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Abstract A methodology to detect the weekly cycle impact of the particulate matter (PM), and PM sources on the near surface temperature and wind speed is discussed in the paper. Chemically-speciated PM10 and PM2.5 samples are analyzed to detect the weekly cycle of both the PM mass concentrations and the PM sources identified by the Positive Matrix Factorization technique. The average percent departure (APD) of the PM mass concentration from the mean value calculated for each day of the week shows that a positive (higher values during midweek) and a negative (higher values during weekend) weekly cycle characterizes the PM10 and PM2.5 mass concentrations in Autumn-Winter (AW, September–February) and Spring-Summer (SS, March–August), respectively. The westerly transport of pollution seems to have a role on the negative PM weekly cycle found in SS. The analysis of the six identified aerosol sources indicates that in SS the mixed anthropogenic and the reacted dust sources likely impact the PM10 negative weekly cycle and that the mixed anthropogenic source likely impacts the PM2.5 negative weekly cycle. The mixed anthropogenic and soil dust sources likely affect in AW the positive weekly cycle of the PM10 mass concentration. Both sources in addition to the reacted dust source seem to affect the PM2.5 mass concentration in AW. The APD analysis of the temperature (T) and wind speed (WS) at the surface from measurements co-located in space and time with the PM ones reveals that the WS and T values are characterized by a negative weekly cycle in AW. Conversely, in SS, the WS-APD value decreases on Sunday and the T-APD values increase in the second half of the week. These last results likely give evidence of the PM impact on the near-surface temperature and wind speed at the study site. Graphical abstract Unlabelled Image Highlights • Weekly cycles of PM10 and PM2.5 mass concentrations and seasonal dependence • Weekly cycles of temperature and wind speed at the surface and seasonal dependence • Chemical speciation of PM10 and PM2.5 samples • Aerosol source identification by Positive Matrix Factorization • Aerosol source impact on the weekly cycles of PM10 and PM2.5 mass concentrations [ABSTRACT FROM AUTHOR]

Abstract The real-time continuous measurements of non-refractory submicron aerosol (NR-PM 1) species including organics (Org), sulfate (SO 4 2−), nitrate (NO 3 −), ammonium (NH 4 +) and chloride (Cl−) in winter from 10 December 2015 to 30 January 2016 in Beijing were performed with an Aerodyne Aerosol Chemical Speciation Monitor (ACSM). The average concentration of NR-PM 1 was 81.24 μg m−3, with the mean concentration in heavy haze days being 220.00 μg m−3, ∼3 times higher than that in light haze days and ∼15 times higher than that in clean days. Org was the most significant component of NR-PM 1 species, accounting for 53% of the total NR-PM 1 for the entire study. SO 4 2− was also a significant component, accounting for 23% of the total NR-PM 1. However, NO 3 −, NH 4 + and Cl− composition together accounted for 25% of the total NR-PM 1. All NR-PM 1 species presented remarkably diurnal cycles in haze days, characterized by the highest concentrations occurring at midnight, and the lowest concentrations occurring at daytime. Note that the sulfur oxidation ratios were higher than the nitrogen oxidation ratios for the entire study, especially during the haze periods. The formation of sulfate was mainly affected by relative humidity (RH), while that of nitrate was more associated with NH 3. Heterogeneous oxidation of NO 2 on the surfaces of aerosol particles might be a significant pathway of nitrate formations during haze periods. NR-PM 1 was mainly from secondary chemical reactions contributing 46.1%, vehicle emissions contributing 22.3%, coal combustion contributing 16.1%, and biomass burning contributing 15.6% in clean days. However, compared to the clean-day source contributions, the haze-day secondary source contribution to NR-PM 1 increased to 66.8%, indicating that NR-PM 1 in haze days was dramatically dominated by the secondary pollutants. Highlights • The formation of sulfate was mainly affected by relative humidity (RH), while that of nitrate was more associated with NH 3. • Heterogeneous oxidation of SO 2 might be a significant pathway of sulfate formations during haze periods. • Heterogeneous oxidation of NO 2 might be a significant pathway of nitrate formations during haze periods. • NR-PM 1 in haze days was dramatically dominated by the secondary pollutants. [ABSTRACT FROM AUTHOR]

Abstract The Arctic region is undergoing significant changes in climate, with a notable decrease in summertime sea ice coverage over the past three decades. This trend means an increasing proportion of Arctic Ocean surface waters can receive direct deposition of material from the atmosphere, potentially influencing marine biogeochemical cycles and delivery of pollutants to the Arctic ecosystem. Here, we present aerosol concentrations of selected trace elements (Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb) measured during the US GEOTRACES Western Arctic cruise (GN01, also known as HLY1502) in August–October 2015. Concentrations of "lithogenic" elements (Al, Ti, V, Mn, Fe, and Co) were similar to those measured in remote and predominantly marine-influenced air masses in previous studies, reflecting the remoteness of the Arctic Ocean from major dust sources. Concentrations of Ni, Cu, Zn, Pb, and Cd showed significant enrichments over crustal values, and were often of similar magnitude to concentrations measured over the North Atlantic in air masses of North American or European provenance. We use 7Be inventory and flux data from GN01 to estimate a bulk atmospheric deposition velocity during the study period, and combine it with our aerosol concentrations to calculate atmospheric deposition fluxes of the trace elements in the Arctic region during late summer. The resulting estimates for mineral dust and Fe deposition fall at the low end of global estimates and confirm the Arctic Ocean as a low-dust environment during the summer months. This article is part of a special issue entitled: Conway GEOTRACES - edited by Tim M. Conway, Tristan Horner, Yves Plancherel, and Aridane G. González. Highlights • We report bulk aerosol concentrations of multiple trace elements from the western Arctic Ocean during summer 2015. • Deposition fluxes are calculated using a bulk deposition velocity calculated from aerosol and snow 7Be data. • Summertime atmospheric deposition fluxes of mineral dust and Fe to the Arctic are low relative to other oceanic regions. [ABSTRACT FROM AUTHOR]

Atmospheric PCDD/Fs and dl-PCBs samples were collected in Hochiminh city, Vietnam to address the effect of meteorological parameters, especially rainfall, on the occurrence and gas/particle partitioning of these persistent organic pollutants. The results indicate that PCDD/Fs and dl-PCBs concentrations in industrial site are higher than those measured in commercial and rural sites during both rainy and dry seasons. In terms of mass concentration, ambient PCDD/F levels measured in dry season are significantly higher than those measured in rainy season while dl-PCB levels do not vary significantly between rainy and dry seasons. The difference could be attributed to different gas/particle partitioning characteristics between PCDD/Fs and dl-PCBs. PCDD/Fs are found to be mainly distributed in particle phase while dl- PCBs are predominantly distributed in gas phase in both rainy and dry seasons. Additionally, Junge-Pankow and Harner-Bidleman models are applied to better understand the gas/particle partitioning of these pollutants in atmosphere. As a results, both PCDD/Fs and dl-PCBs are under non-equilibrium gas/particle partitioning condition, and PCDD/Fs tend to reach equilibrium easier in rainy season while there are no clear trend for dl-PCBs. Harner-Bidleman model performs better in evaluating the gas/particle partitioning of PCDD/Fs while Junge-Pankow model results in better prediction for dl-PCBs. [ABSTRACT FROM AUTHOR]

Equivalent black carbon ( E B C ) mass concentrations in the fine inhalable fraction of airborne particles ( P M 2.5 ) were determined using a 7-wavelength Aethalometer for 17 months, between November 2014 and March 2016, for a suburban location of the Metropolitan Area of Buenos Aires (MABA), Argentina. In addition to describing seasonal and diurnal black carbon (BC) cycles for the first time in this region, the relative contributions of fossil fuel and remote and local biomass burning were determined by distinguishing different carbonaceous components based on their effect on light attenuation for different wavelengths. Trajectory analyses and satellite-based fire products were used to illustrate the impact of long-range transport of particles emitted by non-local sources. EBC data showed a marked diurnal cycle, largely modulated by traffic variations and the height of the boundary layer, and a seasonal cycle with monthly median EBC concentrations (in μ g / m 3 ) ranging from 1.5 (February) to 3.4 (June). Maximum values were found during winter due to the combination of prevailingly stable atmospheric conditions and the increase of fossil fuel emissions, derived primarily from traffic and biomass burning from the domestic use of wood for heating. The use of charcoal grills was also detected and concentrated during weekends. The average contribution of fossil fuel combustion sources to E B C concentrations was 96%, with the remaining 4% corresponding to local and regional biomass burning. During the entire study period, only two events were identified during which E B C concentrations attributed to regional biomass burning accounted for over 50% of total E B C ; these events demonstrate the relevance of agricultural and forestry activities that take place far from the city yet whose emissions can affect the urban atmosphere of the MABA. [ABSTRACT FROM AUTHOR]

