicate the mixture of biomass burning, secondary inorganic aerosols and motor vehicle contributed to the size-segregated PM and seasonal variation of inorganic and carbonaceous components of urban air particles.

The occurrence of non-steroidal anti-inflammatory drugs (NSAIDs) in Malaysian urban domestic wastewater.

The water stream has been reported to contain non-steroidal anti-inflammatory drugs (NSAIDs), released from households and premises through discharge from Sewage Treatment Plant (STP). This research identifies commonly consumed NSAIDs namely ibuprofen (IBU), diclofenac (DIC), ketoprofen (KET) and naproxen (NAP) in the influent wastewater from two urban catchments (i.e. 2 STPs). We expand our focus to assess the efficiency of monomer (C18) and dimer (HLB) types of sorbents in the solid phase extraction method followed by gas chromatography mass spectrometry (GCMS) analysis and optimize model prediction of NSAIDs in the influent wastewater using I-Optimal design. The ecological risk assessment of the NSAIDs was evaluated. The HLB produced reliable analysis for all NSAIDs under study (STP1: 6.7 × 10-3 mg L-1 to 2.21 × 10-1 mg L-1, STP2: 1.40 × 10-4 mg L-1 to 9.72 × 10-2 mg L-1). The C18 however, selective to NAP. Based on the Pearson proximity matrices, the DICHLB can be a good indicator for IBUHLB (0.565), NAPC18 (0.721), NAPHLB (0.566), and KETHLB (0.747). The optimized model prediction for KET and NAP based on DIC are successfully validated. The risk quotients (RQ) values of NSAIDs were classified as high (RQ > 1), medium (RQ, 0.1-1) and low (RQ, 0.01-0.1) risks. The optimized models are beneficial for major NSAIDs (KET and NAP) monitoring in the influent wastewater of urban domestic area. An upgrade on the existing wastewater treatment infrastructure is recommended to counteract current water security situation.

Ambient volatile organic compounds in tropical environments: Potential sources, composition and impacts - A review.

Volatile organic compounds (VOCs) are widely recognized to affect the environment and human health. This review provides a comprehensive presentation of the types and levels of VOCs, their sources and potential effects on human health and the environment based on past and current observations made at tropical sites. Isoprene was found to be the dominant biogenic VOC in the tropics. Tropical broad leaf evergreen trees are the main emitters of isoprene, making up more than 70% of the total emissions. The VOCs found in the tropical remote marine atmosphere included isoprene (>100 ppt), dimethyl sulfide (≤100 ppt) and halocarbons, i.e. bromoform (≤8.4 ppt), dibromomethane (≤2.7 ppt) and dibromochloromethane (≤1.6 ppt). VOCs such as benzene, toluene, ethylbenzene and xylene (BTEX) are the most monitored anthropogenic VOCs and are present mainly due to motor vehicles emissions. Additionally, biomass burning contributes to anthropogenic VOCs, especially high molecular weight VOCs, e.g. methanol and acetonitrile. The relative contributions of VOC species to ozone are determined through the level of the Ozone Formation Potential (OFP) of different species. Emissions of VOCs (e.g. very short-lived halogenated gases) in the tropics are capable of contributing to stratospheric ozone depletion. BTEX has been identified as the main types of VOCs that are associated with the cancer risk in urban areas in tropical regions. Finally, future studies related to VOCs in the tropics and their associated health risks are needed to address these concerns.

Modeling aerosol transmission of SARS-CoV-2 from human-exhaled particles in a hospital ward.

