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Removing submicron particles in the size range from 0.1 to 1.0 µm from gas streams is difficult because they cannot be efficiently captured neither through inertial separation nor by diffusion utilized in air pollution control devices. Electrostatic agglomeration is an effective and practical method for improving the removal efficiency of fine particulate matters. For optimizing the performance of electrostatic agglomerators, in addition to the intensity and frequency of an alternating electric field and the particle residence time, an electrostatic aerosol particle agglomerator was designed and established to experimentally evaluate the influence of particle charges on its performance in this study. The results demonstrate that the performance of the electrostatic aerosol agglomerator can be greatly improved in terms of increasing the particle charges from 9 to 19 (e−/particle). Combined with the low frequency of an AC electric field, the agglomeration efficiency can be further enhanced. The highest agglomeration efficiency of 40.2% is achieved in the submicron size range at AC frequency of 45 Hz. Furthermore, the oscillating distance (cm/Hz) is proposed and estimated for correlating the agglomeration efficiency under various testing conditions. It was found that the agglomeration efficiency can be described by a simple power-law equation using this parameter.

Electrospray-differential mobility analysis coupled with aerosol particle mass analysis (ES-DMA/APM) was demonstrated for the development of a metal–organic framework (MOF) nanocarrier system. A successful quantification of ibuprofen loading in UiO-66-NH2 (i.e., the representative drug molecule and MOF, respectively) achieved based on the aerosol particle mass of MOF measured by ES-DMA/APM (≈55 mg of ibuprofen/g of UiO-66-NH2). The structural stability of UiO-66-NH2 versus ibuprofen release was successfully quantified over a 7-day period in an acidic phosphate buffer solution. The methodology provides a proof-of-concept scheme for controlled release studies of different types of active pharmaceutical ingredients from a variety of MOF-based nanocarrier systems.

Traffic emission is responsible for most small-sized particulate matter (PM) air pollution in urban areas. Several recent studies have indicated that traffic-related PM may aggravate kidney disease. Furthermore, exposure to particulate air pollution may be related to the risk of chronic kidney disease (CKD). However, the underlying molecular mechanisms have not been adequately addressed. In the present study, we studied the mechanisms of renal damage that might be associated with exposure to PM. In a real world of whole-body exposure to traffic-related PM model for 3-6 months, PM in urban ambient air can affect kidney function and induce autophagy, endoplasmic reticulum (ER) stress and apoptosis in kidney tissues. Exposure to traffic-related diesel particulate matter (DPM) led to a reduction in cell viability in human kidney tubular epithelial cells HK-2. DPM increased mitochondrial reactive oxygen species (ROS) and decreased the mitochondrial membrane potential. Furthermore, DPM induced ER stress and activated the unfolded protein response (UPR) pathway. Eventually, DPM exposure induced caspase pathways and triggered apoptosis. In addition, DPM induced autophagy through the inhibition of the Akt/mTOR pathway. Autophagy inhibition resulted in significantly increased cytotoxicity and apoptosis. These findings suggest that air pollution in urban areas may cause nephrotoxicity and autophagy as a protective role in PM-induced cytotoxicity.

Virtual impactors can be used as aerosol concentrators as well as particle size classifiers. The flow field and particle trajectory inside a linear slit-type virtual impactor were investigated using a commercial computational fluid dynamics software package. Effects of flow and slit geometry, including the inlet flow (Qin), the ratio of minor to total flow (r), and the configuration of the taper-lip slit nozzle and the collection slit nozzle, were studied. A new modified Stokes number (Stkc) for the virtual impactor was proposed to predict the d50 at different r values. Stkc,500.5 was found to be retained at approximately 0.9 under different Qin or r values, and it can be considered the characteristic performance parameter for the slit virtual impactor. The numerical simulation results show that the particle loss starts increasing when Stkc0.5 is larger than 2.0 due to a particle-crossing phenomenon. The range of the maximum concentration factor (CFmax) is influenced by the particle-crossing phenomenon. An expression was also developed to predict the size range of particles with the maximum CF under different inlet flow rates. Regarding the geometrical configuration, the arc-lip nozzle could postpone particle-crossing and lessen the internal losses of coarse particles, whereas it increased particle losses near d50. However, the divergent collection slit nozzle could effectively decrease particle losses on the wall of the nozzle without this side effect. The designing guidelines of a linear-slit virtual impactor are briefly summarized based on these findings.

