Impact of Urban 3D Morphology on Particulate Matter 2.5(PM2.5) Concentrations:Case Study of Beijing, China

Urban particulate matter 2.5(PM2.5)pollution and public health are closely related,and concerns regarding PM2.5 are widespread.Of the underlying factors,the urban morphology is the most manageable.Therefore,investigations of the impact of urban three-dimensional(3D)morphology on PM2.5 concentration have important scientific significance.In this paper,39 PM2.5 monitoring sites of Beijing in China were selected with PM2.5 automatic monitoring data that were collected in 2013.This data set was used to analyze the impacts of the meteorological condition and public transportation on PM2.5 concentrations.Based on the elimination of the meteorological conditions and public transportation factors,the relationships between urban 3D morphology and PM2.5 concentrations are highlighted.Ten urban 3D morphology indices were established to explore the spatial-temporal correlations between the indices and PM2.5 concentrations and analyze the impact of urban 3D morphology on the PM2.5 concentrations.Results demonstrated that road length density(RLD),road area density(RAD),construction area density(CAD),construction height density(CHD),construction volume density(CVD),construction otherness(CO),and vegetation area density(VAD)have positive impacts on the PM2.5 concentrations,whereas water area density(WAD),water fragmentation(WF),and vegetation fragmentation(VF)(except for the 500 m buffer)have negative impacts on the PM2.5 concentrations.Moreover,the correlations between the morphology indices and PM2.5 concentrations varied with the buffer scale.The findings could lay a foundation for the high-precision spatial-temporal modelling of PM2.5 concentrations and the scientific planning of urban 3D spaces by authorities responsible for controlling PM2.5 concentrations.

Characteristics and fate behavior of environmentally persistent free radicals in atmospheric particulate matter

Background,aim,and scope Environmentally persistent free radicals(EPFRs)have received significant attention due to their longer lifetime and stable existence in various environments.The strong environmental migration ability of particulate matter allows EPFRs to migrate over long-distance transport,thereby impacting the quality of the local atmospheric environment.Additionally,EPFRs can also adhere to atmospheric particles and interact with typical gaseous pollutants to affect atmospheric chemical reactions.EPFRs can produce some reactive organic species,promoting oxidative stress in the human body,damaging biological macromolecules and ultimately affecting the organism health.EPFRs are considered as a novel type of pollutant that affects human health.Despite their significance,there are few literatures available on the characteristics and fate behaviors of EPFRs up to date.Therefore,supplemental reviews are crucial for providing comprehensive understanding of EPFRs.Materials and methods This review summarizes the characteristics of EPFRs in particulate matter,outlines the generation mechanism and influencing factors of EPFRs,and the impacts of EPFRs on environmental quality and organism health.Results The content of EPFRs in particulate matter ranges from 1017 to 1020 spins∙g−1.Due to the strong mobility of atmospheric particulate matter,the long-term exposure to high levels of EPFRs may aggravate the impact of particulate matter on human health.The interaction between EPFRs and typical gaseous pollutants can alter their fate and influence atmospheric chemical reactions.EPFRs are mainly produced by transition metal elements and substituted aromatic hydrocarbons through electron transfer.Additionally,the chemical bond rupture of organic substances through heat treatment or ultraviolet radiation can also produce EPFRs,and heterogeneous reactions are capable producing them as well.The production of EPFRs is not only influenced by transition metal elements and precursors,but also by various environmental factors such as oxygen,temperature,light radiation,and relative humidity.Discussion EPFRs in atmospheric particulates matters are usually rich in fine particulates with obvious seasonal and regional variations.They can easily enter the human respiratory tract and lungs with inhalable particulates,thereby increasing the risk of exposure.Additionally,EPFRs in atmospheric particulates can interact with some typical gaseous pollutants,impacting the life and fate of EPFRs in the atmosphere,and alter atmospheric chemical reactions.Traditionally,EPFRs are generated by transition metal elements and substituted aromatic hydrocarbons undergoing electron transfer in the post-flame and cool-zone regions of combustion systems and other thermal processes to remove HCl,H_(2)O or CO groups,ultimately produce semiquinones,phenoxyls,and cyclopentadienyls.Recent studies have indicated that EPFRs can also be generated under the conditions of without transition metal elemental.Organics can also produce EPFRs through chemical bond rupture during heat treatment or light radiation conditions,as well as through some heterogeneous reactions and photochemical secondary generation of EPFRs.The presence or absence of oxygen has different effects on the type and yield of EPFRs.The concentration,type,and crystal type of transition metal elements will affect the type,content,and atmospheric lifetime of EPFRs.It is generally believed that the impact of transition metal element types on EPFRs is related to the oxidation-reduction potential.The combustion temperature or heat treatment process significantly affects the type and amount of EPFRs.Factors such as precursor loading content,pH conditions,light radiation and relative humidity also influence the generation of EPFRs.EPFRs can interact with pollutants in the environment during their migration and transformation process in environmental medium.This process accelerates the degradation of pollutants and plays a crucial role in the migration and transformation of organic pollutants in environmental media.The reaction process of EPFRs may lead to the production of reactive oxygen species(ROS)such as∙OH,which can induce oxidative stress,inflammation and immune response to biological lung cells and tissues,leading to chronic respiratory and cardiopulmonary dysfunction,cardiovascular damage and neurotoxic effects,ultimately impacting the health of organisms.Conclusions The interaction mechanism between EPFRs in particulate matter and gaseous pollutants remains unclear.Furthermore,research on the generation mechanism of EPFRs without the participation of transition metals is not comprehensive,and the detection of EPFRs is limited to simple qualitative categories and lack accurate qualitative analysis.Recommendations and perspectives Further research should be conducted on the generation mechanism,measurement techniques,migration pathways,and transformation process of EPFRs.It is also important to explore the interaction between EPFRs in atmospheric particulate matter and typical gaseous pollutants.

