Constituents Of PM2 Research Articles

Characterization of atmospheric PM2.5 sources at a Central European urban background site

For the purposes of this work, a first in Poland, full-year collection of daily PM2.5 (particulate matter with aerodynamic diameter smaller than 2.5 μm) samples was chemically analyzed to determine the contents of elemental and organic carbon, water-soluble inorganic ions and 21 minor and trace elements in PM in an urban background site in Warsaw. Annual mean PM2.5 concentration reached 18.8 μg/m3, with the lowest levels in summer (11.5 μg/m3 on average) and the highest in winter (27.5 μg/m3), with several episodes reaching over 80 μg/m3. Strong seasonal differences were observed mainly for the contents of nitrate and secondary organic carbon (SOC), while sulphate showed the least variability. Secondary species constituted on average 45% of PM2.5 mass, suggesting large influence of regional and long-range transport of pollutants. Source apportionment with the use of positive matrix factorization (PMF) method, supported by the analysis of enrichment factors, led to identification of six main sources of PM2.5 origin: residential combustion (fresh & aged aerosol) (46% of PM2.5 mass), traffic exhaust (21%) and non-exhaust (10%) emissions, mineral dust/construction works (12%), high-temperature processes (8%) and steel processing (3%). Including primary organic carbon (POC) and SOC as two separate constituents helped to distinguish between the primary and secondary sources of the aerosol. The identification of sources was also supported by investigating their yearly and weekly profiles, as well as the correlation of PM constituents with meteorological conditions, which are one of the main drivers of heat generation activities. We found that the most distinctive markers of PM sources in Warsaw are SOC, Cl− and As for residential combustion, NH4+, Sb and POC for road transport, Ca and Mg for construction works and SO42− for long-range transport of PM.

Impacts of New Particle Formation on Short-term Meteorology and Air Quality as Determined by the NPF-explicit WRF-Chem in the Midwestern United States

ABSTRACT New particle formation (NPF) from nucleation and subsequent nuclei growth, which is frequently observed in the troposphere, is critical to aerosol-cloud interactions yet difficult to simulate. In this work, regional simulations with the fully coupled NPF-explicit WRF-Chem model link NPF to cloud properties and to changes in both meteorology and air quality in the U.S. Midwest during summer 2008. Simulations that include NPF have higher concentrations of condensation nuclei, as anticipated from the particle production associated with nucleation, leading to enhanced concentrations of cloud condensation nuclei (CCN) at high supersaturations. However, the online-coupled model develops a number of unexpected features that can be traced to a feedback loop involving aqueous (in-cloud) oxidation of sulfur combined with boundary layer NPF. Simulations with NPF (relative to simulations without) exhibit reduced PM2.5 sulfate mass, cloud dimming (reductions in the cloud frequency, CCN concentration at a low supersaturation, cloud optical depth, and cloud droplet number concentration), and enhanced surface-reaching shortwave radiation. This effect of NPF on the PM2.5 mass is mostly absent for other constituents of PM2.5. The implications of this feedback loop, which is not considered in most climate and air quality modeling, are discussed.

High level of source-specific particulate matter air pollution associated with cardiac arrhythmias