A custom-built steam-based aerosol collector (SBAC) was developed to improve the detection limits in aerosol chemical analysis. The SBAC was coupled with wet chemical analytical instruments to characterize the chemical composition of ambient particulate matter with high-time resolution. The particulate matter was mixed with a jet of steam and formed large droplets because of the supersaturation condition in the cooling chamber. The enlarged droplets were subsequently collected using an inertial aerosol separator and delivered to selected instruments for chemical analysis. Experiments were subsequently conducted to evaluate our custom-built SBAC under various sampling flow rates. In particular, particle growth and particle collection efficiency experiments were conducted, and the SBAC was compared with a filter-based sampler. Sample solutions were collected, extracted, and analyzed to determine the influence of sampling flow rate, particle size, and aerosol chemical concentration on the SBAC's collection efficiency. The SBAC was found to provide data with a higher time resolution, to exhibit an improved detection limit, and to effectively perform aerosol chemical analysis compared with the filter-based samplers, although the effect of flow rate on SBAC performance is complicated and further experiments on this aspect are warranted. This paper contributes to the literature by providing guidelines for designing a SBAC for aerosol chemical analysis.

Vehicle emissions are an important source of particulate matter (PM) in urban areas and have well-known adverse health effects on human health. Oxidative potential (OP) is used as a quantification metric for indexing PM toxicity. In this study, by using a liquid spot sampler (LSS) and the dithiothreitol (DTT) assay, the diurnal OP variation was assessed at a ground-level urban monitoring station. Besides, since the monitoring station was adjacent to the main road, the correlation between OP and traffic volume was also evaluated. PM components, including metals, water-soluble inorganic aerosols (WSIAs), black carbon (BC), and polycyclic aromatic hydrocarbons (PAHs), were also simultaneously monitored. The daytime and evening mean ± std volume-normalized OP (OPv) were 0.46 ± 0.27 and 0.48 ± 0.26 nmol/min/m3, and exhibited good correlations with PM1.0 and BC; however, these concentrations were only weakly correlated with mass-normalized OP (OPm). The mean ± std OPm was higher in the daytime (41.3 ± 13.8 pmol/min/μg) than in the evening (36.1 ± 11.5 pmol/min/μg). According to the PMF analysis, traffic emissions dominated the diurnal OP contribution. Organic matter and individual metals associated with non-exhaust traffic emissions, such as Mn, Fe, and Cu, contributed substantially to OP. Diurnal variations of PAH concentrations suggest that photochemical reactions could enhance OP, highlighting the importance of atmospheric aging on PM toxicity.

Exposure to road dust particulate matter (PM) causes adverse health impacts on the human airway. However, the effects of road dust on the upper airway epithelium in humans remain unclear. We investigated the involvement of the epidermal growth factor receptor (EGFR) after PM with an aerodynamic diameter of2.5 μm (PM

Cigarette smoke (CS) has been reported to induce oxidative stress and inflammatory process in the lungs. However, the role of human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) in the regulation of pulmonary inflammation remains unclear. The objective of this study is to investigate the effects of hUC-MSCs on lung inflammation in the acute CS-induced pulmonary inflammation animal model. Eight-week-old male C57BL/6 mice were intravenously administered 3 × 106, 1 × 107, and 3 × 107 cells/kg of hUC-MSCs as well as normal saline alone (control) after 3 days of CS exposure. Mice exposed to high-efficiency particulate air (HEPA)-filtered room air served as the CS control group. High-dose (3 × 107 cells/kg) hUC-MSC administration significantly decreased tumor necrosis factor (TNF)-α in the bronchoalveolar lavage fluid (BALF) of CS-exposed mice (p < 0.05). The chemokine (CXC motif) ligand 1/keratinocyte chemoattractant (CXCL1/KC) in BALF were significantly reduced by low-dose (3 × 106 cells/kg) and high-dose (3 × 107 cells/kg) hUC-MSC (p < 0.05). Medium-dose hUC-MSC administration decreased interleukin (IL)-1β in lung of mice, and TNF-α and caspase-3 were decreased in the lung of CS-exposed mice by medium- and high-dose MSC (p < 0.05). Low-dose hUC-MSCs significantly elevated serum CXCL1/KC and IL-1β in CS-exposed mice (p < 0.05). Our results suggest that high-dose hUC-MSCs reduced pulmonary inflammation and had antiapoptotic effects in acute pulmonary inflammation.