The COVID-19 pandemic has plunged the world into uncharted territory, leaving people feeling helpless in the face of an invisible threat of unknown duration that could adversely impact the national economic growths. According to the World Health Organization (WHO), the SARS-CoV-2 spreads primarily through droplets of saliva or discharge from the mouth or nose when an infected person coughs or sneezes. However, the transmission of the SARS-CoV-2 through aerosols remains unclear. In this study, computational fluid dynamic (CFD) is used to complement the investigation of the SARS-CoV-2 transmission through aerosol. The Lagrangian particle tracking method was used to analyze the dispersion of the exhaled particles from a SARS-CoV-2-positive patient under different exhale activities and different flow rates of chilled (cooling) air supply. Air sampling of the SARS-CoV-2 patient ward was conducted for 48-h measurement intervals to collect the indoor air sample for particulate with diameter less than 2.5 µm. Then, the reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) was conducted to analyze the collected air sample. The simulation demonstrated that the aerosol transmission of the SARS-CoV-2 virus in an enclosed room (such as a hospital ward) is highly possible.

Spatial distribution of fine and coarse particulate matter during a southwest monsoon in Peninsular Malaysia.

This study aimed to determine the spatial distribution of PM2.5 and PM10 collected in four regions (North, Central, South and East Coast) of Peninsular Malaysia during the southwest monsoon. Concurrent measurements of PM2.5 and PM10 were performed using a high volume sampler (HVS) for 24 h (August to September 2018) collecting a total of 104 samples. All samples were then analysed for water soluble inorganic ions (WSII) using ion chromatography, trace metals using inductively coupled plasma-mass spectroscopy (ICP-MS) and polycyclic aromatic hydrocarbon (PAHs) using gas chromatography-mass spectroscopy (GC-MS). The results showed that the highest average PM2.5 concentration during the sampling campaign was in the North region (33.2 ± 5.3 µg m-3) while for PM10 the highest was in the Central region (38.6 ± 7.70 µg m-3). WSII recorded contributions of 22% for PM2.5 and 20% for PM10 mass, with SO42- the most abundant species with average concentrations of 1.83 ± 0.42 µg m-3 (PM2.5) and 2.19 ± 0.27 µg m-3 (PM10). Using a Positive Matrix Factorization (PMF) model, soil fertilizer (23%) was identified as the major source of PM2.5 while industrial activity (25%) was identified as the major source of PM10. Overall, the studied metals had hazard quotients (HQ) value of <1 indicating a very low risk of non-carcinogenic elements while the highest excess lifetime cancer risk (ELCR) was recorded for Cr VI in the South region with values of 8.4E-06 (PM2.5) and 6.6E-05 (PM10). The incremental lifetime cancer risk (ILCR) calculated from the PAH concentrations was within the acceptable range for all regions.

Particulate matter (PM2.5) as a potential SARS-CoV-2 carrier.

The rapid spread of the SARS-CoV-2 in the COVID-19 pandemic had raised questions on the route of transmission of this disease. Initial understanding was that transmission originated from respiratory droplets from an infected host to a susceptible host. However, indirect contact transmission of viable virus by fomites and through aerosols has also been suggested. Herein, we report the involvement of fine indoor air particulates with a diameter of ≤ 2.5 µm (PM2.5) as the virus's transport agent. PM2.5 was collected over four weeks during 48-h measurement intervals in four separate hospital wards containing different infected clusters in a teaching hospital in Kuala Lumpur, Malaysia. Our results indicated the highest SARS-CoV-2 RNA on PM2.5 in the ward with number of occupants. We suggest a link between the virus-laden PM2.5 and the ward's design. Patients' symptoms and numbers influence the number of airborne SARS-CoV-2 RNA with PM2.5 in an enclosed environment.

Laparoscopic cholecystectomy: an experience at Lady Reading Hospital, Peshawar.