Spatial and Temporal Variation of Particulate Matter (PM10 and PM2.5) and Its Health Effects during the Haze Event in Malaysia

This study aims to assess and compare levels of particulate matter(PM10 and PM2.5)in urban and industrial areas in Malaysia during haze episodes,which typically occur in the south west monsoon season.The high concentrations of atmospheric particles are mainly due to pollution from neighbouring countries.Daily PM concentrations were analysed for urban and industrial areas including Alor Setar,Tasek,Shah Alam,Klang,Bandaraya Melaka,Larkin,Balok Baru,and Kuala Terengganu in 2018 and 2019.The analysis employed spatiotemporal to examine how PM levels were distributed.The data summary revealed that PM levels in all study areas were right-skewed,indicating the occurrence of high particulate events.Significant peaks in PM concentrations during haze events were consistently observed between June and October,encompassing the south west monsoon and inter-monsoon periods.The study on acute respiratory illnesses primarily focused on Selangor.Analysis revealed that Klang had the highest mean number of inpatient cases for acute exacerbation of bronchial asthma(AEBA)and acute exacerbation of chronic obstructive pulmonary disease(AECOPD)with values of 260.500 and 185.170,respectively.Similarly,for outpatient cases of AEBA and AECOPD,Klang had the highest average values of 41.67 and 14.00,respectively.Shah Alam and Sungai Buloh did not show a significant increase in cases during periods of biomass burning.The statistical analysis concluded that higher concentrations of PM were associated with increased hospital admissions,particularly from June to September,as shown in the bar diagram.Haze episodes were associated with more healthcare utilization due to haze-related respiratory illnesses,seen in higher inpatient and outpatient visits(p<0.05).However,seasonal variability had minimal impact on healthcare utilization.These findings offer a comprehensive assessment of PM levels during historic haze episodes,providing valuable insights for authorities to develop policies and guidelines for effective monitoring and mitigation of the negative impacts of haze events.

Exposure to ambient air particulate matter and non-alcoholic fatty liver disease

The present study was designed to alert the public opinion and policy makers on the supposed enhancing effects of exposure to ambient air particulate matter with aerodynamic diameters < 2.5 mm (PM 2.5 ) on non-alcoholic fatty liver disease (NAFLD), the most common chronic liver disease in Western countries. For far too long literature data have been fixated on pulmonary diseases and/or cardiovascular disease, as consequence of particulate exposure, ignoring the link between the explosion of obesity with related syndromes such as NAFLD and air pollution, the worst characteristics of nowadays civilization. In order to delineate a clear picture of this major health problem, further studies should investigate whether and at what extent cigarette smoking and exposure to ambient air PM 2.5 impact the natural history of patients with obesity-related NAFLD,i.e. , development of non alcoholic steatohepatitis, disease characterized by a worse prognosis due its progression towards fibrosis and hepatocarcinoma.

