Carbon monoxide and stroke: A time series study of ambient air pollution and emergency hospitalizations

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Air pollution and mortality: Effect modification by personal characteristics and specific cause of death in a case-only study

Short-term effects of air pollution on mortality have been well documented in the literature worldwide. Less is known about which subpopulations are more vulnerable to air pollution. We conducted a case-only study in Hong Kong to examine the potential effect modification by personal characteristics and specific causes of death. Individual information of 402,184 deaths of non-external causes and daily mean concentrations of air pollution were collected from 2001 to 2011. For a 10 μg/m3 increase of pollution concentration, people aged ≥∇65 years (compared with younger ages) had a 0.9–1.8% additional increase in mortality related to PM, NO2, and SO2. People dying from cardiorespiratory diseases (compared with other non-external causes) had a 1.6–2.3% additional increase in PM and NO2 related mortality. Other subgroups that were particularly susceptible were females and those economically inactive. Lower socioeconomic status and causes of cardiorespiratory diseases would increase the likelihood of death associated with air pollution.postprin

Who is more vulnerable to death from extremely cold temperatures? A case-only approach in Hong Kong with a temperate climate

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Dicarboxylic acids, ketocarboxylic acids, α-dicarbonyls, fatty acids and benzoic acid in PM2.5 aerosol collected during CAREBeijing-2007: an effect of traffic restriction on air quality

Thirty water-soluble organic species, including dicarboxylic acids, ketocarboxylic acids, α-dicarbonyls, fatty acids and benzoic acid were determined as well as organic carbon (OC), elemental carbon (EC) and water-soluble organic carbon (WSOC) in PM2.5 samples collected during the Campaign of Air Quality Research in Beijing 2007 (CAREBeijing-2007) in the urban and suburban areas of Beijing. The objective of this study is to identify the influence of traffic emissions and regional transport to the atmosphere in Beijing during summer. PM2.5 samples collected with or without traffic restriction in Beijing are selected to evaluate the effectiveness of local traffic restriction measures on air pollution reduction. The average concentrations of the total quantified bifunctional organic compounds (TQBOCs), total fatty acids and benzoic acid during the entire sampling period were 1184±241, 597±159 and 1496±511 ng m−3 in Peking University (PKU), and 1050±303, 475±114 and 1278±372 ng m−3 in Yufa, Beijing. Oxalic acid (C2) was found as the most abundant dicarboxylic acid at PKU and Yufa followed by phthalic acid (Ph). A strong even carbon number predominance with the highest level at stearic acid (C18:0), followed by palmitic acid (C16:0) was found for fatty acids. According to the back trajectories modeling results, the air masses were found to originate mainly from the northeast, passing over the southeast or south of Beijing (heavily populated, urbanized and industrialized areas), during heavier pollution events, whereas they are mainly from the north or northwest sector (mountain areas without serious anthropogenic pollution sources) during less pollution events. The data with wind only from the same sector (minimizing the difference from regional contribution) but with and without traffic restriction in Beijing were analyzed to evaluate the effectiveness of local traffic restriction measures on the reduction of local air pollution in Beijing. The results suggested that the traffic restriction measures can reduce the air pollutants, but the decrease of pollutants is generally smaller in Yufa compared to that in PKU. Moreover, an enhancement of EC value indicates more elevated primary emissions in Yufa during restriction periods than in non-restriction periods. This study demonstrates that even when primary exhaust was controlled by traffic restriction, the contribution of secondary organic species formed from photochemical processes was critical with long-range atmospheric transport of pollutants.published_or_final_versio

Nano-Engineered Environment for Nerve Regeneration: Scaffolds, Functional Molecules and Stem Cells

One of the most complex systems in the human body is the nervous system, which is divided into the central and peripheral nervous systems. The regeneration of the CNS is a complex and challenging biological phenomenon hindered by the low regenerative capacity of neurons and the prohibition factors in response to nerve injuries. To date, no effective approach can achieve complete recovery and fully restore the functions of the nervous system once it has been damaged. Developments in neuroscience have identified properties of the local environment with a critical role in nerve regeneration. Advances in biomaterials and biomedical engineering have explored new approaches of constructing permissive environments for nerve regeneration, thereby enabling optimism with regard to nerve-injury treatment. This article reviews recent progress in nanoengineered environments for aiding nerve-injury repair and regeneration, including nanofibrous scaffolds, functional molecules, and stem cells.postprin