Integrating nephelometer measurements have been combined with co-located in space and time PM10 and PM1 mass concentration measurements to highlight the benefits of integrating aerosol optical properties with the chemical speciation of PM1 and PM10 samples. Inorganic ions (SO 4 2− , NO 3 − , NH 4 + , Cl − , Na + , K + , Mg 2+ , and Ca 2+ ), metals (Fe, Al, Zn, Ti, Cu, V, Mn, and Cr), and the elemental and organic carbon (EC and OC, respectively) have been monitored to characterize the chemical composition of PM1 and PM10 samples, respectively. The scattering coefficient ( σ p ) at 450 nm, the scattering Ångström coefficient ( Å ) calculated at the 450–635 nm wavelength pair, and the scattering Ångström coefficient difference (∆ Å ) retrieved from nephelometer measurements have been used to characterize the optical properties of the particles at the surface. The frequency distribution of the Å daily means during the one-year monitoring campaign, performed at a southeastern Italian site, has allowed identifying three main Å variability ranges: Å  ≤ 0.8, 0.8 <  Å  ≤ 1.2, and Å  > 1.2. We found that σ p and ∆ Å mean values and the mean chemical composition of the PM1 and PM10 samples varied with the Å variability range. σ p and ∆ Å reached the highest (149 Mm −1 ) and the smallest (0.16) mean value, respectively, on the days characterized by Å  > 1.2. EC, SO 4 2− , and NH 4 + mean mass percentages also reached the highest mean value on the Å  > 1.2 days, representing on average 8.4, 9.8, and 4.2%, respectively, of the sampled PM10 mass and 12.4, 10.6, and 7.7%, respectively, of the PM1 mass. Conversely, σ p and ∆ Å mean values were equal to 85 Mm −1 and 0.55, respectively, on the days characterized by Å  ≤ 0.8 and the EC, SO 4 2− , and NH 4 + mean mass percentages reached smaller values on the Å  ≤ 0.8 days, representing 4.5, 6.0, and 1.9% of the PM10 mass and 9.4, 7.3, and 5.8% of the PM1 mass, respectively. Primary and secondary OC (POC and SOC, respectively) contributions also varied with the Å variability range. POC and SOC mean mass percentages reached the highest and the smallest value, respectively, on the days characterized by Å  > 1.2. Conversely, POC and SOC mean mass percentages reached the smallest and the highest value, respectively, on the days characterized by Å  ≤ 0.8. It has also been shown that the PM, OC, OC + EC, POC, and SOC mass scattering cross sections varied significantly with the Å variability range, because of the Å dependence on aerosol sources and/or emission, transport, and transformation mechanisms. Therefore, it has been shown that Å daily mean values can represent a good tool to better differentiate the chemical speciation of size-fractioned PM samples. [ABSTRACT FROM AUTHOR]

Objectives There are two platforms for the detection of Lp-PLA 2 in sera or plasmas: by its enzymatic activity (PLAC® activity test) and by its mass concentration (PLAC® mass test). It has been long recognized that these two platforms are not correlated well. The underlying cause for this is therefore investigated by the biochemical characterization of the two PLAC tests. Design & methods Human sera with and without the treatment by detergent were fractionated by using a Superose-6 column in phosphate buffered saline and the phospholipid associated Lp-PLA 2 was assessed by both PLAC mass and activity tests. The Lp-PLA 2 values of the two PLAC tests were compared under such conditions. Results Fractionation of sera and plasmas indicates that the association of Lp-PLA 2 with phospholipids, especially LDL and other large size phospholipid vesicles, may block the detection of the enzyme by antibodies in the immunoassay format under the conditions of the PLAC mass test. Inclusion of high concentration (> CMC, critical micelle concentration) of detergents in the assay buffer of PLAC mass test dissociates Lp-PLA 2 from phospholipid vesicles and results in the full detection of all Lp-PLA 2 in sera or plasmas for concentration. Such assay modification significantly improves the correlation between the PLAC mass and PLAC activity tests. Conclusions PLAC mass test only detects a small portion of the total Lp-PLA 2 , mainly the Lp-PLA 2 associated with HDL. This is the main cause of the discordance and poor correlation between the PLAC mass and activity tests. Our results demonstrate the PLAC activity test is more accurate in assessing the total level of circulating Lp-PLA 2 . [ABSTRACT FROM AUTHOR]

This paper presents a new discrete physical model to approach the problem of cracked beam vibrations. The model consists of a beam made of several small and evenly spaced bars. The beam bending stiffness is modeled by spiral springs that serve also as a crack model. Concentrated masses presenting the inertia of the beam are located at the bar ends. This model has the advantage of simplifying parametric studies, because of its discrete nature, allowing easy modification in the crack position and magnitude. Therefore, once the model is established, various practical applications may be performed without the need to go through all the formulations again. As a result, this model allows conducting a parametric study with the objective of facilitating the diagnostics process involving both crack localization and depth estimation. [ABSTRACT FROM AUTHOR]

This study aims to determine the seasonal variations and composition of suspended particulate matter in different sizes PM 1.0 , PM 2.5 , PM 10 and the total suspended particles (TSP) emitted at major intra-urban traffic intersections (TIs) of Ilorin metropolis. The concentration levels of PM (PM 1.0 , PM 2.5 , PM 10 ) obtained at the TIs during the rush hours (45.1, 77.9, and 513 μg/m 3 ) are higher than the levels obtained for the non-rush hour periods (42.3, 62.7, and 390 μg/m 3 ). The average on-road respiratory deposition dose (RDD) rates of PM 1.0 , PM 2.5 and PM 10 during the dry period at TIs types was found to be about 24%, 9% and 25% higher than those obtained during the wet period. Based on EF values calculated, Pb and Zn were anthropogenically-derived while Fe, Mn, Cr, Cu and Mg were of crustal source. Principal component analysis (PCA) has been applied to a set of PM data in order to determine the contribution of different sources. It was found that the main principal factors extracted from particulate emission data were related to exhaust and non-exhaust emissions such as tyre wears, oil and fuel combustion sources. [ABSTRACT FROM AUTHOR]

We present a study characterizing aerosol particles resulting from a skyscraper blasting. High PM 10 mass concentrations with a maximum of 844.9 μg m -3 were present for a short time period of approximately 15 minutes. They result in a day mean of 32.6 μg m -3 compared to a 27.6 μg m -3 background not exceeding the 50 μg m -3 EU maximum permissive value. The increase in particle number concentration was less pronounced with a maximum concentration of 6.9 ⋅ 10 4 cm -3 compared to the local background value of 1.8 ⋅ 10 4 cm -3 . The size-resolved number concentration shows a single mode of ultrafine particles at approximately 93 nm. The spatial distribution of deposited dust was investigated with Bergerhoff glass collection vessels, showing a decrease with distance. In the deposited dust samples the concentrations of twelve metals was determined, non of them exceeded the regional background concentrations significantly. The chemical composition of individual particles emitted by the demolition was studied by Scanning Electron Microscopy. They were mainly concrete and steel particles, with 60% calcium carbonates, 19% calcium sulfates, 19% silicates and 2% steel. In energy-dispersive X-Ray Spectroscopy, no fibers like asbestos were observed. Using a broad spectrum of instruments and methods, we obtain comprehensive characterization of the particles emitted by the demolition. [ABSTRACT FROM AUTHOR]

In present study, the effect of fuel premixing ratio, direct fuel injection timings and engine compression ratio on the soot particle emissions in nano-size range from a non-road compression ignition engine is investigated. Experiments are conducted on modified dual fuel single cylinder engine at 1500 rpm. To run the engine in dual fuel mode, port fuel injection (PFI) system is installed by modifying intake manifold of the engine and developing a PFI controller. Experiments are conducted for various fuel premixing ratio of gasoline/methanol-diesel at different engine load, diesel fuel injection timing and compression ratios. Differential mobility spectrometer based particle sizer is used for investigation of the soot particle number-size distribution, surface area-size distribution, particle mass-size distribution and total particle number concentration from the engine exhaust at various test conditions. Results revealed that total particle number concentration is higher at full engine load and increases with fuel premixing ratio (especially in case of methanol-diesel dual fuel operation). Additionally, the peak particle number and mass concentration reduces with an increase in compression ratio of the engine. [ABSTRACT FROM AUTHOR]