Effects of Lianhua Qingwen on Pulmonary Oxidative Lesions Induced by Fine Particulates(PM2.5) in Rats

Objective To investigate the antagonistic effects of different doses of Lianhua Qingwen on pulmonary injury induced by fine particulates PM2.5 in rats. Methods Fine particulates suspended in the environment were collected. Forty-eight healthy adult wistar rats were randomly divided into 6 groups with 8 rats in each group. Four groups of rats were exposed to PM2.5 by intratracheally dripping suspensions of fine particulates PM2.5(7.5 mg/kg) as dust-exposed model rats. Among them 24 rats in three groups received Lianhua Qingwen treatment(crude drug) at a dose of 2 g/kg, 4 g/kg, 8 g/kg per day for 3 days before dust exposure and were defined as low-dose, middle-dose and high-dose Lianhua Qingwen treatment groups respectively. The other dust-exposed model rats without treatment were assigned as PM2.5 control group. The un-exposed rats were set as saline control group(1.5 ml/kg saline) and blank control group. All rats were killed after 24 hours of the exposure. Lung tissue, serum and bronchoalveolar lavage fluid(BALF) were collected. The levels of malonaldehyde(MDA), lactate dehydrogenase(LDH), and glutathione peroxidase(GSH-PX) in blood serum and BALF, and superoxide dismutase(SOD) in blood surum were measured using fluorescent quantitation PCR; Expression of NF-E2-related factor 2(NRF-2), heme oxygenase 1(HO-1) and quinone oxidoreductase 1(NQO1) in lung tissues were measured using Western blot. Pathological changes of lung tissues in each group were also examined. Results Pathology revealed thickened alveolar septum, congestion of capillary, interstitial edema and infiltration of lymphocyte and neutrophil surrounding bronchiole in the PM2.5 control group, which weresignificantly relieved in the Lianhua Qingwen treatment groups. Compared to the blank and saline control groups, the PM2.5 control group had significantly higher levels of LDH and MDA(p<0.01) and lower level of GSH-PS(p<0.01) in BALF, significantly higher levels of LDH and MDA(p<0.05) and lower level of GSH-PS(p<0.05) in rat serum. The levels of MDA in blood serum and BALF were significantly lower in each treatment group than that in PM2.5 control group(all P<0.05). In both middle-dose and high-dose treatment group the measurements of LDH in serum and BALF as well as GSH-PX in serum were significant difference from those of PM2.5 control group(all P<0.05). Expressions of NRF-2, HO-1 and NQO1 in lung tissues were significantly different among middle-dose and high-dose treatment group compared with those in PM2.5 control group(all P<0.05). Conclusion Fine particulates PM2.5 in environment may induce pulmonary oxidative lesions in rats. Middle-dose and high-dose Lianhua Qingwen has antagonist effece on the injuries induced by fine particulates.

Ambient Fine Particulate Matter Exposure and Blood Pressure:Evidence from a Large Chinese Multiple Follow-Up Study

Objective This study aimed to investigate the association of ambient PM_(2.5)exposure with blood pressure(BP)at the population level in China.Methods A total of 14,080 participants who had at least two valid blood pressure records were selected from the China Health and Retirement Longitudinal Survey during 2011–2015.Their long-term PM_(2.5)exposure was assessed at the geographical level,on the basis of a regular 0.1°×0.1°grid over China.A mixed-effects regression model was used to assess associations.Results Each decrease of 10μg/m^(3)in the 1 year-mean PM_(2.5)concentration(FPM1Y)was associated with a decrease of 1.24[95%confidence interval(CI):0.84–1.64]mmHg systolic BP(SBP)and 0.50(95%CI:0.25–0.75)mmHg diastolic BP(DBP),respectively.A robust association was observed between the long-term decrease in PM_(2.5)and decreased BP in the middle-aged and older population.Using a generalized additive mixed model,we further found that SBP increased nonlinearly overall with FPM1Y but in an approximately linear range when the FPM1Y concentration was<70μg/m^(3);In contrast,DBP increased approximately linearly without a clear threshold.Conclusion Efficient control of PM_(2.5)air pollution may promote vascular health in China.Our study provides robust scientific support for making the related air pollution control policies.

