Gaseous Pollutants Emission from Diesel Vehicles in Hong Kong

The current study presents the detailed investigation of diesel vehicles emissions utilizing chassis dynamometer test in Hong Kong. Gaseous pollutants from diesel vehicle exhaust, including nitrogen oxides (NOx), total hydrocarbon (THC) and carbon monoxide (CO), are chosen to be the targets of this study. These pollutants were monitored real-time during different testing cycles and the data collected were used to calculate the fuel-based emission factor of each pollutant. Results showed that emission standard and driving conditions are the two main factors governing the trend of emission of these pollutants. Outliers observed in these trends are probably caused by the difference in level of maintenance of the vehicles, which is another important factor affecting the emission of pollutants

Prescribing patterns of antidepressants, antipsychotics and mood stabilizers in bipolar patients misdiagnosed with major depressive disorder in China

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94515/1/hup2262.pd

Demographic and Clinical Features and Prescribing Patterns of Psychotropic Medications in Patients with the Melancholic Subtype of Major Depressive Disorder in China

BACKGROUND: Little has been known about the demographic and clinical features of the melancholic subtype of major depressive disorder (MDD) in Chinese patients. This study examined the frequency of melancholia in Chinese MDD patients and explored its demographic and clinical correlates and prescribing patterns of psychotropic drugs. METHODS: A consecutively collected sample of 1,178 patients with MDD were examined in 13 psychiatric hospitals or psychiatric units of general hospitals in China nationwide. The cross-sectional data of patients' demographic and clinical characteristics and prescriptions of psychotropic drugs were recorded using a standardized protocol and data collection procedure. The diagnosis of the melancholic subtype was established using the Mini International Neuropsychiatric Interview (MINI). Medications ascertained included antidepressants, mood stabilizers, antipsychotics and benzodiazepines. RESULTS: Six hundred and twenty nine (53.4%) of the 1,178 patients fulfilled criteria for melancholia. In multiple logistic regression analyses, compared to non-melancholic counterparts, melancholic MDD patients were more likely to be male and receive benzodiazepines, had more frequent suicide ideations and attempts and seasonal depressive episodes, while they were less likely to be employed and receive antidepressants and had less family history of psychiatric disorders and lifetime depressive episodes. CONCLUSIONS: The demographic and clinical features of melancholic MDD in Chinese patients were not entirely consistent with those found in Western populations. Compared to non-melancholic MDD patients, melancholic patients presented with different demographic and clinical features, which have implications for treatment decisions

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Characteristics of carbonyls : concentrations and source strengths for indoor and outdoor residential microenvironments in China

Indoor and outdoor carbonyl concentrations were measured simultaneously in 12 urban dwellings in Beijing, Shanghai, Guangzhou, and Xi’an, China in summer (from July to September in 2004) and winter (from December 2004 to February 2005). Formaldehyde was the most abundant indoor carbonyls species, while formaldehyde, acetaldehyde and acetone were found to be the most abundant outdoor carbonyls species. The average formaldehyde concentrations in summer indoor air varied widely between cities, ranging from a low of 19.3 μg m−3 in Xi’an to a high of 92.8 μg m−3 in Beijing. The results showed that the dwellings with tobacco smoke, incense burning or poor ventilation had significantly higher indoor concentrations of certain carbonyls. It was noticed that although one half of the dwellings in this study installed with low emission building materials or furniture, the carbonyls levels were still significantly high. It was also noted that in winter both the indoor and outdoor acetone concentrations in two dwellings in Guangzhou were significantly high, which were mainly caused by the usage of acetone as industrial solvent in many paint manufacturing and other industries located around Guangzhou and relatively longer lifetime of acetone for removal by photolysis and OH reaction than other carbonyls species. The indoor carbonyls levels in Chinese dwellings were higher than that in dwellings in the other countries. The levels of indoor and ambient carbonyls showed great seasonal differences. Six carbonyls species were carried out the estimation of indoor source strengths. Formaldehyde had the largest indoor source strength, with an average of 5.25 mg h−1 in summer and 1.98 mg h−1 in winter, respectively. However, propionaldehyde, crotonaldehyde and benzaldehyde had the weakest indoor sources

Evaluation of modeling and measurement techniques of ultraviolet germicidal irradiation effectiveness: towards the design of immune buildings

While concerns about occupants\u27 health, comfort, energy consumption, and environment are becoming a main design consideration for ventilation systems there are also threats to public safety and security that cannot be overlooked and need to be taken into consideration. A sudden release of chemical and biological agents can pose a safety and security threat to public buildings and can cause injuries and loss of life. Recently air-cleaner technology has been introduced for air sterilization and purification in industrial buildings and hospitals due to its long life, functionality, and sustainability. However this technology has not been applied to the nonindustrial built environment in general, and the possibility of a sudden release of chemical or biological agents in particular has not been addressed. This paper presents a detailed review of previous studies on the measurement of ultraviolet germicidal irradiation effectiveness for decontamination, particularly as related to rooms and mechanical systems (ducting) in buildings. It also discusses the methods used to model the space, as well as the measurements and methods used to measure its performance followed by a comparison of the results and discussion of the possible causes of variance in reported data

Performance of mechanical filters and respirators for capturing nanoparticles: limitations and future direction