The aim of this study is to assess the offshore wind and solar power and to determine whether the future power supply in Taiwan will be stable. The estimated annual offshore wind and solar power generation for 2030 are 11343 GWh and 11367 GWh, respectively. Based on these results, it appears that the annual power supply can easily help balance the total power demand. However, the power demand is high during the summer peak months, and power generation may be insufficient during peak summer hours by 2030. Specifically, in 2024, the peak hourly percent reserve margin (PRM) in summer will be negative (-0.9%). If the installation of offshore wind turbines and solar panels is delayed, then the problem of insufficiency will be even more severe. However, if the offshore wind and solar photovoltaic projects are completed on schedule, and the first, second, and third nuclear power plants (NPPs) extend their service to 2030, then the hourly PRM could reach 15% during the summer peak hours from 2025 to 2030 and 5–11% in the other years. Moreover, if the fourth NPP opens, then the estimated summer peak hourly PRM would increase by 6–7%.

This study investigated the effects of pollution emissions on the bioreactivity of PM2.5 during Asian dust periods. PM2.5 during the sampling period were 104.2 and 85.7 μg m−3 in Xi'an and Beijing, respectively, whereas PM2.5 which originated from the Tengger Desert was collected (dust background). Pollution conditions were classified as non-dust days, pollution episode (PE), dust storm (DS)-1, and DS-2 periods. We observed a significant decrease in cell viability and an increase in LDH that occurred in A549 cells after exposure to PM2.5 during a PE and DS-1 in Xi'an and Beijing compared to Tengger Desert PM2.5. Positive matrix factorization was used to identify pollution emission sources. PM2.5 from biomass and industrial sources contributed to alterations in cell viability and LDH in Xi'an, whereas vehicle emissions contributed to LDH in Beijing. OC, EC, Cl−, K+, Mg2+, Ca, Ti, Mn, Fe, Zn, and Pb were correlated with cell viability and LDH for industrial emissions in Xi'an during DS. OC, EC, SO42−, S, Ti, Mn, and Fe were correlated with LDH for vehicle emissions in Beijing during DS. In conclusion, the dust may carry pollutants on its surface to downwind areas, leading to increased risks of particle toxicity.

Source-apportioned particle concentrations are necessary to properly evaluate the health impacts of air pollution. In this study, a measurement station was established at an urban roadside in northern Taiwan to the investigate lung deposited surface area (LDSA) concentration, a relevant metric for the adverse health effects of aerosol exposure, along with PM

We investigated the effects of nickel oxide nanoparticles (NiONPs) on the pulmonary inflammopathology. NiONPs were intratracheally installed into mice, and lung injury and inflammation were evaluated between 1 and 28 days. NiONPs caused significant increases in LDH, total protein, and IL-6 and a decrease in IL-10 in the BALF and increases in 8-OHdG and caspase-3 in lung tissues at 24 h. Airway inflammation was present in a dose-dependent manner from the upper to lower airways at 24 h of exposure as analyzed by SPECT. Lung parenchyma inflammation and small airway inflammation were observed by CT after NiONP exposure. 8-OHdG in lung tissues had increased with formation of fibrosis at 28 days. Focal adhesion was the most important pathways identified at 24 h as determined by protemics, whereas glutathione metabolism was the most important identified at 28 days. Our results demonstrated the pulmonary inflammopathology caused by NiONPs based on image-to-biochemical approaches.

The objective of this study was to identify hazards that occur due to surgical practices and assess exposure to surgical smoke. We investigated nine surgical specialties in their corresponding operating rooms (ORs) for on-line measurements of pollutants and off-line determination of PAHs. Surgery for the face and dentistry generated the smallest particle size with a GMD of 23.3 nm. Also, the highest levels of the lung deposition surface area (5.8 ± 6.8 μm2/cm3), particulate matter of