Epidemiological evidence linking source-specific ambient particulate matter with aerodynamic diameter <2.5 μm (PM2.5) and cardiac arrhythmias is limited. In this study, we investigated the impact of source-specific PM2.5 on cardiac arrhythmias in a panel of forty-five healthy adults living in Beijing, China, between 2015 and 2016. Repeated measures of 24-hour electrocardiograms were conducted during clinical visits, and daily counts of four arrhythmia events including supraventricular premature beat (SVPB), atrial tachycardia (AT), premature ventricular contraction (PVC) and ventricular tachycardia (VT) were recorded. One hundred forty-seven constituents in PM2.5 were analyzed for collected particulate samples, in which fifty-six of them above laboratory detection limits were selected for source apportionment analysis using positive matrix factorization. The average contributions of identified five major sources to PM2.5 were 45.9% from secondary nitrate/sulfate, 18.0% from coal combustion, 16.9% from crustal soil, 13.8% from biomass burning, and 5.4% from cooking. Generalized estimating equation models were used to estimate relative risks (RR) of arrhythmias in association with interquartile-range (IQR) increases in PM2.5 constituents and specific sources. Total PM2.5 mass as well as several combustion related constituents were found of significant impacts on increased risks of arrhythmia events. Among the identified sources of PM2.5, coal burning has been found the major source that associated with increased risks of SVPB, PVC and VT with RR of 1.19 [95% confidence intervals (CI): 1.04, 1.36] to 1.64 (95% CI: 1.35, 2.00). PM2.5 from combustion related secondary nitrate/sulfate was also found of significant impact on SVPB and AT, followed by PM2.5 from biomass burning and crustal soil. Our results indicated that PM2.5 from anthropogenic activity related sources were most responsible for increased risks of arrhythmia events. Our findings enhance the understanding of increased risks of arrhythmias from exposure to PM2.5, and provide evidence on source-specific PM control priorities.

Personal Exposure to PM2.5 and Its Bioreactivity in Healthy Adults of Hong Kong

Background: Mechanisms involving systemic inflammation have been proposed to explain the associations between PM2.5 with cardiopulmonary morbidity and mortality. Experimental evidence suggests that organic constituents in PM2.5 have critical health impact. However, there are limited studies related to the bioreactivity of personal PM2.5 in vitro with toxic components. Methods: Personal monitoring from 58 (aged 18-42 years) healthy adults during the summer and winter were conducted in Hong Kong. Personal exposures to PM2.5 as well as its chemical components including organic carbon, elemental carbon, polycyclic aromatic hydrocarbons (PAHs), and phthalates in personal samples were determined. Additionally, the bioreactivity of personal PM2.5 in vitro were evaluated. Cell variability, 8-isoprostane, lactate dehydrogenase (LDH), and interleukin-6 (IL-6) released were used to determined the PM bioreactiviy. Using the mixed-effects model, the relationships of bioreactivity to personal exposure to PM2.5 components were examined. Results: Winter exposures were 1.6-2.0 times greater than summer exposures for personal PM2.5, EC, PAHs, and phthalate. Personal exposure to OC was significantly correlated with LDH (p &amp;lt; 0.05) and IL-6 (p &amp;lt; 0.01). Moderate correlations (rs &amp;#61; 0.58, p &amp;lt; 0.05) were observed between OC and EC, but no correlations were observed between EC with bioreactivity of PM2.5. Conclusion: In vitro methods have an important role in the screening of bioreactivity of PM2.5. Results suggest exposure to PM2.5 components can induce cytotoxicity and system inflammation in healthy adults.

Additional Benefits of Federal Air-Quality Rules: Model Estimates of Controllable Biogenic Secondary Organic Aerosol.

Atmospheric models that accurately describe the fate and transport of trace species for the right reasons aid in the development of effective air-quality management strategies that safeguard human health. Controllable emissions facilitate the formation of biogenic secondary organic aerosol (BSOA) to enhance the atmospheric fine particulate matter (PM2.5) burden. Previous modeling with the EPA's Community Multiscale Air Quality (CMAQ) model predicted that anthropogenic primary organic aerosol (POA) emissions had the greatest impact on BSOA. That experiment included formation processes involving semivolatile partitioning but not aerosol liquid water (ALW), a ubiquitous PM constituent. We conduct 17 summertime CMAQ simulations with updated chemistry and evaluate changes in BSOA due to the removal of individual pollutants and source sectors for the contiguous U.S. CMAQ predicts SO2 from electricity generating units, and mobile source NOX emissions have the largest impacts on BSOA. The removal of anthropogenic NOX, SO2, and POA emissions during the simulation reduces the nationally averaged BSOA by 23, 14, and 8% and PM2.5 by 9.2, 14, and 5.3%, respectively. ALW mass concentrations decrease by 10 and 35% in response to the removal of NOX and SO2 emissions. This work contributes chemical insight into ancillary benefits of Federal NOX and SO2 rules that concurrently reduce organic PM2.5 mass.