A mathematical model which can help to calculate the separation efficiency of streamlined plate gas-liquid separator was derived on the basis of the plug flow model. Both experiment and simulation were carried out to verify the model results. In the experiment, an aerosol spectrometer measurement system Promo-3000 by Palas Germany was used for measuring the size distribution and mass concentration of water droplets in the inlet and outlet and further to obtain the grade separation efficiency. Then the performance of the streamlined plates was evaluated at different gas velocities. In simulation, Realizable k-ε and enhanced wall treatment were applied in Fluent 14.5 with the same conditions as that in experiment. The results show that the model results agree well with that from experiment and simulation on the variation tendency of efficiency. The turning angle in space and the width of outlet are two main factors influencing the performance of streamlined plate gas-liquid separator. To increase the angle and reduce the width in every concave or convex channel space can obviously improve the efficiency. A new universal method to design and optimize corrugated plate geometry was provided. According to the model result and this method, the economical and high-efficient variant plates are put forward, which are significant to the industrial application. [ABSTRACT FROM AUTHOR]

We measured physical properties and optical properties of the black carbon (BC) generated in a spark discharger which did not produce soluble organic fractions. Effective densities and absorption cross-sections of the fresh BC were estimated using the electrical mobility diameter, the number concentration and the mass concentration. Size distribution measurements using a differential mobility analyzer (DMA) and a condensation particle counter (CPC) showed that the mode diameter and the number concentration increased with increasing spark frequency of the spark discharger. The primary particle size was also measured through the analysis of images observed using a field emission scanning electron microscope (FESEM), decreasing from 36.3 to 15.1 nm with increasing a spark frequency. The effective densities were estimated from 0.054 to 1.392 g/cm 3 and compared to be lower than those of atmospheric aerosols which might be aged. The absorption cross-sections were estimated as 1.0×10 –15 to 1.7×10 –15 m 2 depending on spark frequency. For the BC generated at a fixed constant spark frequency, the absorption cross-section was estimated to be larger as the BC became bigger in electrical mobility diameter. For the BC having the same electrical mobility diameter generated at different spark frequencies, however, the absorption cross-section generated at a faster spark frequency was smaller. Fractal dimension for the BC larger than 160 nm was measured to be 1.79, which is very similar to that for the spark-generated BC studied by other research group. In conclusion, the effective density allowed us to distinguish the core BC from aged BC. [ABSTRACT FROM AUTHOR]

Recently, inexpensive (<$300) consumer aerosol monitors (CAMs) targeted for use in homes have become available. We evaluated the accuracy, bias, and precision of three CAMs (Foobot from Airoxlab, Speck from Carnegie Mellon University, and AirBeam from HabitatMap) for measuring mass concentrations in occupational settings. In a laboratory study, PM 2.5 measured with the CAMs and a medium-cost aerosol photometer (personal DataRAM 1500, Thermo Scientific) were compared to that from reference instruments for three aerosols (salt, welding fume, and Arizona road dust, ARD) at concentrations up to 8500 µg/m 3 . Three of each type of CAM were included to estimate precision. Compared to reference instruments, mass concentrations measured with the Foobot (r-value = 0.99) and medium-cost photometer (r-value=0.99) show strong correlation, whereas those from the Speck (r-value range 0.91-0.99) and AirBeam (0.7–0.96) were less correlated. The Foobot bias was (−12%) for ARD and measurements were similar to the medium-cost instrument. Foobot bias was (<−46%) for salt and welding fume aerosols. Speck bias was at 18% for ARD and −86% for welding fume. AirBeam bias was (−36%) for salt and (−83%) for welding fume. All three photometers had a bias (<−82%) for welding fume. Precision was excellent for the Foobot (coefficient of variation range: 5–8%) and AirBeam (2–9%), but poorer for the Speck (8–25%). These findings suggest that the Foobot, with a linear response to different aerosol types and good precision, can provide reasonable estimates of PM 2.5 in the workplace after site-specific calibration to account for particle size and composition. [ABSTRACT FROM AUTHOR]

Sixteen U.S. EPA priority polycyclic aromatic hydrocarbons (PAHs) and eleven non-priority isomers including some dibenzopyrenes were analyzed to evaluate health risk attributable to inhalation exposure to ambient PAHs and contributions of the non-priority PAHs in a megacity Nanjing, east China. The annual average mass concentration of the total 16 EPA priority PAHs in air was 51.1 ± 29.8 ng/m3, comprising up to 93% of the mass concentration of all 27 PAHs, however, the estimated Incremental Lifetime Cancer Risk (ILCR) due to inhalation exposure would be underestimated by 63% on average if only accounting the 16 EPA priority PAHs. The risk would be underestimated by 13% if only particulate PAHs were considered, though gaseous PAHs made up to about 70% of the total mass concentration. During the last fifteen years, ambient Benzo[a]pyrene decreased significantly in the city which was consistent with the declining trend of PAHs emissions. Source contributions to the estimated ILCR were much different from the contributions for the total mass concentration, calling for the introduce of important source-oriented risk assessments. Emissions from gasoline vehicles contributed to 12% of the total mass concentration of 27 PAHs analyzed, but regarding relative contributions to the overall health risk, gasoline vehicle emissions contributed 45% of the calculated ILCR. Dibenzopyrenes were a group of non-priority isomers largely contributing to the calculated ILCR, and vehicle emissions were probably important sources of these high molecular weight isomers. Ambient dibenzo[a,l]pyrene positively correlated with the priority PAH Benzo[g,h,i]perylene. The study indicates that inclusion of non-priority PAHs could be valuable for both PAH source apportionment and health risk assessment. [ABSTRACT FROM AUTHOR]

Background Exposure to indoor VOCs is expected to link to a variety of negative health outcome. The popularity of decorations and refurbishment in homes in China has given rise to indoor elevated VOC levels, potentially posing health threats to residents. Methods In this study, concentrations of 101 VOC compounds and associated health risks were investigated in newly renovated homes in Shanghai. The potential excess inhalation health risks from home exposure of 17 health-related VOCs were estimated by the Inhalation Unit Risk (IUR) and Reference Concentration (RfC) proposed by US EPA. Monte Carlo simulation and sensitivity analysis were used to assess the uncertainty associated with the estimates of health risks. Results The dominant groups by mass concentration were oxygenated VOCs (o-VOCs), aromatics, alkanes and halogenated VOCs (x-VOCs) .12 VOCs with IARC's confirmed or probable carcinogens ratings were detected with a > 60% detection frequency in the total samples. The mean concentrations of BTEX (benzene, toluene, m / p -xylene, o -xylene, ethylbenzene) were 2.32 μg/m 3 , 200.13 μg/m 3 , 39.56 μg/m 3 , 32.59 μg/m 3 and 26.33 μg/m 3 respectively, generally higher than those in older homes reported in previous studies except benzene. The mean concentration of methylene chloride (47.43 μg/m 3 ) and 1,2-dichloroethane (33.83 μg/m 3 ) were noticeably higher than the levels reported in previous studies in Hong Kong, Japan and Canada. Whereas the mean concentration of 1,4-dichlorobenzene (5.53 μg/m 3 ) were similar to the results of Canadian national survey but lower than those in Japan. The concentrations of 1,2-dichloroethane, 1,4-dichlorobenzene, and methylene chloride, ethylbenzene presented a mean cancer risk at 7.39 × 10 − 6 , 1.95 × 10 − 6 , 1.62 × 10 − 6 , 1.04 × 10 − 6 respectively, above the US EPA proposed acceptable risk level of 1 × 10 − 6 . Sensitivity analyses indicated that the VOC exposure concentration have a greater impact than the IUR values on the risk assessment. Conclusion This study highlights the characteristics of VOCs in recently renovated homes and has implications for the adverse health effects that result from exposure to chlorinated hydrocarbons in indoor air. [ABSTRACT FROM AUTHOR]