Short-term exposure to fine particulate matter and hospital admission for stroke:a meta-analysis

Objective Air pollution is an important risk factor for cardiovascular diseases throughout the world.Fine particulate matter(PM)air pollution alone is responsible for over three million deaths each year.Large and growing literature has explored whether short-term exposure to fine particulate matter is associated with stroke,but results from prior studies have been inconsistent.To fill this gap,we assessed the evidence quantitatively from epidemiological time-series studies published worldwide and determined whether short-term exposure to fine particulate matter(<2.5μm or<10μm)diameter[PM2.5 and PM10]was associated with increased risk of hospital admission for stroke(including ischemic and hemorrhagic stroke).

Human Health Risks from Exposure to Heavy Metals of Suspended Particulate Matter around the Tongon Gold Mine, Côte d’Ivoire

The Tongon mine, the largest gold mine in C?te d’Ivoire, has been in operation since April 2010. However, to our knowledge to date, no study has been conducted on metallic contamination in suspended particulate matter (PM10 and PM2.5) where there is a lack of information on the carcinogenic and non-carcinogenic risk to human health associated with the exposure of populations in the Tongon area to these pollutants. The general objective of this study is to evaluate the level of contamination of PM10;PM2.5 by heavy metals and their impact on the health of populations exposed to these pollutants in the Tongon gold mine area. The sampling and measurement of suspended particulate matter (PM10 and PM2.5) were done using a MiniVol TAS passive air sampler. Heavy metal concentrations were determined by inductively coupled plasma mass spectroscopy (Nex ION 2000 ICP-MS, USA). The results indicate that the average concentrations of suspended particles (PM2.5 and PM10) obtained are all above the recommended exposure limits. In addition, among the heavy metals contained in the suspended particles, the concentrations of arsenic and nickel are high and all above the standard limit values. The assessment of the health risks related to the inhalation of PM10 particles reveals that their inhalation over a long period could cause a carcinogenic risk.

Effect of Varying Temperature and Oxygen on Particulate Matter Formation in Oxy-Biomass Combustion

Offsetting particulate matter emissions has become a critical global aim as there are concerted efforts to deal with environmental and energy poverty challenges.This study consists of investigations of computing emissions of particulate matter from biomass fuels in various atmospheres and temperatures.The laboratory setup included a fixed bed electric reactor and a particulate matter(PM)measuring machine interfaced with the flue gas from the fixed bed reactor combustion chamber.The experiments were conducted at seven different temperatures(600℃-1200℃)and six incremental oxygen concentrations(21%-100%).Five biomass types were studied;A-cornstalk,B-wood,C-wheat straw,D-Rice husk,E-Peanut shell,each pulverized to a size of approximately 75 microns.The study shows that PM emitted during char combustion is consistently higher than that emitted during the de-volatilization.During de-volatilization,increase in temperature leads to linear decrease in PM emission between atmospheres of 21%O_(2)to 50%O_(2),thereafter,between 70%O_(2)to 100%O_(2);increase in temperature leads to a rise in PM emission.The average PM formation from all the five considered biomass is relatively comparable however,with differing atmospheres and temperatures,the fibrous and low-density biomass forms more PM.During char combustion,the study shows that at oxygen levels of 21%,70%,90%and 100%,increase in temperature leads to increased PM emission.The increase in oxygen concentration and temperature increases the rate of combustion hence diminishing the time of combustion.