Studies on constituents of Polygonum multiflorum extract in vivo and in vitro based on UPLC-Q-TOF-MS

To explore the drug-induced constituents in vivo of Polygonum multiflorum extract (PM). This study was the first to study the drug-induced constituents in target organ liver. Agilent MassHunter qualitative analysis software and Metabolite ID software were applied for the analysis of retention time, exact relative molecular mass, primary and secondary mass spectrum information based on ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) and targeted-MS/MS. By comparison with literature and standards, a total of 5 prototypes and 6 metabolites were identified or tentatively elucidated from the liver samples. In addition, the drug-induced constituents in plasma and PM were also analyzed in this study and 8 prototypes and 19 metabolites were detected from the plasma samples, while 30 compounds were detected from the extract of PM. Emodin oxidative acetylation metabolites, hydroxyl methylation metabolites, carboxylation glucuronidation metabolites and ketone glucuronidation metabolites in this study were first reported. Through the comparative analysis between the in vivo and in vitro constituents of PM, the study preliminarily revealed the drug-induced constituents (prototypes and metabolites) in liver and clarified the transfer process and transmutation rules of constituents in PM, blood and liver, which would further deepen our understanding on constituents of PM in vivo.

Interactions of Climate Change, Air Pollution, and Human Health.

I review literature on the impacts of climate change on air quality and human health, with a focus on articles published from 2013 on ozone and airborne particles. Selected previous literature is discussed where relevant in tracing the origins of our current knowledge. Climate and weather have strong influences on the spatial and temporal distribution of air pollution concentrations. Emissions of ozone and PM2.5 precursors increase at higher ambient temperatures. The reactions that form ozone occur faster with greater sunlight and higher temperatures. Weather systems influence the movement and dispersion of air pollutants in the atmosphere through the action of winds, vertical mixing, and precipitation, all of which are likely to alter in a changing climate. Recent studies indicate that, holding anthropogenic air pollution emissions constant, ozone concentrations in populated regions will tend to increase in future climate scenarios. For the USA, the climate impact on ozone is most consistently seen in north-central and north-eastern states, with the potential for many thousands of additional ozone-related deaths. The sensitivity of anthropogenic PM2.5 to climate is more variable across studies and regions, owing to the varied nature of PM constituents, as well as to less complete characterization of PM reaction chemistry in available atmospheric models. However, PM emitted by wildland fires is likely to become an increasing health risk in many parts of the world as climate continues to change. The complex interactions between climate change and air quality imply that future policies to mitigate these twin challenges will benefit from greater coordination. Assessing the health implications of alternative policy approaches towards climate and pollution mitigation will be a critical area of future work.

Epidemiological study of PM2.5 and risk of COPD-related hospital visits in association with particle constituents in Chuncheon, Korea.

Background and objectiveAside from smoking, which is already recognized as a strong risk factor for COPD, interest in the impact of particulate matter (PM) on COPD is increasing. This study aimed to investigate the effect of PM, especially with an aerodynamic diameter ≤2.5 µm (PM2.5), and its chemical constituents on the exacerbation of COPD.MethodsData on hospital visits including admission and outpatient clinic visits for exacerbation of COPD in Chuncheon, Korea, between 2006 and 2012 were extracted from the National Health Insurance Service database. PM2.5 and its chemical constituents were measured on the roof of the four-story Kangwon National University Natural Sciences building once every 3 days. Meteorological data were provided by the Korean Meteorological Administration.ResultsDuring the study period, the mean level of PM2.5 was 35.0±25.2 µg/m3, and the number of daily hospital visits were 6.42±4.28 and 2.07±1.93 for males and females, respectively. The number of COPD-related hospital visits increased with increasing PM2.5 after adjusting for meteorological covariates and females tended to be more affected sooner than males. Among the PM2.5 constituents, Al, Si, and elemental carbon were associated with increased hospital visits and there was a difference according to sex. In males, some constituents of PM2.5 were related to an increased risk of a hospital visit, mainly on the first and second days of measurement (Lag1 and Lag2). In contrast, there was no significant increase in the risk of hospital visits due to any of the PM2.5 constituents in females.ConclusionConcentrations of PM2.5 mass and some of the PM2.5 constituents were associated with increased COPD-related hospital visits in Chuncheon.