Sleep disorders may pose a risk to workers in the workplace. We aimed to investigate the associations between metal fume fine particulate matter (PM2.5) and sleep quality in workers. We assessed the effects of personal exposure to metal fume PM2.5 on lung functions, urinary biomarkers, and sleep quality in shipyard welding workers. In total, 96 welding workers and 54 office workers were recruited in the present study; office workers were exposed to 82.1 ± 94.1 μg/m3 PM2.5 and welding workers were exposed to 2166.5 ± 3149.1 μg/m3. Welding workers had significantly lower levels of FEV25-75 than office workers (p

We demonstrate a new, facile gas-phase electrostatic approach to successfully quantify equivalent surface area of graphene oxide (GO) colloid on a number basis. Mobility diameter (dp,m)-based distribution and the corresponding equivalent surface area (SA) of GO colloids (i.e., with different lateral aspect ratios) were able to be identified by electrospray-differential mobility analysis (ES-DMA) coupled to a condensation particle counter (CPC) and an aerosol surface area analyzer (ASAA). A correlation of SA ∝ dp,m2.0 was established using the ES-DMA-CPC/ASAA, which is consistent with the observation by the 2-dimensional image analysis of size-selected GOs. An ultrafast surface area measurement of GO colloid was achieved via a direct coupling of ES with a combination of ASAA and CPC (i.e., measurement time was 2 min per sample; without size classification). The measured equivalent surface area of GO was ∼202 ± 7 m2 g–1, which is comparable to Brunauer–Emmett–Teller (BET) surface area, ∼240 ± 59 m2 g–1. The...

Inhaled zinc oxide nanoparticles (ZnONPs) have high deposition rates in the alveolar region of the lungs; however, the adverse health effects of ZnONPs on the respiratory system are unclear. Herein, pathobiological responses of the respiratory system of mice that received intratracheal administration of ZnONPs were investigated by a combination of molecular and imaging (SPECT and CT) approaches. Also, normal BEAS-2B and adenocarcinoma A549 cells were used to confirm the results in mice. First, female BALB/c mice were administrated a series of doses of 20-nm ZnONPs and were compared to the phosphate-buffered saline control for 24-h and 28-day follow-up observations. Field emission-scanning electron microscopy and an energy-dispersive X-ray microanalysis were first used to characterize ZnONPs. After 24h, instilled ZnONPs had caused significant increases in lactic dehydrogenase (LDH) in bronchoalveolar lavage fluid (BALF) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), caspase-3, and the p63 tumor marker in lung tissues (p

The direct air-liquid interface (ALI) in vitro exposure method are used for high-throughput screening of nanoparticle toxicity, due to the relatively low capital required and the low cost of labor compared to animal and in vivo experiments. In this study, a new ALI exposure chamber using an electrostatic precipitator (ESP–ALI) was designed to improve the nano- and submicron-sized particle collection efficiency on the air-liquid exposure interface. Particle penetration tests were performed to characterize the performance under different operating conditions. The effects of different geometric dimensions and operating conditions were explored, and the similarity-scaling process was applied to reveal the hidden effects underlying the experimental data. The penetration results show that the developed electrostatic precipitator is able to efficiently collect particles with a size of up to 300 nm under a DC electric field of 5.0 kV/cm and at a flow rate of up to 1.5 lpm. The electrospray charging technique was also tested with this ESP–ALI system and proved to enhance the ALI collection efficiency without ozone generation. In addition, the particles collected on the exposure interface are uniformly distributed under various operating conditions, as supported by consistent dimensionless precipitation densities.