PM2.5对代谢相关脂肪性肝病模型小鼠肝淋巴生成的影响

目的研究大气细颗粒物(particulate matter 2.5,PM2.5)暴露对C57BL/6J小鼠和代谢相关脂肪性肝病模型小鼠肝淋巴生成的影响,为防治PM2.5暴露所致肝损伤提供新靶点。方法将40只雄性C57BL/6J小鼠随机分为正常组,PM2.5组,代谢相关脂肪性肝病模型组(MAFLD组)和PM2.5-MAFLD组。MAFLD组和PM2.5-MAFLD组小鼠连续12周给予高脂饲料,其余两组给予普通饲料。从13~16周,PM2.5组和PM2.5-MAFLD组小鼠通过气管滴注法进行PM2.5染毒(每周2次);其余两组小鼠同时通过气管滴注法滴注生理盐水。末次PM2.5染毒结束24 h后将实验动物处死。测定小鼠血清丙氨酸氨基转移酶(alanine aminotransferase,ALT)和天冬氨酸氨基转移酸(aspartate aminotransferase,AST)水平;用免疫荧光染色法评估肝淋巴LYVE1表达水平;测定肝氧化应激指标(4-HNE和T-GSH/GSSG)水平;用蛋白免疫印迹法测定肝淋巴生成标志蛋白(PROX1和LYVE1),淋巴生成调节蛋白VEGF-C和淋巴连接蛋白VE-cadherin的蛋白质表达水平。结果PM2.5染毒显著增加了MAFLD组小鼠血清AST和ALT水平,显著降低了肝组织PROX1、LYVE1和VEGF-C蛋白表达水平,增加肝4-HNE水平和降低了肝T-GSH/GSSG水平(P<0.05)。然而,PM2.5染毒并没有显著影响C57BL/6J小鼠血清AST和ALT水平、肝组织中PROX1、LYVE1、VEGF-C和VE-cadherin的蛋白表达水平及肝的4-HNE和T-GSH/GSSG(P>0.05)。结论PM2.5染毒能显著加重MAFLD小鼠肝的氧化损伤,并且能通过降低肝VEGF-C减少肝淋巴生成。

A Study of the Correlation between the Concentration of Particulate Matter and Green Area Ratio Measured through a Portable Monitoring System: With Particular Focus on the Case of Dalseo-Gu, Daegu Metropolitan City

This study analyzed the relationship between the measured concentration of particulate matter (PM) and green area, which is an important spatial factor affecting urban PM concentration and even more carbon neutral in cities. In order to investigate the effects of green area, the green area ratio (GAR) is used and correlated with particulate matter. As a result of analyzing the correlation between GAR and PM concentration using the measured PM data, it was found that there was a positive correlation between the two variables. Hence, the higher the GAR, the lower the PM concentration. It can be said that the introduction of spatial elements with high GAR scores, such as parks and forests in cities, is effective in reducing PM concentration. In this study, a portable PM monitoring system using a vehicle for PM measurement was also established and operated. As a result, it was found that a PM monitoring system using a light-scattering sensor is an effective PM measurement method that can be used at the local government level. It was also found that a follow-up study is needed in the future to identify the PM mitigation functions of urban green areas according to the detailed characteristics of green areas as well as various environmental factors. This study can be used in air quality improvement activities and efforts as reference data by policy decision makers and in the field of environmental planning associated with the removal of airborne particulate matter pollution in urban areas.

Indoor and Outdoor Particulate Matter Exposure of Rural Interior Alaska Residents

To assess the exposure of residents in rural communities in the Yukon Flats to particulate matter of 2.5 μm or less in diameter (PM2.5), both indoor and outdoor concentration observations were carried out from March to September 2019 in Ft. Yukon, Alaska. Indoor concentrations were measured at 0.61 m (breathing level during sleeping) in homes and at 1.52 m heights (breathing level of standing adult) in homes and office/commercial buildings. Air quality was better at both heights in cabins than frame homes both during times with and without surface-based inversions. In frame houses, concentrations were higher at 0.61 m than 1.52 m, while the opposite is true typically for cabins. Differences between shoulder season and summer indoor concentrations in residences were related to changes in heating, subsistence lifestyle and mosquito repellents. In summer, office and commercial buildings, air quality decreased due to increased indoor emissions related to increased use of equipment and mosquito pics as well as more merchandise. During summer indoor concentrations reached unhealthy for sensitive groups to hazardous conditions for extended times that even exceeded the high outdoor concentrations. Due to nearby wildfires, July mean outdoor concentrations were 55.3 μg·m-3 which exceeds the 24-h US National Ambient Air Quality Standard of 35 μg·m-3. Indoor and outdoor concentrations correlated the strongest with each other for office/commercial buildings, followed by frame houses and cabins. Office/commercial buildings with temperature monitors had one to two orders of magnitude lower concentrations than those without.