Fine particulate matter constituents and blood pressure in patients with chronic obstructive pulmonary disease: A panel study in Shanghai, China

ObjectiveThe evidence is limited about the potentially different health effects of various chemical constituents of fine particulate matter (PM2.5). We thus assessed the acute effects of various chemical constituents of PM2.5 on blood pressure (BP). MethodsWe performed a longitudinal panel study with six repeated visits in 28 urban residents with chronic obstructive pulmonary disease in Shanghai, China from May to July, 2014. Twelve (43%) of them took antihypertensive medications. We measured resting BP by using a mercury sphygmomanometer and monitored real-time concentrations of PM2.5 constituents at a nearby site. Based on the linear mixed-effects model, we evaluated the effects of 10 major constituents in PM2.5 on BP, using a single-constituent model and a constituent-residual model after accounting for the multicollinearity. ResultsWe obtained a total of 168 pairs of effective BP measurements during the study period. There are moderate or high correlations among various PM2.5 constituents. An interquartile range increase of PM2.5 (19.1μg/m3) was associated with increments of 1.90mmHg [95% confidence interval (CI): 0.66, 3.13] in systolic BP, 0.68mmHg (95%CI: −0.02, 1.37) in diastolic BP and 1.23mmHg (95%CI: 0.19, 2.29) in pulse pressure. Some constituents of PM2.5, including organic carbon, elemental carbon, nitrate and ammonium, were robustly associated with elevated BP after controlling for total PM2.5 mass and accounting for multi-collinearity. Two constituents (magnesium and calcium) were associated with decreased BP. ConclusionsOrganic carbon, elemental carbon, nitrate and ammonium may be mainly responsible for elevated BP from a short-term exposure to PM2.5.

Oxidative potential of PM10 and PM2.5 collected at high air pollution site related to chemical composition: Krakow case study

Measurements of the oxidative potential (OP) of airborne particulate matter may be applied for the assessment of the health-based exposure by integrating various biologically relevant properties of particles. This study aimed at the determination of oxidative activity of two size fractions of particulate using the ascorbic acid (AA) and reduced glutathione (GSH) assay. Samples of PM were collected in Krakow, one of the most polluted cities in Poland, in the city centre. Samples were collected during wintertime, when heating sources used in residential areas have significant influence on the concentrations of particulate matter in the air. PM10 and PM2.5 concentrations varied from 8.9 to 92.5 μg m−3. Samples were chemically analysed for elemental carbon, organic carbon, ions and metals. PM2.5 was found as a more oxidative active fraction, where OPAA and OPGSH depletions were up to 81.7 and 132.0 μg m−3, respectively. The average values of OPAA of PM10 and PM2.5 were similar and equalled 40.8 and 37.2 μg m−3, respectively. The average value of OPGSH of PM2.5 equalled 56.7 μg m−3 and was 3.5 times higher than OPGSH of PM10. The loss of AA amount in PM10 and PM2.5 and the depletion of GSH in PM2.5 were best described by the pseudo second-order kinetics model. The kinetics of the GSH depletion reaction in PM10 was best described by the pseudo first-order kinetics model. The strong correlations between carbonaceous and metallic constituents of PM and oxidative potential suggest their relevance in participation in oxidative activity of particulate matter.