We present a high resolution model of the linear trend in the Earth's mass variations based on DMT-2 (Delft Mass Transport model, release 2). DMT-2 was produced primarily from K-Band Ranging (KBR) data of the Gravity Recovery And Climate Experiment (GRACE). It comprises a time series of monthly solutions complete to spherical harmonic degree 120. A novel feature in its production was the accurate computation and incorporation of stochastic properties of coloured noise when processing KBR data. The unconstrained DMT-2 monthly solutions are used to estimate the linear trend together with a bias, as well as annual and semi-annual sinusoidal terms. The linear term is further processed with an anisotropic Wiener filter, which uses full noise and signal covariance matrices. Given the fact that noise in an unconstrained model of the trend is reduced substantially as compared to monthly solutions, the Wiener filter associated with the trend is much less aggressive compared to a Wiener filter applied to monthly solutions. Consequently, the trend estimate shows an enhanced spatial resolution. It allows signals in relatively small water bodies, such as Aral sea and Ladoga lake, to be detected. Over the ice sheets, it allows for a clear identification of signals associated with some outlet glaciers or their groups. We compare the obtained trend estimate with the ones from the CSR-RL05 model using (i) the same approach based on monthly noise covariance matrices and (ii) a commonly-used approach based on the DDK-filtered monthly solutions. We use satellite altimetry data as independent control data. The comparison demonstrates a high spatial resolution of the DMT-2 linear trend. We link this to the usage of high-accuracy monthly noise covariance matrices, which is due to an accurate computation and incorporation of coloured noise when processing KBR data. A preliminary comparison of the linear trend based on DMT-2 with that computed from GSFC_global_mascons_v01 reveals, among other, a high concentration of the signal along the coast for both models in areas like the ice sheets, Gulf of Alaska, and Iceland. [ABSTRACT FROM AUTHOR]

Mass concentrations of PM2.5, mineral dust, organic carbon (OC) and elemental carbon (EC), water-soluble organic carbon (WSOC), sea salts and anthropogenic metals have been studied in a city-port of south Italy (Brindisi). This city is characterized by different emission sources (ship, vehicular traffic, biomass burning and industrial emissions) and it is an important port and industrial site of the Adriatic sea. Based on diagnostic ratios of carbonaceous species we assess the presence of biomass burning emissions (BBE), fossil fuel emissions (FFE) and ship emission (SE). Our proposed conversion factors from OC to OM are higher than those reported in the literature for urban site: the reason of this could be due to the existence of aged combustion aerosols during the sampling campaign (WSOC/OC = 0.6 ± 0.3). [ABSTRACT FROM AUTHOR]

The fine particulate matter, generally known as PM 2.5 , has great impact on the air quality and human health. Although closing external windows can help prevent outdoor PM 2.5 going into indoors, many studies have shown that a significant number of particles can still pass the building façade through the cracks around the window. In order to quantify the influence of the external window crack structure and some relevant parameters, such as room dimension, on the indoor PM 2.5 mass concentration, this paper introduces an updated model from a previously published paper by the authors [18]. The model was developed based on two-month field measured data from five unoccupied offices located in the central area of Beijing (capital city located in northern China), and then was validated against a new dataset measured in Guangzhou (a major city located in southern China). The model can be used to quantify the indoor PM 2.5 mass concentration based on the instant outdoor PM 2.5 level, considering influences from external window crack structure, room dimension and outdoor meteorological conditions, i.e. outdoor wind speed and relative humidity. [ABSTRACT FROM AUTHOR]

This paper describes the aerosols optical, physical characteristics and the aerosol radiative forcing pertaining to semi-arid region, Anantapur for the period January 2013-December 2014. Collocated measurements of Aerosol Optical Depth (AOD) and Black Carbon mass concentration (BC) are carried out by using MICROTOPS II and Aethalometer and estimated the aerosol radiative forcing over this location. The mean values of AOD at 500 nm are found to be 0.47 ± 0.09, 0.34 ± 0.08, 0.29 ± 0.06 and 0.30 ± 0.07 during summer, winter, monsoon and post-monsoon respectively. The Angstrom exponent (α 380–1020 ) value is observed maximum in March (1.25 ± 0.19) and which indicates the predominance of fine - mode aerosols and lowest in the month of July (0.33 ± 0.14) and may be due to the dominance of coarse-mode aerosols. The diurnal variation of BC is exhibited two height peaks during morning 07:00–08:00 (IST) and evening 19:00–21:00 (IST) hours and one minima noticed during afternoon (13:00–16:00). The highest monthly mean BC concentration is observed in the month of January (3.4 ± 1.2 μg m − 3 ) and the lowest in July (1.1 ± 0.2 μg m − 3 ). The estimated Aerosol Direct Radiative Forcing (ADRF) in the atmosphere is found to be + 36.8 ± 1.7 W m − 2 , + 26.9 ± 0.2 W m − 2 , + 18.0 ± 0.6 W m − 2 and + 18.5 ± 3.1 W m − 2 during summer, winter, monsoon and post-monsoon seasons, respectively. Large difference between TOA and BOA forcing is observed during summer which indicate the large absorption of radiant energy (36.80 W m − 2 ) which contributes more increase in atmospheric heating by ~ 1 K/day. The BC contribution on an average is found to be 64% and is responsible for aerosol atmospheric heating. [ABSTRACT FROM AUTHOR]

Continuous measurements of suspended sediment mass concentration (SSC) and particle size distribution (PSD) in surface waters and hydraulic schemes are of prime importance for the investigation and management of many fine-sediment related processes. In this paper, the performance of selected techniques and instruments for continuous SSC measurements is discussed based on results of a field study and a recent literature-review paper. SSCs measured with Laser In Situ-Scattering and Transmissometry (LISST) or vibrating tube densimetry were confirmed to be not or less biased by temporary PSD variations than SSCs obtained from turbidimeters or a single-frequency acoustic attenuation method. Vibrating tube densimetry allowed measurements of higher SSCs (e.g. 10 g/l) compared to the other investigated instruments. For the conversion of the instruments’ outputs to SSC, i.e. calibration, and for validation, gravimetric analysis of bottle samples is recommended as reference. [ABSTRACT FROM AUTHOR]

The total count number concentration of particles from 10 to 1000 nm, particle size distribution, and PM 2.5 (aerodynamic diameter ≤ 2.5 μm) mass concentration were measured on a parking apron next to the runway at Tianjin International Airport in China. The data were collected 250, 270, 300, 350, and 400 m from the runway. Wind direction and wind speed played important roles in determining the characteristics of the atmospheric particles. An inverted U-shaped relationship was observed between the measured particle number concentration and wind speed, with an average peak concentration of 2.2 × 10 5 particles/cm 3 at wind speeds of approximately 4–5 m/s. The atmospheric particle number concentration was affected mainly by aircraft takeoffs and landings, and the PM 2.5 mass concentration was affected mainly by the relative humidity (RH) of the atmosphere. Ultrafine particles (UFPs, diameter < 100 nm), with the highest number concentration at a particle size of approximately 16 nm, dominated the measured particle size distributions. The calculated particle emission index values for aircraft takeoff and landing were nearly the same, with mean values of 7.5 × 10 15 particles/(kg fuel) and 7.6 × 10 15 particles/(kg fuel), respectively. The particle emission rate for one aircraft during takeoff is two orders of magnitude higher than for all gasoline-powered passenger vehicles in Tianjin combined. The particle number concentrations remained much higher than the background concentrations even beyond 400 m from the runway. [ABSTRACT FROM AUTHOR]

This paper presents aerosol light absorption measurements using a seven channel Aethalometer (AE-42), recorded during September 2011–November 2012 over a tropical semi-arid site in Kadapa, India. The annual average black carbon (BC) mass concentration ([BC]) during the studied period was 2.20 ± 0.78 μg m − 3 which is in agreement when compared to other sites of similar environment. Strong seasonal variation was observed with high values during winter (2.87 ± 0.81 μg m − 3 ) and low in monsoon (1.30 ± 0.31 μg m − 3 ) season, which could be attributed to regional synoptic meteorology and long range transport. The two peaks in diurnal variations of [BC] were observed during morning between 06:00 and 08:00 h local time (LT) and in the evening around 19:00–21:00 h LT, with a minimum peak in the afternoon (~ 16:00 h LT) which is strongly correlated with the boundary layer dynamics, local and regional sources, and associated meteorology. The relationships between measured [BC] and the corresponding meteorological parameters for the studied region were also analysed. The estimated monthly mean spectral absorption coefficient values range from 0.56 to 1.15 with an average of 0.90, which suggests high BC/OC ratio and possible source of emission of aerosols is fossil fuel burning. Trajectory cluster analysis showed significant impact of long range transport of BC aerosols towards the observational site during the period of study. [ABSTRACT FROM AUTHOR]