Nano-Engineered Environment for Nerve Regeneration: Scaffolds, Functional Molecules and Stem Cells

One of the most complex systems in the human body is the nervous system, which is divided into the central and peripheral nervous systems. The regeneration of the CNS is a complex and challenging biological phenomenon hindered by the low regenerative capacity of neurons and the prohibition factors in response to nerve injuries. To date, no effective approach can achieve complete recovery and fully restore the functions of the nervous system once it has been damaged. Developments in neuroscience have identified properties of the local environment with a critical role in nerve regeneration. Advances in biomaterials and biomedical engineering have explored new approaches of constructing permissive environments for nerve regeneration, thereby enabling optimism with regard to nerve-injury treatment. This article reviews recent progress in nanoengineered environments for aiding nerve-injury repair and regeneration, including nanofibrous scaffolds, functional molecules, and stem cells.postprin

Ambient carbon monoxide and the risk of hospitalization due to chronic obstructive pulmonary disease

Data from recent experimental and clinical studies have indicated that lower concentrations of inhaled carbon monoxide might have beneficial antiinflammatory effects. Inhaled carbon monoxide has the potential to be a therapeutic agent for chronic obstructive pulmonary diseases (COPD). However, population-based epidemiologic studies of environmentally relevant carbon monoxide exposure have generated mixed findings. We conducted a time-series study in Hong Kong to estimate the association of short-term exposure to ambient carbon monoxide with emergency hospitalizations for COPD. We collected daily emergency hospital admission data and air pollution data from January 2001 to December 2007. We used log-linear Poisson models to estimate the associations between daily hospital admissions for COPD and the average daily concentrations of carbon monoxide while controlling for the traffic-related copollutants nitrogen dioxide and particulate matter with an aerodynamic diameter less than 2.5 μm. Results showed that ambient carbon monoxide was negatively associated with the risk of hospitalizations for COPD. After adjustment for levels nitrogen dioxide or particulate matter with an aerodynamic diameter less than 2.5 μm, the negative associations of carbon monoxide with COPD hospitalizations became stronger. The risk estimates were similar for female and male subjects. In conclusion, short-term exposure to ambient carbon monoxide was associated with a decreased risk of hospitalization for COPD, which suggests that carbon monoxide exposure provides some acute protection of against exacerbation of COPD.postprin

Heterogeneity of passenger exposure to air pollutants in public transport microenvironments

Epidemiologic studies have linked human exposure to pollutants with adverse health effects. Passenger exposure in public transport systems contributes an important fraction of daily burden of air pollutants. While there is extensive literature reporting the concentrations of pollutants in public transport systems in different cities, there are few studies systematically addressing the heterogeneity of passenger exposure in different transit microenvironments, in cabins of different transit vehicles and in areas with different characteristics. The present study investigated PM2.5 (particulate matter with aerodynamic diameters smaller than 2.5μm), black carbon (BC), ultrafine particles (UFP) and carbon monoxide (CO) pollutant concentrations in various public road transport systems in highly urbanized city of Hong Kong. Using a trolley case housing numerous portable air monitors, we conducted a total of 119 trips during the campaign. Transit microenvironments, classified as 1). busy and secondary roadside bus stops; 2). open and enclosed termini; 3). above- and under-ground Motor Rail Transport (MTR) platforms, were investigated and compared to identify the factors that may affect passenger exposures. The pollutants inside bus and MTR cabins were also investigated together with a comparison of time integrated exposure between the transit modes. Busy roadside and enclosed termini demonstrated the highest average particle concentrations while the lowest was found on the MTR platforms. Traffic-related pollutants BC, UFP and CO showed larger variations than PM2.5 across different microenvironments and areas confirming their heterogeneity in urban environments. In-cabin pollutant concentrations showed distinct patterns with BC and UFP high in diesel bus cabins and CO high in LPG bus cabins, suggesting possible self-pollution issues and/or penetration of on-road pollutants inside cabins during bus transit. The total passenger exposure along selected routes, showed bus trips had the potential for higher integrated passenger exposure compared to MTR trips. The present study may provide useful information to better characterize the distribution of passenger exposure pattern in health assessment studies and the results also highlight the need to formulate exposure reduction based air policies in large cities. © 2015 Elsevier Ltd.postprin