The Acute Effects of Fine Particulate Matter Constituents on Blood Inflammation and Coagulation.

Limited evidence is available on the effects of various fine particulate matter (PM2.5) constituents on blood inflammation and coagulation. We examined the associations between 10 constituents and 10 circulating biomarkers in a panel of 28 urban residents with four repeated measurements in Shanghai, China. Based on the linear mixed-effect models, we fitted the single-constituent models, the constituent-PM2.5 joint models, and the constituent-residual models to evaluate the associations between PM2.5 constituents and eight inflammatory biomarkers (fibrinogen, C-reactive protein, monocyte chemoattractant protein-1, tumor necrosis factor-α, interleukin-1b, intercellular adhesion molecule-1, P-selectin, vascular cell adhesion molecule-1) and two coagulation biomarkers (plasminogen activator inhibitor-1 and soluble CD40 ligand). We found robust associations of organic carbon (OC), elemental carbon (EC), nitrate (NO3-), and ammonium (NH4+) with at least 1 of 8 inflammatory markers. On average, an interquartile range increase in the four constituents corresponded to increments of 50%, 37%, 25%, and 26% in inflammatory biomarkers, respectively. Only sulfate (SO42-) or NH4+ was robustly associated with coagulation markers (corresponding increments: 23% and 20%). Our results provided evidence that some constituents in PM2.5 (OC, EC, NO3-, SO42-, and NH4+) might play crucial roles in inducing systematic inflammation and coagulation, but their roles varied by the selected biomarkers.

Measurements of TSP, PM10, PM2.5, BC, and PM chemical composition from an urban residential location in Nepal

Particulate matter (PM2.5, PM10, and TSP), black carbon (BC), and PM constituent components were measured at a location in an urban residential neighborhood of Kathmandu Valley, Nepal. PM2.5, TSP, and BC were measured during winter, and PM2.5, PM10, and their chemical composition was measured during the summer monsoon periods in 2014. Both indoor and outdoor measurements were collected during the winter season. There was a distinct seasonal profile of PM2.5 concentration, with the 24-hour mean larger during winter (76 ± 18 μg/m3) than monsoon (21 ± 8 μg/m3). This site was located approximately 15 m above the street, but was still influenced by roadway combustion sources indicated by large BC concentration (15 ± 3 μgC/m3 during winter) and large rush hour PM and BC peaks. Two rush hour peaks of PM and BC were observed during morning and evening. Indoor and outdoor PM2.5 and BC concentration measured during winter were similar suggesting the heavy influence of outdoor traffic activities on such indoor environments. Mean 24-hour TSP during winter and PM10 during monsoon was 109 μg/m3 and 34 μg/m3, respectively. PM2.5 accounted for 75% of TSP during winter and 61% of PM10 during monsoon indicating a high degree of influence by PM2.5 sources. Sulfate, ammonium, and calcium were the dominant components of water-soluble ions, and silica, iron, aluminum, and barium were the major elements in both PM10 and PM2.5 during monsoon indicating the most important emission sources as traffic emissions and road/soil/construction-related dust.

Relationships of surface ozone with its precursors, particulate matter and meteorology over Delhi