There is an increasing concern about the health hazard posed to workers exposed to inhalation of nanoparticles. Inhaling nanoparticles posses an occupational hazard due to elevated amount emitted to the atmosphere and working environment. Nanoparticles have potential toxic properties: the high particle surface area, number concentration, and surface reactivity. Inhalation, the most common route of nanoparticle exposure, has been shown to cause adverse effects on pulmonary functions and the deposited particles in the lung can be translocated to the blood system by passing through the pulmonary protection barriers. Filtration is the simplest and most common method of aerosol control. It is widely used in mechanical ventilation and respiratory protection. However, concerns have been raised regarding the effectiveness of the filters for capturing nanoparticles. This paper reviews the literature on the filtration performance of mechanical filters and respirators against nanoparticles. It includes the discussion about filtration mechanisms, theoretical models, affecting factors of the filtration efficiency, and testing protocols for respirator and filter certification

Investigation of potential affecting factors on performance of N95 respirator

With the exponential growth of the nano-technological products and their potential impact on the workers’ health and safety, the N95 filtering face-piece respirators (FFRs) are commonly recommended to protect them from the exposure to nano-particles in workplaces. This paper reports the outcomes of a series of experiments carried out to characterize the performance of NIOSH approved N95 filtering face-piece respirators against particles in nano-range: poly-dispersed and mono-dispersed sodium chloride (NaCl) particles were used in this study. In the first experimental set-up, a methodology was developed to test a N95 respirator model, sealed on a manikin head, against 15 to 200 nm poly-dispersed NaCl aerosols as function of flow rate (85, 135, 270 and 360 liters/min), loading time (up to 5 hours), and relative humidity (RH) (10, 30 and 70%). In the second phase, the experimental set-up was adapted to test N95 respirators against mono-dispersed particles (at twelve particle sizes) with a size range between 20 to 200 nm at a constant flow rate of 85 liters/min. The results from the poly-dispersed aerosol test (PAT) method indicated that the inhalation flow rate had a strong impact on the initial particle penetration; the maximum penetration level through the N95 respirator dramatically exceeded the 5% NIOSH certification criterion at flow rates higher than 85 liters/min. The particle penetrations at the Most Penetrating Particle Size (MPPS), occurring between 30 to 50 nm, were respectively 6.6, 11.7 and 15.3% for the airflow rate of 135, 270 and 360 liters/min. The outcomes of the effect of particle loading on the filter performance showed that, the particle penetration decreased through the N95 respirator for particle sizes below 100 nm. The mono-dispersed aerosol test (MAT) method was performed at 85 liters/min constant flow rate; the initial particle penetration at the MPPS was below 5% NIOSH certification criterion. Moreover, the initial particle penetration value, measured with (MAT) method was higher than the one measured with (PAT) method at each corresponding particle size

Characteristics of particle emissions from light duty diesel vehicle fueled with ultralow sulphur diesel and biodiesel blend

This study investigates the particle emissions from a diesel vehicle fueled with ultralow sulphur diesel (B0, ULSD) and 5 % biodiesel blend (B5) by a chassis dynamometer test under three driving conditions. Elemental carbon (EC), organic carbon (OC), 30 species of polycyclic aromatic hydrocarbon (PAH) and 10 species of oxygenated PAH (oxy-PAH) were analyzed to quantify the chemical compositions of the collected particulate matter (PM). The emission factors (EFs) of OC were increased with B5 by a range between 39.5 % and 113.7 %, compared with B0. Both fuel blends recorded a trace amount of EC (0.25 mg/kg or less). It was found that the B5 EFs of total PAHs were decreased by a range between 15.2 % and 50.2 % relative to B0. 2- to 3-ring species, the dominant PAHs and oxy-PAHs, were decreased substantially when using B5. However, the results showed that biodiesel blend promoted the emission of 4- and 5-ring oxy-PAHs and 5- to 7-ring PAHs. The application of B5 shifted the composition towards a higher proportion of PAHs with higher molecular weight and more oxy-PAHs. Due to the increased emissions in PAHs with higher toxic equivalent factors (TEFs), the application of B5 resulted in an increase in toxicity expressed in BAPeq range from 11.3 % to 117.0 %

An environmental chamber study of the characteristics of air pollutants released from environmental tobacco smoke

Environment tobacco smoke (ETS) is an important source of anthropogenic pollution in indoor environments. This research reports an environmental chamber study of pollutants released from ETS generated by smoking cigarettes in the chamber. Six cigarettes samples sold in Hong Kong and China were characterized. Gaseous pollutants: carbon monoxide (CO), sulphur dioxide (SO2), nitric oxide (NO), nitrogen dioxide (NO2), methane (CH4), non-methane hydrocarbon (NMHC), carbonyls and volatile organic compounds (VOCs); and particulate matter (PM), including organic carbon (OC), elemental carbon (EC) and total carbon (TC), were determined using online and offline analytical methods during smoking and post-smoking periods. Acetaldehyde, acetone and formaldehyde were the three most abundant carbonyls. A total of 18 aromatic and chlorinated VOCs were quantified. Among these, benzene and toluene were the two most abundant VOCs. OC was more dominant (\u3e 93% of TC) than EC. The amounts of tar and nicotine in the cigarettes could have a direct correlation with the PM emitted. Menthol, an additive in cigarettes, could also contribute to the ETS pollutants. The indoor ETS could be removed by a higher air exchange rate, which would also minimize secondary VOC formation