Using a Parafoil Kite for Measurement of Variations in Particulate Matter—A Kite-Based Dust Profiling Approach

This paper reports on the use of a kite-based system for measuring low-altitude particulate matter (PM) concentrations over grassland in Inner Mongolia. The motivation came from PM-concentration measurements at heights below 3 m over non-erodible surfaces which showed constant concentrations and made flux calculations relatively uncertain. One aim was the quantification of wind-driven matter fluxes across ecosystem boundaries, where the relevant layer can be assumed at heights below 100 m. Compared to other measurement techniques (e.g. LIDAR, towers and airborne systems) kite-based systems represent an inexpensive, highly flexible research tool which is well-suited for application in remote sites. The basis of the introduced system is a 4 m2 Parafoil kite which has enough lifting capacity to carry equipment of about 6 kg at wind velocities between 3 ms-1 to nearly 20 ms-1. A self-adjusting platform was constructed to balance moves and to carry a portable Environmental Dust Monitor (EDM), anemometer and a GPS receiver. So, all parameters necessary for a vertical profile of dust fluxes could be measured. In the first flights the applied kite-based dust profiling system (KIDS) was examined according to general technical application problems. Firstly, the influence of diverse surface characteristics, the flying condition and height-stability was tested. The result suggests that surface characteristics in general have a higher influence than the optimal wind velocity, which ranged from 9 ms-1 to 17 ms-1. Secondly, uncertainties in the measured data were quantified and assessed. The uncertainties in wind velocity measurements due to motion in horizontal and vertical direction were not higher than 0.45% - 0.65% and 1.8% - 2.2% during the kite ascent. The outcome of the study illustrates the suitable application of KIDS for low-altitude measurements in remote sites.

Antagonistic Effects of N-acetylcysteine on Mitogen-activated Protein Kinase Pathway Activation, Oxidative Stress and Inflammatory Responses in Rats with PM2.5 Induced Lung Injuries

Objective To evaluate the antagonistic effects of N-acetylcysteine(NAC)on mitogen-activated protein kinases(MAPK)pathway activation,oxidative stress and inflammatory responses in rats with lung injury induced by fine particulate matter(PM2.5).Methods Forty eight male Wistar rats were randomly divided into six groups:blank control group(C1),water drip control group(C2),PM2.5 exposed group(P),low-dose NAC treated and PM2.5 exposed group(L),middle-dose NAC treated and PM2.5 exposed group(M),and high-dose NAC treated and PM2.5 exposed group(H).PM2.5 suspension(7.5 mg/kg)was administered tracheally once a week for four times.NAC of 125 mg/kg,250 mg/kg and 500 mg/kg was delivered intragastrically to L,M and H group respectively by gavage(10 ml/kg)for six days before PM2.5 exposure.The histopathological changes and human mucin 5 subtype AC(MUC5AC)content in lung tissue of rats were evaluated.We investigated IL-6 in serum and bronchoalveolar lavage fluid(BALF)by Enzyme-linked immunosorbent assay(ELISA),MUC5AC in lung tissue homogenate by ELISA,glutathione peroxidase(GSH-PX)in serum and BALF by spectrophotometry,and the expression of p-ERK1/2,p-JNK1/2 and p-p38 proteins by Western blot.All the measurements were analyzed and compared statistically.Results Lung tissue of rats exposed to PM2.5 showed histological destruction and increased mucus secretion of bronchial epithelial cells.Rats receiving NAC treatment showed less histological destruction and mucus secretion.Of P,L,M and H group,MUC5AC in lung tissue,IL-6 in serum and BALF were higher than controls(C1 and C2)(all P<0.05),with the highest levels found in the P group and a decreasing trend with increase of NAC dose.The activity of GSH-PX in serum and BALF of PM2.5 exposed rats(P,L,M and H)was lower than that of controls(all P<0.05),with higher activities found in NAC treated rats(L,M,and H),and an increasing trend with increase of NAC dose.The expressions of p-ERK1/2,p-JNK1/2 and p-p38 proteins in PM2.5 exposed lung tissue(P,L,M and H)was higher than controls(all P<0.05),with decreased levels and dose dependent downregulation found in NAC treated rats.Conclusion NAC can antagonize major MAPK pathway activation,lung oxidative stress and inflammatory injury induced by PM2.5 in rats.