The paper presents the temporal variations of surface ozone (O3) and its precursors (oxides of nitrogen (NOX), carbon monoxide (CO), methane (CH4) and non-methane hydrocarbons (NMHCs)) along with particulate matter (PM10 and PM2.5) and their relationship with meteorology during January 2012 to December 2014 at an urban site of Delhi, India. The mean mixing ratio of surface O3, NOX, CO, CH4 and NMHCs were 29.5 ± 7.3 ppb, 34.7 ± 11.2 ppb, 1.82 ± 0.52 ppm, 3.07 ± 0.37 ppm and 0.53 ± 0.17 ppm, respectively. This study also comprises an analysis of the relation between UV irradiance and surface O3. A relationship between the total oxidant concentrations (OX) and NOX has been used to identify the regional background O3 values and the local levels of primary pollution. An attempt has been made to identify the existence of NOX or NMHC sensitive regime by charting out relationships between O3, NOX and NMHCs. The respective high pollution periods of surface O3 and PM differ on a seasonal timescale. Linear regression analysis has been used to quantify the negative influence of the chemical constituents of PM (elemental carbon, NO3 −, SO4 2−) on O3 values. Statistical validation using bivariate correlation analysis, multiple linear regression (MLR) analysis and principal component analysis (PCA) strongly describes the intricate relationships among the aforesaid variables and meteorology. Potential Source Contribution Function (PSCF) and Concentration Weighted Trajectory (CWT) analysis indicated upper Indo-Gangetic Plain (IGP) as a significant source region of O3 precursor gases contributing for O3 values at the study site.

Mortality and Emergency room visits Associated with Particulate Matter Constituents in Metropolitan Taipei

OBJECTIVE: To evaluate the short-term effects of daily concentrations of PM10, PM2.5, and constituents on mortality of elder population and emergency room visits (ERV) of all ages population in Taipei, Taiwan. METHODS: This study uses a distributed lag non-linear model with Poisson distribution to estimate the cumulative 6-day (lags 0–5) relative risks (RRs) and confidence intervals (CIs) of mortality from and ERV of all causes, circulatory diseases, and respiratory diseases associated with daily concentrations of PM10, PM2.5, as well as constituents (organic carbon (OC), elemental carbon (EC), nitrate, and sulfate). RESULTS: Emergency room visits were more associated with concentrations of PM and its constituent, and the risk estimates were similar for PM10 and PM2.5. An increase in PM2.5 from 5 μg/m3 to 30 μg/m3 was associated with increased ERV risk of all causes and respiratory diseases with cumulative 6-day RR of 1.12 (95% CI: 1.06, 1.18) and 1.27 (95% CI: 1.10, 1.46), respectively. All-cause mortality significantly associated with concentrations of nitrate (RR=1.12 (95% CI: 1.02, 1.23) at 1 μg/m3), and mortality from circulatory diseases significantly associated with concentrations of sulfate (RR=1.31 (95% CI: 1.12, 1.54) at 7 μg/m3). All-cause ERV significantly associated with concentrations of OC (RR=1.03 (95% CI: 1.00, 1.06) at 1 μg/m3), EC (RR=1.08 (95% CI: 1.05, 1.12) at 2 μg/m3), nitrate higher than 6 μg/m3, and sulfate higher than 20 μg/m3. Conclusions: This study suggests the constituents of PM should be regularly investigated and evaluated related health effects, and considered in air quality management.

Oxidative potential and chemical composition of PM2.5 in office buildings across Europe – The OFFICAIR study

In the frame of the OFFICAIR project, indoor and outdoor PM2.5 samples were collected in office buildings across Europe in two sampling campaigns (summer and winter). The ability of the particles to deplete physiologically relevant antioxidants (ascorbic acid (AA), reduced glutathione (GSH)) in a synthetic respiratory tract lining fluid, i.e., oxidative potential (OP), was assessed. Furthermore, the link between particulate OP and the concentration of the PM constituents was investigated.The mean indoor PM2.5 mass concentration values were substantially lower than the related outdoor values with a mean indoor/outdoor PM2.5 mass concentration ratio of 0.62 and 0.61 for the summer and winter campaigns respectively. The OP of PM2.5 varied markedly across Europe with the highest outdoor OPAA m−3 and OPGSH m−3 (% antioxidant depletion/m3 air) values obtained for Hungary, while PM2.5 collected in Finland exhibited the lowest values. Seasonal variation could be observed for both indoor and outdoor OPAA m−3 and OPGSH m−3 with higher mean values during winter. The indoor/outdoor OPAA m−3 and OPGSH m−3 ratios were less than one with 4 and 17 exceptions out of the 40 cases respectively. These results indicate that indoor air is generally less oxidatively challenging than outdoors. Correlation analysis revealed that trace elements play an important role in determining OP, in particular, the Cu content. Indoor air chemistry might affect OP since weaker correlations were obtained for indoor PM2.5. Our findings also suggest that office workers may be exposed to health relevant PM constituents to a different extent within the same building.