This paper describes the use of a unique valve switching system that allowed for high temporal resolution indoor and outdoor data to be collected concurrently from online C-ToF-AMS, SMPS and OC/EC, and offline BLPI measurements. The results reveal near real-time dynamic aerosol behaviour along a migration path from an outdoor to indoor environment. An outdoor reduction in NR-PM 1 mass concentration occurred daily from AM (06:00–12:00) to PM (12:00–18:00). SO 4 (26%–37%) [AM/PM] increased proportionally during afternoons at the expense of NO 3 (18%–7%). The influences of mixing height, temperature and solar radiation were considered against the mean mass concentration loss for each species. Losses were then calculated according to species via a basic input/output model. NO 3 lost the most mass during afternoon periods, which we attribute to the accelerated dissociation of NH 4 NO 3 through increasing temperature and decreasing relative humidity. Indoor/outdoor (I/O) ratios varied from 0.46 for <40 nm to 0.65 for >100 nm. These ratios were calculated using average SMPS PNC measurements over the full campaign and corroborated using a novel technique of calculating I/O penetration ratios through the indoor migration of particles during a new particle formation event. This ratio was then used to observe changes in indoor composition relative to those outdoors. Indoor sampling was carried out in an undisturbed room with no known sources. Indoor concentrations were found to be proportional to those outdoors, with organic matter [2.7 μg/m 3 ] and SO 4 [1.7 μg/m 3 ] being the most prominent species. These results are indicative of fairly rapid aerosol penetration, a source-free indoor environment and small afternoon I/O temperature gradients. Fine fraction NO 3 was observed indoors in both real-time AMS PM 1 and off-line BLPI measurements. Greater mass concentration losses were observed from filter measurements, highlighting an important time dependency factor when investigating semi-volatiles. Coarse mode NO 3 was observed by impactor measurements, ascribing value to observing the full particle mass size distribution for understanding aerosol origin. [ABSTRACT FROM AUTHOR]

Ambient PM 2.5 pollution is a substantial threat to public health in global megacities. This paper reviews the PM 2.5 pollution of 45 global megacities in 2013, based on mass concentration from official monitoring networks and composition data reported in the literature. The results showed that the five most polluted megacities were Delhi, Cairo, Xi'an, Tianjin and Chengdu, all of which had an annual average concentration of PM 2.5 greater than 89 μg/m 3 . The five cleanest megacities were Miami, Toronto, New York, Madrid and Philadelphia, the annual averages of which were less than 10 μg/m 3 . Spatial distribution indicated that the highly polluted megacities are concentrated in east-central China and the Indo-Gangetic Plain. Organic matter and SNA (sum of sulfate, nitrate and ammonium) contributed 30% and 36%, respectively, of the average PM 2.5 mass for all megacities. Notable seasonal variation of PM 2.5 polluted days was observed, especially for the polluted megacities of China and India, resulting in frequent heavy pollution episodes occurring during more polluted seasons such as winter. Marked differences in PM 2.5 pollution between developing and developed megacities require more effort on local emissions reduction as well as global cooperation to address the PM 2.5 pollution of those megacities mainly in Asia. [ABSTRACT FROM AUTHOR]

Daily PM 2.5 (particulate matter with an aerodynamic diameter of below 2.5 μm) mass concentrations were measured by gravimetric analysis in Chinese Research Academy of Environmental Sciences (CRAES), in the northern part of the Beijing urban area, from December 2013 to April 2015. Two pairs of Teflon (T1/T2) and Quartz (Q1/Q2) samples were obtained, for a total number of 1352 valid filters. Results showed elevated pollution in Beijing, with an annual mean PM 2.5 mass concentration of 102 μg/m 3 . According to the calculated PM 2.5 mass concentration, 50% of our sampling days were acceptable (PM 2.5 < 75 μg/m 3 ), 30% had slight/medium pollution (75–150 μg/m 3 ), and 7% had severe pollution (> 250 μg/m 3 ). Sampling interruption occurred frequently for the Teflon filter group (75%) in severe pollution periods, resulting in important data being missing. Further analysis showed that high PM 2.5 combined with high relative humidity (RH) gave rise to the interruptions. The seasonal variation of PM 2.5 was presented, with higher monthly average mass concentrations in winter (peak value in February, 422 μg/m 3 ), and lower in summer (7 μg/m 3 in June). From May to August, the typical summer period, least severe pollution events were observed, with high precipitation levels accelerating the process of wet deposition to remove PM 2.5 . The case of February presented the most serious pollution, with monthly averaged PM 2.5 of 181 μg/m 3 and 32% of days with severe pollution. The abundance of PM 2.5 in winter could be related to increased coal consumption for heating needs. [ABSTRACT FROM AUTHOR]

This study presents a method to retrieve vertically-resolved profiles of dust mass concentrations by analyzing Raman lidar signals of silicon dioxide (quartz) at 546 nm. The observed particle plumes consisted of mixtures of East Asian dust with anthropogenic pollution. Our method for the first time allows for extracting the contribution of the aerosol component “pure dust” contained in the aerosol type “polluted dust”. We also propose a method that uses OPAC (Optical Properties of Aerosols and Clouds) and the mass concentrations profiles of dust in order to derive profiles of backscatter coefficients of pure dust in mixed dust/pollution plumes. The mass concentration of silicon dioxide (quartz) in the atmosphere can be estimated from the backscatter coefficient of quartz. The mass concentration of dust is estimated by the weight percentage (38–77%) of mineral quartz in Asian dust. The retrieved dust mass concentrations are classified into water soluble, nucleation, accumulation, mineral-transported and coarse mode according to OPAC. The mass mixing ratio of 0.018, 0.033, 0.747, 0.130 and 0.072, respectively, is used. Dust extinction coefficients at 550 nm were calculated by using OPAC and prescribed number concentrations for each of the 5 components. Dust backscatter coefficients were calculated from the dust extinction coefficients on the basis of a lidar ratio of 45 ± 3 sr at 532 nm. We present results of quartz-Raman measurements carried out on the campus of the Gwangju Institute of Science and Technology (35.10°N, 126.53°E) on 15, 16, and 21 March 2010. [ABSTRACT FROM AUTHOR]

Visibility, particulate matter (PM) mass concentration, and aerosol optical properties data from June 2009 to December 2011 were obtained at Shenyang in Northeast China. The characteristics and relationships between these parameters were statistically analyzed. The results demonstrate that the monthly averaged visibility over Shenyang was higher in spring and autumn but lower in summer and winter, and had an inverse trend to PM and aerosol optical depth (AOD). Higher AOD at 500 nm was found year by year, with the maximum value (1.31 ± 0.45) occurring in June 2011, and the minimum in June 2010 (0.72 ± 0.31). The mean value of the Ångström exponent underwent a notable reduction during the period of 2011, with values less than 1.0 from February to September. The single scattering albedo was consistently around 0.90 during 2009–2011, which was higher in summer but lower in winter. The higher absorption aerosol optical depth at 440 nm in 2011 indicates that there were more absorbing aerosol particles in this period compared with the corresponding absorption Ångström exponent in the same year (about 0.75). The direct radiative forcing at the bottom of the atmosphere increased to − 200 W/m 2 in 2011, compared with − 150 W/m 2 from June 2009 to December 2010, suggesting a stronger cooling effect of aerosols at the surface. The positive radiative forcing at the top of the atmosphere in November and December 2009 could have been due to snow cover, which has a large surface albedo that reflects shortwave radiation to the atmosphere. [ABSTRACT FROM AUTHOR]

In this paper, a model consisting of the lattice Boltzmann (LB) method for fluid flow and mass transport and the cellular automata probabilistic method employed for simulating the movement of airborne particles to predict the transport process of indoor semi-volatile organic compounds (SVOCs) is developed. This model is used to obtain the concentration distribution of the airborne di-2-ethylhexyl phthalate (DEHP), a typical SVOC, including the gas-phase DEHP and the particle-phase DEHP in the given indoor environment where the vinyl flooring is the only emission source. Research on the influence of airborne particles on the transport of indoor airborne DEHP is made through comparing concentration distribution of DEHP in the cases of different airborne particle mass concentration and diameter, respectively. The DEHP emission rate under different ventilation types is also studied. Simulation results show that the airborne particle concentration directly affects the indoor DEHP emission. The increase of the indoor airborne particle mass concentration or the decrease of the airborne particle diameter will both help reduce the gas phase DEHP concentration. The emission rate increases with the increase of the airborne particle concentration. The indoor DEHP pollution will be reduced when the air changes per hour (ACH) increases. In general, Comparing with the cross ventilation method, the displacement one is more beneficial to reduce indoor DEHP pollution. [ABSTRACT FROM AUTHOR]