BACKGROUND: Laparoscopic Cholecystectomy originally a minimal invasive surgical technique involving less hospital stay less economical burden decreased post op complication and early mobility. The objective was to analyse data of patients undergoing laparoscopic cholecystectomy at a surgical setup. METHODS: This study was conducted at the Department of Surgery, Lady Reading Hospital, Peshawar from 11th January 2006 till 10th January 2009. Patients aged above 14 year, presenting in the outpatient department with clinical and ultrasonographic evidence of cholecystitis and undergoing laparoscopic cholecystectomy were included in the study. The procedure performed was predominantly the four port technique for laparoscopic cholecystectomy. A proforma was prepared to collect preoperative, operative, and postoperative data. Operative data included the technique used and the difficulties ascertained during those procedures. Data was analysed using SPSS-13.0. RESULTS: Of 421 patients, 387 patients fulfilled the criteria for admission to undergo the procedure. The mean age of all patients was 38.6 +/- 7.1 year ranging from 16 years to 72 year with a male to female ratio of 1:8.09. During the first six months 57 patients underwent the procedure for which the mean operating time was 67.4 min. During the last six months the mean operating time was 39.1 +/- 8.9 minutes. The overall rate of conversion of laparoscopic cholecystectomy was 6.4%. In comparison the last six months of the study showed one case (1.16%) in 86 patients being converted to open cholecystectomy. The most common cause foe conversion of the laparoscopic procedure to an open cholecystectomy was dense adhesions making dissection of the triangle of Calot's difficult. In 73 cases (21.4%) the gall bladder was perforated during dissection of gall bladder from the gall bladder bed. CONCLUSION: The out comes of this study during the last six months is comparable to studies conducted at more experienced centres making laparoscopic more than just an early experience in this part of the world.

Indoor generated PM2.5 compositions and volatile organic compounds: Potential sources and health risk implications.

The aim of the present study was to investigate the potential sources of heavy metals in fine air particles (PM2.5) and benzene, toluene, ethylbenzene, and isomeric xylenes (BTEX) in gas phase indoor air. PM2.5 samples were collected using a low volume sampler. BTEX samples were collected using passive sampling onto sorbent tubes and analyzed using gas chromatography-mass spectrometry (GC-MS). For the lower and upper floors of the evaluated building, the concentrations of PM2.5 were 96.4 ± 2.70 µg/m3 and 80.2 ± 3.11 µg/m3, respectively. The compositions of heavy metals in PM2.5 were predominated by iron (Fe), zinc (Zn), and aluminum (Al) with concentration of 500 ± 50.07 ng/m3, 466 ± 77.38 ng/m3, and 422 ± 147.38 ng/m3. A principal component analysis (PCA) showed that the main sources of BTEX were originated from vehicle emissions and exacerbate because of temperature variations. Hazard quotient results for BTEX showed that the compounds were below acceptable limits and thus did not possess potential carcinogenic risks. However, a measured output of lifetime cancer probability revealed that benzene and ethylbenzene posed definite carcinogenic risks. Pollutants that originated from heavy traffic next to the sampling site contributed to the indoor pollution.

BTEX compositions and its potential health impacts in Malaysia.

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 BTEX in Kuala Lumpur City Centre, Kuala Terengganu, Kota Kinabalu and Fraser Hill were conducted using Online Gas Chromatograph. For comparison, BTEX at selected hotspot locations were determined by active sampling method using sorbent tubes and Thermal Desorption Gas Chromatography Mass Spectrometry. The hazard quotient (HQ) for non-carcinogenic and the life-time cancer risk (LTCR) of BTEX were calculated using the United States Environmental Protection Agency (USEPA) health risk assessment (HRA) methods. The results showed that the highest total BTEX concentrations using continuous monitoring were recorded in the Kuala Lumpur City Centre (49.56 ±â€¯23.71 µg/m3). Toluene was the most dominant among the BTEX compounds. The average concentrations of benzene ranged from 0.69 ±â€¯0.45 µg/m3 to 6.20 ±â€¯3.51 µg/m3. Measurements using active sampling showed that BTEX concentrations dominated at the roadside (193.11 ±â€¯114.57 µg/m3) in comparison to petrol station (73.08 ±â€¯30.41 µg/m3), petrochemical industry (32.10 ±â€¯13.13 µg/m3) and airport (25.30 ±â€¯6.17 µg/m3). Strong correlations among BTEX compounds (p<0.01, r>0.7) at Kuala Lumpur City Centre showed that BTEX compounds originated from similar sources. The values of HQ at all stations were <1 indicating the non-carcinogenic risk are negligible and do not pose threats to human health. The LTCR value based on benzene inhalation (1.59 × 10-5) at Kuala Lumpur City Centre were between 1 × 10-4 and 1 × 10-5, representing a probable carcinogenic risk.