The Lulin Atmospheric Background Station (LABS, 23.47 deg. N 120.87 deg. E, 2862 m ASL) in Central Taiwan was constructed in 2006 and is the only high-altitude background station in the western Pacific region for studying the influence of continental outflow. In this study, extensive optical properties of aerosols, including the aerosol light scattering coefficient [Sigma(sub s)] and light absorption coefficient [Sigma(sub a)], were collected from 2013 to 2014. The intensive optical properties, including mass scattering efficiency [Sigma(sub s)], mass absorption efficiency [Sigma(sub a)] single scattering albedo (Omega), scattering Angstrom exponent (A), and backscattering fraction (b), were determined and investigated, and the distinct seasonal cycle was observed. The value of [Alpha(sub a)] began to increase in January and reached a maximum in April; the mean in spring was 5.89 m(exp. 2) g(exp. -1) with a standard deviation (SD) of 4.54 m(exp. 2) g(exp. -1) and a 4.48 m(exp. 2) g(exp. -1) interquartile range (IQR: 2.95-7.43 m(exp. 2) g(exp. -1). The trend was similar in [Sigma(sub a)], with a maximum in March and a monthly mean of 0.84 m(exp. 2) g(exp. -1). The peak values of Omega (Mean = 0.92, SD = 0.03, IQR: 0.90 - 0.93) and A (Mean = 2.22, SD = 0.61, IQR: 2.12 = 2.47) occurred in autumn. These annual patterns of optical properties were associated with different long-range transport patterns of air pollutants such as biomass burning (BB) aerosol in spring and potential anthropogenic emissions in autumn. The optical measurements performed at LABS during spring in 2013 were compared with those simultaneously performed at the Doi Ang Kang Meteorology Station, Chiang Mai Province, Thailand (DAK, 19.93 deg. N, 99.05 deg. E, 1536 m a.s.l.), which is located in the Southeast Asia BB source region. Furthermore, the relationships among [Sigma(sub s)], [Sigma(sub a)], and (b) were used to characterize the potential aerosol types transported to LABS during different seasons, and the data were inspected according to the HYSPLIT 5-day backward trajectories, which differentiate between different regions of air mass origin.

A quantitative study of the stability of silver nanoparticles (AgNPs) conjugated with thiolated polyethylene glycol (SH-PEG) was conducted using gas-phase ion-mobility and mass analyses. The extents of aggregation and surface dissolution of AgNPs, as well as the amount of SH-PEG adsorption and desorption, were able to be characterized simultaneously for the kinetic study. The results show that the SH-PEG with a molecular mass of 6 kg/mol (SH-PEG6K) was able to adsorb to the surface of AgNP to form PEG6K-HS-AgNP conjugates, with the maximum surface adsorbate density of ∼0.10 nm(-2). The equilibrium binding constant for SH-PEG6K on AgNPs was calculated as ∼(4.4 ± 0.9) × 10(5) L/mol, suggesting a strong affinity due to thiol bonding to the AgNP surface. The formation of SH-PEG6K corona prevented PEG6K-HS-AgNP conjugates from aggregation under the acidic environment (pH 1.5), but dissolution of core AgNPs occurred following a first-order reaction. The rate constant of Ag dissolution from PEG6K-HS-AgNP was independent of the starting surface packing density of SH-PEG6K on AgNP (σ0), indicating that the interactions of H(+) with core AgNP were not interfered by the presence of SH-PEG6K corona. The surface packing density of SH-PEG6K decreased simultaneously following a first-order reaction, and the desorption rate constant of SH-PEG6K from the conjugates was proportional to σ0. Our work presents the first quantitative study to illustrate the complex mechanism that involves simultaneous aggregation and dissolution of core AgNPs in combination with adsorption and desorption of SH-PEG. This work also provides a prototype method of coupled experimental scheme to quantify the change of particle mass versus the corresponding surface density of functional molecular species on nanoparticles.

A hygroscopic tandem differential mobility analyzer (H-TDMA) and a hygroscopic coupled DMA and aerosol particle mass (H-DMA-APM) were coupled to examine aqueous film formation and the deliquescence behavior of inorganic nanoparticles. The two systems complement each other because H-DMA-APM measures mass change, while H-TDMA measures mobility diameter (volume) change of nanoparticles upon water uptake. The former mass change was, in particular, more capable to discern minute particle phase changes than the latter size change at moderate RHs. The mass and diameter changes were used to derive the particle effective density for evaluation of aqueous film formation on the nanoparticle surface before and after deliquescence transition. The measurements further showed that approximately 3–5 and 12–20 monolayer equivalents of water molecules formed on the respective surface of 50- and 100-nm inorganic aerosols (ammonium sulfate and sodium chloride) before deliquescence relative humidity (DRH). These findi...