A novel in-situ, real time method for the determination of inherent absorption properties of light absorbing carbonaceous particulate matter and its possible application for source apportionment are introduced here. The method is deduced from a two-week campaign under wintry urban conditions during which strong correlation was found between aerosol number size distribution and wavelength dependent optical absorption coefficient ( AOC(λ) ), measured by a Single Mobility Particle Sizer (SMPS) and a multi-wavelength photoacoustic absorption spectrometer, respectively, while wood burning and traffic (i.e. fossil fuel burning) activity were identified to be the dominant sources of carbonaceous particulate. Indeed, during the whole campaign, regardless of the actual emission strength of the aerosol sources, the measured number size distributions were always dominated by two unimodal modes with Count Mean Diameter (CMD) of 20 and 100 nm, which could be correlated to traffic and wood burning activities, respectively. AAE ff , AAE wb (i.e. the Aerosol Angström Exponent of traffic and wood burning aerosol, respectively), σ ff (266 nm) , σ ff (1064 nm) , σ wb (266 nm) and σ ff (1064 nm) (i.e. the segregated mass specific optical absorption coefficients at two of the measurement wavelengths) were found to be 1.17 ± 0.18, 2.6 ± 0.14, 7.3 ± 0.3 m 2 g −1 , 1.7 ± 0.1 m 2 g −1 3.4 ± 0.3 m 2 g −1 and 0.31 ± 0.08 m 2 g −1 , respectively. Furthermore the introduced methodology can also disentangle and quantify the temporal variation of both the segregated optical absorptions and the segregated mass concentrations of traffic and wood burning aerosol. Accordingly, the contribution of wood burning to optical absorption of PM was found to be negligible at 1064 nm but increased gradually towards the shorter wavelengths and became commensurable with the optical absorption of traffic at 266 nm during the whole measurement period. Furthermore, the contribution of wood burning mass to CM (mass of carbonaceous particulate matter) was dominant regardless of the strength of the emission activity of traffic and wood burning during the whole measurement period. [ABSTRACT FROM AUTHOR]

Mare Crisium is composed of a set of volcanic deposits situated in an impact basin on the Moon's near side. The topography of the mare is dominated by an annulus of elevated topography, the inner edge of which is delineated by basin-concentric wrinkle ridges. From a combination of remotely sensed image and topographic data and numerical modeling, we show that the thrust faults that underlie these ridges penetrate up to 20 km in depth, considerably below the base of the mare deposits themselves. Thrust faults of this scale have not heretofore been recognized on the Moon. Mare Crisium sits above a region of uplifted mantle, which contributes to a mass excess beneath the basin, and we demonstrate by comparison with free-air gravity anomaly and derived crustal thickness data for Crisium that the thrust faults structurally bound this elevated mantle material. By means of finite-element models of stresses induced by lithospheric loading within the basin, we argue that the deep-seated thrusts may have been localized by the boundary between the superisostatic mantle material and a sub-isostatic collar of thickened crust that resulted from basin formation and modification shortly after impact. Importantly, numerous other mare-filled mascon basins on the Moon share the same topographic and tectonic characteristics as Crisium, suggesting that they, too, are underlain by deep-seated thrust faults that formed in a similar manner. [ABSTRACT FROM AUTHOR]

To increase the knowledge on the particulate matter of a wetland in Beijing, an experimental study on the concentration and composition of PM 10 and PM 2.5 was implemented in Beijing Olympic Forest Park from 2013 to 2014. This study analyzed the meteorological factors and deposition fluxes at different heights and in different periods in the wetlands. The results showed that the mean mass concentrations of PM 10 and PM 2.5 were the highest at 06:00–09:00 and the lowest at 15:00–18:00. And the annual concentration of PM 10 and PM 2.5 in the wetland followed the order of dry period (winter) > normal water period (spring and autumn) > wet period (summer), with the concentration in the dry period significantly higher than that in the normal water and wet periods. The chemical composition of PM 2.5 in the wetlands included NH 4 + , K + , Na + , Mg 2 + , SO 4 2 − , NO 3 − , and Cl − , which respectively accounted for 12.7%, 1.0%, 0.8%, 0.7%, 46.6%, 33.2%, and 5.1% of the average annual composition. The concentration of PM 10 and PM 2.5 in the wetlands had a significant positive correlation with relative humidity, a negative correlation with wind speed, and an insignificant negative correlation with temperature and radiation. The daily average dry deposition amount of PM 10 in the different periods followed the order of dry period > normal water period > wet period, and the daily average dry deposition amount of PM 2.5 in the different periods was dry period > wet period > normal water period. [ABSTRACT FROM AUTHOR]

In this study, PM 2.5 samples were collected at four heights (10 m, 40 m, 120 m and 220 m) at a meteorological tower in the daytime and nighttime during the heating season in Tianjin, China. The vertical variation and diurnal variability of the concentrations of PM 2.5 and main chemical compositions were analyzed in clear days and heavy pollution days. Generally, mass concentrations of PM 2.5 and the chemical compositions showed a decreasing trend with increasing height, while mass percentages of SO 4 2 − , NO 3 − and OC showed an increasing trend with increasing height. Concentrations of ion species and carbon compound in PM 2.5 samples in the daytime were higher than those collected at night, which was due to intense human activities and suitable meteorological condition in the daytime. The ratios of NO 3 − /SO 4 2 − and OC/EC were also considered, and we have observed that their levels on heavy pollution days were higher than those on clear days. In addition, source apportionments were identified quantitatively using the CMB-iteration model. The results indicated that contributions of secondary ion species increased with increasing height, while contributions of other pollutant sources decreased, and contributions of vehicle exhaust were relatively high on clear days. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare co-located real-time light scattering devices and equivalent gravimetric samplers in poultry and pig houses for PM 10 mass concentration, and to develop animal-specific calibration factors for light scattering samplers. These results will contribute to evaluate the comparability of different sampling instruments for PM 10 concentrations. Paired DustTrak light scattering device (DustTrak aerosol monitor, TSI, U.S.) and PM 10 gravimetric cyclone sampler were used for measuring PM 10 mass concentrations during 24 h periods (from noon to noon) inside animal houses. Sampling was conducted in 32 animal houses in the Netherlands, including broilers, broiler breeders, layers in floor and in aviary system, turkeys, piglets, growing-finishing pigs in traditional and low emission housing with dry and liquid feed, and sows in individual and group housing. A total of 119 pairs of 24 h measurements (55 for poultry and 64 for pigs) were recorded and analyzed using linear regression analysis. Deviations between samplers were calculated and discussed. In poultry, cyclone sampler and DustTrak data fitted well to a linear regression, with a regression coefficient equal to 0.41, an intercept of 0.16 mg m −3 and a correlation coefficient of 0.91 (excluding turkeys). Results in turkeys showed a regression coefficient equal to 1.1 (P = 0.49), an intercept of 0.06 mg m − 3 (P < 0.0001) and a correlation coefficient of 0.98. In pigs, we found a regression coefficient equal to 0.61, an intercept of 0.05 mg m −3 and a correlation coefficient of 0.84. Measured PM 10 concentrations using DustTraks were clearly underestimated (approx. by a factor 2) in both poultry and pig housing systems compared with cyclone pre-separators. Absolute, relative, and random deviations increased with concentration. DustTrak light scattering devices should be self-calibrated to investigate PM 10 mass concentrations accurately in animal houses. We recommend linear regression equations as animal-specific calibration factors for DustTraks instead of manufacturer calibration factors, especially in heavily dusty environments such as animal houses. [ABSTRACT FROM AUTHOR]