Early outcome of Lichtenstein technique of tension-free open mesh repair for inguinal hernia.

BACKGROUND: To evaluate the early outcome of Lichtenstein's technique for repair of inguinal hernia using polypropylene mesh. METHODS: This was a descriptive study conducted over a period of twelve months from 1st July 2007 to 30th June 2008 in Surgical 'B' unit, Lady Reading Hospital, Peshawar. One hundred and twelve patients were received through the out patient department with diagnosis of inguinal hernia. Inclusion criteria was patients above the age of 18 years, reducible hernia, evidence of swelling in groin > 2 months. Exclusion criteria was age less than 18 years, chronic constipation, chronic cough, symptoms of prostatism, irreducible hernia, obstructed hernia, strangulated hernia and patients with diabetes mellitus. All the patients were subjected to inguinal mesh repair using the Lichtenstein technique with polypropylene mesh. RESULTS: Mean age of patients was 48.78 +/- 14.41 years. Sixty patients (53.6%) had right sided inguinal hernia while 46 patients (41.1%) had a left sided hernia and 6 patients (5.4%) had bilateral hernia. Sixty two patients (55.4%) had indirect hernia and 43 (38.4%) cases had direct hernia. Sixteen cases (14.3%) had previous history of surgery for hernia on the same side (recurrent hernia). Mild pain was observed in 53 cases (47.3%), moderate pain in 42 cases (37.5%), and severe pain in 17 cases (15.2%). Four patients (3.6%) in all developed a seroma Two patients (1.8%) developed a haematoma that required drainage. Three patients (2.7%) had a prolonged recovery and presented with abdominal distension. Five cases presented with infected wounds. CONCLUSION: Lichtenstein's technique of inguinal mesh repair is a safe and effective procedure but emerging trends anticipates the implementation of day case surgery.

Spatial-temporal variations in surface ozone over Ushuaia and the Antarctic region: observations from in situ measurements, satellite data, and global models.

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). Furthermore, surface O3 satellite data from the free online NOAA-Atmospheric Infrared Sounder (AIRS) database and online data assimilation from the European Centre for Medium-Range Weather Forecasts (ECMWF)-Monitoring Atmospheric Composition and Climate (MACC) were used. The data from both online products are compared to document the data sets and to give an indication of its quality towards in situ data. Finally, we used past carbon monoxide (CO) data as a proxy of surface O3 formation over Ushuaia and the Antarctic region. Our key findings were that the surface O3 mixing ratio during MASEC'16 increased from a minimum of 5 ppb to ~ 10-13 ppb approaching the Drake Passage and the Coastal Antarctic Peninsula (CAP) region. The anthropogenic and biogenic O3 precursors from Ushuaia and the marine region influenced the mixing ratio of surface O3 over the Drake Passage and CAP region. The past data from WDCGG showed that the annual O3 cycle has a maximum during the winter of 30 to 35 ppb between June and August and a minimum during the summer (January to February) of 10 to 20 ppb. The surface O3 mixing ratio during the summer was controlled by photochemical processes in the presence of sunlight, leading to the depletion process. During the winter, the photochemical production of surface O3 was more dominant. The NOAA-AIRS and ECMWF-MACC analysis agreed well with the MASEC'16 data but twice were higher during the expedition period. Finally, the CO past data showed the surface O3 mixing ratio was influenced by the CO mixing ratio over both the Ushuaia and Antarctic regions. Peak surface O3 and CO hourly mixing ratios reached up to ~ 38 ppb (O3) and ~ 500 ppb (CO) over Ushuaia. High CO over Ushuaia led to the depletion process of surface O3 over the region. Monthly CO mixing ratio over Antarctic (South Pole) were low, leading to the production of surface O3 over the Antarctic region.