Chemical composition of PM2.5 from two tunnels with different vehicular fleet characteristics

The chemical compositions of PM2.5 including OC, EC, water soluble ions, elements, and organic components such as polycyclic aromatic hydrocarbons (PAHs), hopanes, and steranes, emitted in Wuzushan (WZS) and Kuixinglou (KXL) tunnels were determined. WZS tunnel is a major route for diesel vehicles traveling, while KXL tunnel has limited to diesel vehicles. The results showed that the proportions of the different constituents of PM2.5 in the Wuzushan (WZS) tunnel were OC (27.7%), EC (32.1%), elements (13.9%), and water soluble ions (9.2%). Whereas the chemical profile of PM2.5 in the Kuixinglou (KXL) tunnel was OC (17.7%), EC (10.4%), elements (8.90%), and water soluble ions (8.87%). The emission factors (EFs) of PM2.5 and proportions of SO42− and Pb were decreased by vehicle emission standards and fuel quality policy in China, and the higher molecular weight PAHs (4+5+6 rings) were more abundant than the lower molecular weight PAHs (2+3 rings) in the two tunnels. The proportions of 17A(H)-21B(H)-30-Norhopane and 17A(H)-21B(H)-Hopane in the hopane and sterane were not dependent on the vehicles types. In addition, specific composition profiles for PM2.5 from gasoline-fueled vehicles (GV) and diesel-fueled vehicles (DV) emissions were drafted, which indicated that OC (0.974mg·veh−1·km−1) was the most abundant component in PM2.5, followed by Fe, Cl−, and Mg for GV. The relative proportions of the different constituents in the PM2.5 for DV were EC (35.9%), OC (27.2%), elements (12.8%), and water soluble ions (11.7%). Both the PM2.5 EFs and EC proportions in DV were higher than those in GV, and the HMW PAHs were the dominant PAHs for both GV and DV. The PM2.5 emissions from the vehicles in Yantai were 581±513tons to 1353±1197tons for GV, and 19,627±2477tons to 23,042±2887tons for DV, respectively.

Personal Exposure To PM2.5 (And Their Constituents) And Inflammatory Responses In Healthy Young Adults

Introduction: Fine particles (PM2.5) are associated with inflammation-related diseases and its toxicity changes with its composition. Therefore, the Identification of components with corresponding adverse health effects is important for effective air pollution control strategies. Several PM constituents such as black carbon, organic carbon, polycyclic aromatic hydrocarbons and phthalate esters have received much attention in the past and demonstrated potential of causing respiratory illness, while there are limited information about their associations with inflammation in healthy adults. Among the previous studies tried to examine the association, outdoor ambient concentrations were mostly used for PM2.5 exposure assessment, in stark contrast to the fact that young adults typically spend vast majority of their time in indoor environments. Characterizing personal exposure to PM2.5 and their chemical constituents is essential for accurate exposure assessment. Methods: The current study involves with 50 healthy young adults recruited from different districts of Hong Kong to undergo daily active personal PM2.5 monitoring (24 hours) in 6 consecutive days during summer and winter, respectively. At the end of each personal sampling day, exhaled nitric oxide was monitored and exhaled breath condensates along with urine samples were collected for biomarker monitoring. Personal activities and respiratory symptoms of all the subjects were recorded by self-reported diaries to check for health status and potential health influencing factors. Mixed effects model controlling for confounders was adopted to estimate the associations between repeated measurements of personal PM2.5 exposure and inflammatory biomarkers. Results: Preliminary result of summer season featured that PM2.5 was significantly associated with FeNO levels (p