This study was performed to investigate the concentration and the health risk of heavy metals (HMs: Zn, Pb, Cd, Ni, Fe, Mn, Cr and Cu) in size-segregated airborne particulate matter (APM). APM samples were collected into 9 size fractions (> 9.0 μm, 5.8–9.0 μm, 4.7–5.8 μm, 3.3–4.7 μm, 2.1–3.3 μm, 1.1–2.1 μm, 0.7–1.1 μm, 0.4–0.7 μm, < 0.4 μm) by an 8 Stage Non-Viable Cascade Impactor in the campus of Hunan University in Changsha. And then 9 fractions of APM were analyzed for HMs by ICP–OES. The total size-segregated APM concentration in the campus of Hunan University ranged from 120.24 to 271.15 μg/m 3 , and the concentration of HMs in APM was in the range of 38.08–13955.14 ng/m 3 . The health risk of HMs in APM was evaluated by hazard quotient (HQ) and hazard index (HI) and the results showed that dermal contact and ingestion of APM were the major exposure pathways to human health. The HI values of Cd, Mn, Pb and Cr for children and Cd, Mn and Pb for adults exhibited to be higher than 1 indicating that a non-carcinogenic health effect existed in the APM of the campus of Hunan University. The carcinogenic risks of Cd, Ni and Cr were all bellow the safe value. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the influence of atmospheric fine particulate matter (PM 2.5 ) pollution on indoor environment. Time series of indoor and outdoor PM 2.5 mass concentrations in a naturally ventilated building were monitored continuously and simultaneously in winter in Beijing when haze-fog episodes happen frequently. Relationships between indoor and outdoor PM 2.5 mass concentrations were examined and discussed. Indoor and outdoor PM 2.5 mass concentrations showed close correlation (R 2 = 0.9104) when the windows are closed and there are no obvious indoor particle sources. The peak values of average indoor PM 2.5 mass concentrations appeared at night, which were 1.5 times higher than the minimum values in daytime and showed an increasing trend from Monday to Friday in workdays. The indoor/outdoor PM 2.5 mass concentrations ratios (I/O ratios) are closely correlated with outdoor wind speed and relative humidity. A prediction model was developed based on a method of mathematical statistics and it was applied to estimation of indoor PM 2.5 mass concentrations by using outdoor PM 2.5 mass concentrations and meteorological parameters as inputs. There is a good agreement between model results and the measured values with correlation coefficients of R 2 = 0.95. The findings can provide meaningful reference to further research on influence of atmospheric PM 2.5 on indoor environment and help further develop approaches to control outdoor originated indoor PM 2.5 in the haze-fog episodes. [ABSTRACT FROM AUTHOR]

With the economic development during the past thirty years, the atmospheric particulate matters over eastern China have reached high levels, causing serious environmental pollution and increased threat to public health. The in situ measurement of fine particulate matter (PM 2.5 ) mass concentration is currently widely employed even if this traditional approach has limitations with respect to wide-range coverage and spatial continuity. Satellite remote sensing provides a possibility to monitor continuously spatial coverage of atmospheric particulate matters. However, the conversion between particle mass concentration and remotely sensed optical parameters is still a big challenge. The existing correlation approaches, i.e. estimating aerosol optical depth (AOD) and surface PM 2.5 relationship based on statistics with limited samples, meet more and more limitations with respect to representativeness and applicability. In this paper, we developed a relationship between fine particle extinction and its volume, and thus established a multi-parameter remote sensing formula of dry PM 2.5 mass concentration near the ground. To test the method, we utilized AOD and fine mode fraction (FMF) provided by the MODerate resolution Imaging Spectroradiometer (MODIS), supplementing with planetary boundary layer height (PBLH) and relative humidity (RH) obtained from re-analysis data based on model simulation. The remote sensing results of dry PM 2.5 mass concentration near the ground over polluted regions of China from October to December 2013 showed that our method revealed well the spatial distribution of PM 2.5 in the study area and illustrated clearly the daily variation. The validation against 15 in situ stations showed good performance of the method formulas (mean values of 101 vs. 105 μg/m 3 for the average of three months of data) and suggested main errors caused by the input data which could be improved in the near future with the advance of satellite remote sensing. We also discussed uncertainty sources and possible improvements. [ABSTRACT FROM AUTHOR]

Both PM 2.5 mass concentration and its chemical composition are a great concern to human health. In this study, the concentrations of PM 2.5 and their metallic elements were measured to identify the characteristics and to trace sources at two different functional areas, a residential and a cement industrial area. The average PM 2.5 concentrations were not significantly different between the two sites, but their chemical compositions were clearly different. Crustal elements in PM 2.5 were significantly higher in the residential area, while the concentrations of metals typically emitted from anthropogenic sources were generally higher in the cement industrial area. Crustal elements often increased during spring in the residential area due to the blustery weather with high wind speeds; however, most metallic elements were enhanced during winter in the cement industrial area. Principal component analysis was used to trace the sources. Soil re-suspension, traffic-related sources, and asphalt concrete production were identified as the main sources of PM 2.5 in the residential area, while the cement industry, Ni–Cr plating industry, and other industrial activities were identified in the cement industrial area. [ABSTRACT FROM AUTHOR]

The first simultaneous aethalometer and solar radiometer measurements of black carbon (BC) mass concentration (surface-level) and aerosol optical, microphysical and radiative parameters (columnar) have been made during 2005–2011 over two contrasting experimental sites, one representing background rural environment (Sinhagad) and the other surrounded by urban environment (Pune) in the south-west India. The long-term diurnal cycle of BC aerosols over both sites exhibited a strong peak during daytime and a weaker plateau around evening–midnight hours, implying the influence of anthropogenic emissions as well as changes in planetary boundary layer (PBL). The multi-year seasonal mean variation in BC concentration shows the highest during winter and lowest during monsoon seasons, which is found to be inversely related to the variations in single scattering albedo (SSA). Moreover, the BC variations were found to be strongly associated with greater values of Angstrom exponent ( α ), indicating that the observed BC involves abundance of fine-mode aerosol fraction. The higher concentrations of BC during winter and lower concentrations during pre-monsoon over both Pune and Sinhagad are noticed to be closely linked with aerosol optical depth, revealing significant contribution of BC to the composite aerosol over both the regions. The columnar AOD and Angstrom exponent also showed relatively greater optical depth and α values during winter as compared to pre-monsoon season over both sites. [ABSTRACT FROM AUTHOR]

In this paper, we have used the Lie group of transformations and obtained the whole range of self-similar solutions to the problem of propagation of shock waves through a non-ideal, dusty gas. The conditions essential for the existence of similarity solutions for a strong shock are discussed. The problem of imploding (converging) shock wave is also worked out and the effects of the mass concentration of the dust particles, ratio of the density of solid particles to that of initial density of the medium, the relative specific heat and the effect of the non-ideal parameter, on the shock formation has been studied in detail. [ABSTRACT FROM AUTHOR]

An intensive sampling campaign was conducted in the autumn of 2012 to study the size distribution of inorganic ions and ion deposition at an offshore site of Yangtze River Delta region (YRD), China. Particles in <0.43, 0.43-0.65, 0.65-1.1, 1.1-2.1, 2.1-3.3, 3.3-4.7, 4.7-5.8, 5.8-9.0 and 9.0-10.0 µm were collected and analyzed by ion chromatography for NH4+, Na+, Mg2+, K+, Ca2+, F-, Cl-, NO3- and SO42-. The average mass concentrations in the nine particle sizes ranged from 13.1 to 38.7 µ g m-3, accounting for 5.5%-16.8% of the total mass. Concentrations exhibit bi-modal distribution, peaking at 0.65-1.1 µm and 3.3-4.7 µm. PM1.1, PM2.1 and PM2.1-10 account for 41%, 56% and 44% of PM10 implying the dominance of finer particles. Different ions hold different size distribution patterns. The concentrations of NO3-, SO42-, NH4+, K+ and Ca2+ exhibit the highest values when compared to literature values indicating the serious air pollution situation in YRD. A haze-precipitation-fog transition course is captured. The precipitation can decrease all the particles in the nine sizes by 20%-62% and the fog formation process can promote the particles' accumulation, with their mass concentrations increasing by 26%-232% except for those in 5.8-9.0 µm and 9.0-10 µm. Mass percentages of SO42-, NO3- and NH4+ exhibit decreases during precipitation and increases during fog formation course. The anion to cation ratios are lower than 1.0 indicating the anion deficiency and they exhibit significant negative relationship with the particle diameter. The Cl-dep (%) is higher for particles larger than 0.65 µm, increasing from 1.3% to 61% with size added. Sea salt only accounts for 0.12%-2.1% of PM10. The ratios of nss-SO42-/NO3- decrease with increasing particle size, from 1.68 to 0.69, and are well fit as linear form (r = -0.74, p = 0.02). It indicates that stationary sources make more contributions to smaller particles and vehicle emission is more important for larger particles. The dry deposition fluxes for F-, Cl-, NO3- and SO42- are 3.10, 0.59, 22.99 and 17.04 mg/(m²d). They exhibit multi-linear correlation with corresponding ion concentrations and the coefficients are higher for coarse particles. More researches are needed to obtain the distribution, transportation and deposition characteristic of ions at Chinese coastal area. [ABSTRACT FROM AUTHOR]