基于β射线法的新型PM2.5自动监测系统研究

近年来大颗粒物污染日趋严重,准确监测颗粒物PM2.5迫在眉睫。目前国外监测仪器已在国际上普遍使用,国内真正的知识产权产品比较少,产品的精度以及稳定性也有待提高。采用基于β射线法原理研制了PM2.5质量浓度在线监测系统,在仪器结构中提出采用原位检测的方法,并进行与标准称重法的比对实验来验证系统的可行性,结果表明两者测量数据的相关性为0.988。通过数据校正补偿后与监控站赛默飞仪器比对实时监测数据,日测量数据平均值相对偏差仅为1.8%。

燃煤锅炉PM2.5控制现状及改进建议

燃煤锅炉消耗大量煤炭,对大气环境中PM 2.5含量影响很大。对燃煤锅炉PM 2.5的治理是一个综合治理的过程,即包含一次可过滤颗粒物和一次可凝结颗粒物的治理,也包含对二次颗粒物前驱物SO2、NOx等的治理。本文从一次颗粒物和二次颗粒物治理角度,论述了燃煤锅炉PM 2.5的产生、控制现状,提出了PM 2.5控制技术的改进建议。

汽车尾气来源PM2.5颗粒物长期暴露导致SD雄鼠生殖功能损害

目的：建立Sprague Dawley（SD）大鼠空气细颗粒物（PM2.5）长期暴露模型,研究PM2.5长期暴露对SD大鼠生殖功能的损伤及其机制。方法：45只SD大鼠（80~94 g,28日龄）随机分配成3组：生理盐水对照组,低剂量组[2μg/（100 g·d）],高剂量组[16μg/（100 g·d）]。每天分别给予0.9%的生理盐水或PM2.5颗粒,连续暴露60 d,最后一次暴露24 h后各实验组选取10只与正常雌鼠合笼,统计雌鼠受孕率,剩余实验鼠取材,进行精子计数和畸形率测定、睾丸组织病理学检测以及睾丸组织Connexin43蛋白表达检测。结果：与对照组雌鼠受孕率（100%）相比,PM2.5暴露组正常雌鼠受孕率（高剂量组50%,低剂量组70%）明显降低,精子数量和质量明显下降,生精小管结构紊乱,管腔精子数减少,部分次级精母细胞脱落至管腔。睾丸组织中Connexin43蛋白表达下降,血睾屏障破坏。结论：汽车尾气来源PM2.5长期暴露影响SD大鼠生殖功能。

麦冬皂苷D预处理对PM2.5介导肺泡Ⅱ型上皮细胞炎性损伤的抑制作用及其机制

目的观察麦冬皂苷D预处理对大气细颗粒物(PM2.5)介导肺泡Ⅱ型上皮细胞MLE-12炎性损伤的抑制作用并探讨其机制。方法采用CCK-8法检测不同浓度麦冬皂苷D对MLE-12细胞活性的影响,结果显示麦冬皂苷D的安全用药范围为≤80μmol/L。取对数生长期的MLE-12细胞,随机分为空白对照组、PM2.5组及麦冬皂苷D组,麦冬皂苷D组分别加入浓度为10、20、40、80μmol/L的麦冬皂苷D预处理1 h,麦冬皂苷D组及PM2.5组中分别加入PM2.5混悬液(调整其终浓度为80μg/mL),作用24 h。空白对照组不作任何处理。采用ELISA法检测各组培养基上清炎性因子IL-1β、IL-6、IL-8、TNF-α表达,Western blotting法检测细胞核及细胞质NF-κB p65蛋白相对表达量。结果 PM2.5组培养基上清IL-1β、IL-6、IL-8、TNF-α表达均明显高于空白对照组(P均<0.01),加入80μmol/L麦冬皂苷D的麦冬皂苷D组培养基上清IL-1β、IL-6、IL-8、TNF-α表达均低于PM2.5组(P均<0.01)。加入不同浓度麦冬皂苷D的麦冬皂苷D组培养基上清IL-8、TNF-α表达均高于对照组,加入10、20、40μmol/L麦冬皂苷D的麦冬皂苷D组培养基上清IL-1β、IL-6表达均高于对照组(P<0.05或<0.01)。PM2.5组细胞核NF-κB p65蛋白相对表达量高于对照组,细胞质NF-κB p65蛋白相对表达量低于对照组(P均<0.01)。加入不同浓度麦冬皂苷D的麦冬皂苷D组细胞质NF-κB p65蛋白相对表达量均高于PM2.5组,加入20、40、80μmol/L麦冬皂苷D的麦冬皂苷D组细胞核NF-κB p65蛋白相对表达量均明显低于PM2.5组(P均<0.01)。结论麦冬皂苷D预处理可减轻PM2.5引起的MLE-12细胞炎性损伤,80μmol/L浓度时作用最明显且细胞毒性较小;其机制可能与抑制NF-κB p65入核及其相关信号通路激活有关。