Outdoor air pollution and health effects in urban children with moderate to severe asthma

Particulate matter less than 2.5 μm in diameter (PM2.5) is associated with asthma morbidity. Recent studies have begun examining the role of various constituents of PM2.5, their potential sources, and their effects on health. We examine their role in asthmatic children. Thirty-six children 6–14 years with moderate/severe asthma from inner city areas in New York City were studied for 2-week periods (summer and winter) using diaries and lung function. Outdoor data, including PM10, PM2.5, elements, elemental/organic carbon, and criteria gases (NO2, SO2, and O3) were collected at two sites. Odds ratios (ORs) relating daily pollutant concentrations to asthma indicators were calculated. During summer significant ORs>1 for symptom severity were obtained (O3, PM10, PM2.5, and S); after adjustment for O3, the ORs were no longer significant. During winter, Cu, Fe, Si, and Zn were significantly but negatively (ORs 1) on symptoms (As, K, Pb, and V). Albuterol use increased during summer (O3, PM10, PM2.5, Na, and S); after adjustment for O3, only Na and S remained significant. Reduced pulmonary function was significantly associated with O3 and Cl. Components of PM2.5 are associated with asthma exacerbation in asthmatic children. Same-day pollutant associations with symptoms are seen in summer. In winter, our analysis suggests delayed adverse associations of PM2.5 components.

Propagation behavior of elastic waves in one-dimensional piezoelectric/piezomagnetic phononic crystal with line defects

Using a stiffness matrix method, we investigate the propagation behaviors of elastic waves in one-dimensional (1D) piezoelectric/piezomagnetic (PE/PM) phononic crystals (PCs) with line defects by calculating energy reflection/transmittion coefficients of quasi-pressure and quasi-shear waves. Line defects are created by the replacement of PE or PM constituent layer. The defect modes existing in the first gap are considered and the influences on defect modes of the material properties and volume fraction of the defect layers, the type of incident waves, the location of defect layer and the number of structural layers are discussed in detail. Numerical results indicate that defect modes are the most obvious when the defect layers are inserted in the middle of the perfect PCs; the types of incidence wave and material properties of the defect layers have important effects on the numbers, the location of frequencies and the peaks of defect modes, and the defect modes are strongly dependent on volume fraction of the defect layers. We hope this paper will be found useful for the design of PE/PM acoustic filters or acoustic transducer with PCs structures.

Dust episodes in Beirut and their effect on the chemical composition of coarse and fine particulate matter

Particles captured during dust episodes in Beirut originated from both the African and Arabian deserts. This particular air mixture showed an increase, over non-dust episodes, in particle volume distribution which was mostly noticed for particles ranging in sizes between 2.25 and 5μm. It also resulted in an increase in average mass concentration by 48.5% and 14.6%, for the coarse and fine fractions, respectively. Chemical analysis of major aerosol components accounted for 93% of fine PM and 71% of coarse PM. Crustal material (CM) dominated the coarse PM fraction, contributing to 39±15% of the total mass. Sea salt (SS) (11±10%) and secondary ions (SI) (11±7%) were the second most abundant elements. In the fine fraction, SI (36±14%) were the most abundant PM constituent, followed by organic matter (OM) (33±7%) and CM (13±2%). Enrichment factors (EF) and correlation coefficients show that biogenic and anthropogenic sources contribute to the elemental composition of particles during dust episodes. This study emphasizes on the role played by the long-range transport of aerosols in changing the chemical composition of the organic and inorganic constituents of urban coarse and fine PM. The chemical reactions between aged urban and dust aerosols are enhanced during transport, leading to the formation of organo-nitrogenated and -sulfonated compounds. Their oligomeric morphologies are further confirmed by SEM–EDX measurements.