Temporal variability (November'09–March'10) in the mass concentrations of PM2.5, mineral dust, organic carbon and elemental carbon (OC and EC), water-soluble organic carbon (WSOC) and inorganic species (WSIS) has been studied in the atmospheric outflow to the Bay of Bengal from a sampling site [Kharagpur: 22.02°N, 87.11°E] in the Indo-Gangetic Plain (IGP). Based on diagnostic ratios of carbonaceous species [OC/EC≈7.0±2.2, WSOC/OC≈0.52±0.16, and K+/EC≈0.48±0.17], we document dominant impact from biomass burning emissions (wood-fuel and post-harvest agricultural-waste burning) in the IGP-outflow. Relatively high concentration of sulphate (SO4 2− ≈6.9–25.3μgm−3; SO4 2−/ΣWSIS=45–77%) and characteristic ratios of nss-SO4 2−/EC (3.9±2.1) and nss-SO4 2−/OC (0.61±0.46) provide information on absorption/scattering properties of aerosols. Based on quantitative assessment of individual components of PM2.5, we document aerosol organic carbon-to-organic mass (OC to OM) conversion factor centring at 1.5±0.2 (range: 1.3–2.7) in the atmospheric outflow from IGP. The aerosol composition over the Bay of Bengal shows striking similarity with the diagnostic ratios documented for the IGP-outflow. Relatively high conversion factor for assessing the mass of organic aerosols over the Bay of Bengal (1.1–3.7) provides evidence for their oxidation during long-range atmospheric transport. [ABSTRACT FROM AUTHOR]

Abstract: The present study describes the effectiveness of different flow control methods applied to a serpentine intake. Due to the geometry of the duct and diffusing nature of flow, the duct performs poorly as an intake, delivering low pressure and distorted air to the compressor. The problem can be alleviated by employing flow control on the duct. In this study, two types of flow control, namely steady vortex generator jets and boundary layer suction, have been applied and detailed measurements carried out. The performance of the duct has been evaluated with respect to static pressure recovery, total pressure loss and circumferential distortion at the exit. The amount of mass flow required to be added or removed for each method is also considered. It was found that the application of suction showed a greater improvement in total pressure recovery and reduction in circumferential distortion intensity compared to vortex generator jets. A combination of suction and vortex generator jets showed an improved performance compared to application of either. The improvements are attributed to reduction in flow separation region due to suction and a decrease in the effect of secondary flow due to vortex generator jets. [Copyright &y& Elsevier]

Abstract: We consider a particular effect which can be expected in scenarios of deviations from special relativity induced by Planckian physics: the loss of additivity in the total energy of a system of particles. We argue about the necessity to introduce a length scale to control the effects of non-additivity for macroscopic objects and consider white dwarfs as an appropriate laboratory to test this kind of new physics. We study the sensitivity of the mass-radius relation of the Chandrasekhar model to these corrections by comparing the output of a simple phenomenological model to observational data of white dwarfs. [Copyright &y& Elsevier]

Regular measurements of Black Carbon (BC) aerosol mass concentration have been carried out since March 2011 at a tropical location (12.81°N, 80.03°E) adjoining the mega city, Chennai, on the east coast of India for the first time. As this region is influenced by both the South West and North East monsoons, the BC observations at this site assume importance in understanding the overall BC distribution over India. The data collected until August 2012 has been examined for the general and regionally distinctive features. Spectral absorption characteristics reveal that the BC is mainly from fossil fuel based emissions. The BC concentration shows significant diurnal variation only in the North East monsoon and winter seasons with night time concentration considerably higher than the day time concentration. In the other seasons the day–night contrast in BC is not significant. Seasonal variation is rather subdued with a broad maximum during the Northeast monsoon and winter months and a minimum during the southwest monsoon months. The observed diurnal and seasonal variations are examined in the light of local Atmospheric Boundary Layer dynamics and long range transport. For the first time, an inverse relationship has been established between BC and ABL height on a quantitative basis. A distinctive feature of the region is that in all the seasons transport pathways have long continental overpasses which could lead to the suppressed seasonal variation. It is found that the BC over this region shows distinct diurnal and seasonal features compared to those reported for other coastal and inland regions in India. [ABSTRACT FROM AUTHOR]

Measurements of aerosol optical depth (AOD), mass concentrations of black carbon (M B ) and composite aerosols (M T ) in the marine atmospheric boundary layer (MABL) were made during onward [Dec 2007 to Jan 2008; Northern Hemispheric (NH) winter] and return (Mar–Apr 2008; NH spring) legs of the trans-continental cruise of 27th Indian Scientific Expedition to Antarctica (ISEA) during International Polar Year of 2007–2008. Large latitudinal gradients are seen; with AOD decreasing from coastal India (AOD~0.45) to coastal Antarctica (AOD~0.04) during NH winter. The measurements also evidenced a strong seasonality of AOD over all regions, with a decrease of the values and gradient in NH spring. BC concentration in the MABL decreases exponentially from 3800ngm−3 (over 10°N) to 624ngm−3 near equator and much lower values (<100ngm−3) over southern oceanic region. Seasonality in the latitudinal gradients of AOD, M B and M T exists over regions north of 20°S. Multi campaign [Pilot Expedition to Southern Ocean (2004), Special Expedition to Larsemann Hills (2007) and Tropical Indian Ocean cruise (2010)] analysis over these oceanic regions showed that the pattern over the regions (south of 20°S) remained the same. Seasonality of AOD exists over Atlantic Ocean as well. Temporal variation of AOD at different latitudes derived from AERONET data also showed marked seasonality and latitudinal variation in northern hemisphere than in southern Hemisphere. Satellite retrieved AOD showed good correlation with the ship borne measurements; while GOCART retrieved AOD underestimates but gives a measure of the spatial variations. [ABSTRACT FROM AUTHOR]

This paper experimentally investigates the particle concentration distribution and deposition in three-dimensional 90° bends considering three potential influencing factors: inlet mass concentration C m , Reynolds number Re and wall material. Particle penetrations were found to decrease moderately within 11% with the increase of C m under current conditions, but deposition velocity would increase by 1.29–2.87 times. The inlet particle concentration will not affect the outlet concentration distribution and particle penetration for the particles of St=5.15×10−4. For larger particles, however, higher C m , St and Re cause higher concentration near the outer wall of bend outlet, lower concentration near the inner wall and even ‘particle free zone’. For the outlet concentration distribution, apexes and concave points are observed, which may be formed by the rebounding particles. Furthermore, concentration polarization factor is introduced to analyze the outlet nonuniformity. Accordingly, Re is found to be a higher weighting factor compared with C m . Compared to penetration, deposition velocity is more sensitive to wall materials, for example, with an increase factor up to 1.45. Furthermore, a rough estimation method and an empirical model are suggested to establish the correlation among dimensionless outlet concentration, St and ‘particle free zone’. [ABSTRACT FROM AUTHOR]

Abstract: This paper proposes the use of an optimal design method, based on multi-island genetic algorithm (MIGA), for the design of a ballistic single-stage sub-orbit rocket vehicle employing a hybrid rocket motor. The mathematical model of sub-orbit hybrid rocket system and a 2 degree of freedom (DOF) trajectory simulation are developed as part of this investigation. The star port grain rocket vehicles with 98% and 90% hydrogen peroxide (H2O2, diluted with water, for short “HP”)/hydroxyl-terminated polybutadiene (HTPB) propellant combination, and the 90% HP/HTPB propellant combination rocket vehicles with four different gain types, including star port grain, single circle port grain, wheel port grain and multi-tube grain, are optimized respectively to carry out the parametric analysis on the relations of propellant combinations and design variables with the performances of the rocket vehicles. The final results show that the increase of oxidizer mass concentration has considerable contributions to reduce the lift-off mass of the rocket vehicles, while it has almost no effects on the initial grain shape parameters except the initial grain diameter. For the four initial design parameters, the value of initial chamber pressure, initial mixture ratio and nozzle expansion ratio have less effect on the rocket performances compared to the initial value of thrust, when the initial grain shape parameters are constant. Among the four type hybrid rockets, the one with a multi-tube grain performs best, because it has the largest burning perimeter length. [Copyright &y& Elsevier]