高剂量PM2.5诱导卵清蛋白致哮喘小鼠肺损伤及其机制

目的研究不同剂量直径≤2.5μm的细颗粒物(PM2.5)诱导卵清蛋白(OVA)致哮喘小鼠肺损伤的程度。方法雄性BALB/c小鼠被随机分为正常对照组、OVA哮喘组、(1、5、15)mg/m L PM2.5处理的OVA哮喘组。收集支气管肺泡灌洗液(BALF)进行Gimsa染色观察白细胞数量,ELISA检测小鼠血清γ干扰素(IFN-γ)、白细胞介素17(IL-17)和IL-10的含量;实时定量PCR进行外周血单个核细胞(PBMC)Toll样受体4(TLR4)、核因子κB(NF-κB)的mRNA水平;Western blot法检测T细胞表达的T盒(T-bet)、维甲酸相关孤核受体γt(RORγt)和叉头盒P3(FOXP3)蛋白水平;HE染色观察小鼠肺组织病变情况。结果与对照组相比,OVA哮喘组小鼠的肺泡间隔增厚,肺泡腔增大,且出现较明显的炎性细胞浸润,BALF中与炎症反应相关的白细胞数目增多;与OVA哮喘组相比,15 mg/m L PM2.5诱导的哮喘小鼠上述变化极其明显。与对照组相比,OVA哮喘组小鼠血清中IFN-γ、IL-10显著降低,而IL-17显著增加;与OVA哮喘组相比,15 mg/m L PM2.5处理的OVA哮喘组IFN-γ、IL-10含量显著减少,而IL-17含量显著增加。与对照组相比,OVA哮喘组小鼠PBMC中TLR4、NF-κB表达量明显增加,与OVA哮喘组相比,15 mg/m L PM2.5处理OVA哮喘组TLR4、NF-κB表达量显著增加。与对照组相比,OVA哮喘组小鼠T-bet和FOXP3蛋白水平明显降低,RORγt蛋白水平明显升高;与OVA哮喘组相比,15 mg/m L PM2.5处理OVA哮喘组小鼠T-bet和FOXP3蛋白水平极显著降低,而RORγt蛋白水平显著增加。结论 15 mg/m L PM2.5通过激活TLR4/NF-κB信号通路促进OVA诱发的哮喘和肺损伤。

PM2.5对哮喘大鼠IL-17/IL-23炎症介质的影响及人参皂苷Rg1干预研究

目的:基于气道IL-17/IL-23炎症介质轴,探讨人参皂苷Rg1对PM2.5哮喘大鼠肺损伤保护机制。方法:采集并分离交通相关大气细颗粒物PM2.5,利用卵白蛋白致敏和激发建立幼龄哮喘大鼠模型,再给予PM2.5气管滴注建立PM2.5哮喘肺损伤模型,采用酶联免疫吸附试验(ELISA)法测定血清和肺泡灌洗液IL-17a、IL-6、IL-23、TGF-β_(1)含量,RT-PCR检测RORγt mRNA表达,并行肺组织病理和电镜分析。结果:成功建立PM2.5气管滴注哮喘大鼠模型;哮喘大鼠模型血清和肺泡灌洗液IL-17a、IL-6、IL-23、TGF-β_(1)表达量增大(P<0.01),肺组织RORγt mRNA表达量增加(P<0.01);经PM2.5气管滴注后,模型组大鼠血清和肺泡灌洗液IL-17a、IL-6、IL-23、TGF-β_(1)含量进一步增加,RORγt mRNA表达量进一步上升(P<0.01);经皂苷Rg1干预后,呈现剂量依赖性下调血清和肺泡灌洗液IL-17a、IL-6、IL-23、TGF-β_(1)水平,下调RORγt mRNA表达量。结论:人参皂苷Rg1呈剂量依赖性改善PM2.5致哮喘大鼠肺气道炎症反应、改善肺损伤。