A miniature cyclone with four inlets was designed and experimentally calibrated in this study as a size-selective inlet for compact/miniature sensors monitoring ultrafine particles (UFPs). The development of compact/miniature UFP sensors stemmed from the concern for adverse health effects resulting from ultrafine particles, reported by recent epidemiological studies. The performance of these sensors was often interfered by the presence of large particles in sampling stream. Miniature cyclones with multiple inlets can also minimize the potential issue of directional aerosol sampling, encountered in single-inlet cyclones. The pressure drop and particle cut-off performance of this quadru-inlet cyclone were experimentally characterized at various aerosol flowrates. Compared with mini-cyclones developed by Hsiao, Chen, and Son (2009) it is found that the prototype has smaller cutoff particle size and lower pressure drop when operated at the same aerosol flowrate. The linear relationship between the dimensionless cutoff particle size ( i . e . , C 0 . 5 d 50 D C ) and the annular flow Reynolds number (Reann), reported for single-inlet cyclones, was also observed for the studied quadru-inlet cyclone. Semi-empirical models were further proposed to calculate the pressure drop and cutoff particle sizes of mini-cyclones with only one-, two- and four inlets opened. The proposed models may serve as the guideline for the future design of mini- cyclones with multiple inlets.

A cyclone׳s performance can be optimized by changing its configuration, which is a very challenging task that depends on critical performance indicators. In this work, a comprehensive overview of the effects of a cyclone׳s longitudinal and radial dimensional ratios (including a/Dc, b/Dc, De/Dc, S/Dc, h/Dc, H/Dc, B/Dc) on its cutoff size, pressure drop, as well as the steepness of the sampling curve, was briefly reviewed. In addition, systematic experimental examinations were conducted to investigate different effects of geometric configurations on cyclone performance, and the optimal ranges for the geometric dimensional ratios were proposed. The results were analyzed according to four cyclone geometric components: the overall cyclone body, the cyclone contraction cone, the vortex finder (V.F.), and the inlet, and were compared to the observations reported in the literature. It was found that the effect of the overall cyclone body height (H) is closely related to the natural vortex length (Lv). The optimal H/Dc value based on the compromise between small dimensionless cutoff size ( d 50 ˜ ) and dimensionless pressure drop (ΔH) is around 5.5–7.0, which is slightly larger than the traditional Stairmand design. A cyclone with a short and wide cone would have a steeper cutoff curve and larger optimal H/Dc value than one with a long and sharp cone. Although a cyclone with cone results in higher collection efficiency, the slope of the efficiency curve is less steep than one without cone. On the other hand, both the collection efficiency and sharpness of the collection curve of a cyclone could be improved by reducing the outlet diameter and using an inlet with higher aspect ratio. The d 50 ˜ can be double and ΔH can be reduce 70% by varying the De/Dc from 0.28 to 0.71, while the effect of the inlet aspect ratio (a/b) is relatively insignificant.

Oil-coated particles are often encountered in the ambient and industrial working environments. However, experimental investigations have rarely been carried out on the loading behavior of filters loaded with oil-coated particles. In this study, the effects of the overall particle size, oil volume percentage, filter material, and surface tension and viscosity of the coating oils on the filter loading characteristics were examined. It was found that the general oil-coated particle loading behavior of filters transitions from that of solid-only particles to that of oil-only particles as the liquid volume percentage in the test particles increases. The typical transition trend of oil-coated particle loading curves is believed to be due to an increase in the fluidity of deposited oil-coated particles as the liquid percentage increases. It is further observed that, when the liquid volume percentage in coated particles is less than 50%, the filter loading behavior is dominated by the effect of the liquid surface tension and the filter pressure drop is largely due to the solid core of coated particles. Both the surface tension and viscosity of coating liquid influence the filter loading behavior when the liquid percentage in coated particles is higher than 50%.

This study aimed to simulate the transport of biomass burning (BB) aerosol originating from Southeast Asia (SEA) during the Dongsha Experiment conducted from March 2010 to April 2010. Transport pathways were reanalyzed and steering flow in the mid-latitude areas and anticyclones in low-latitude areas were found to control the transport of BB plume after it was injected to a high atmosphere. For the 12 simulated and observed events at Mt. Lulin (2862 m MSL; 23°28′07″ N, 120°52′25″ E), the 72 h backward trajectories were all tracked back to southern China and northern Indochina, which were the locations of the largest BB fire activities in SEA. Chemical evolutions of BB pollutants along the moving trajectories showed that organic matter was always the dominant component in PM2.5, consistent with the observations at both near-source regions and Mt. Lulin. For nitrogen species, nearly all NOx molecules oxidized into HNO3, NO3−, PAN, and PANX in fires or near fires. The synchronic consumption of NOx, SO2, and NH3 explained the production of the major components of inorganic salts. In the moving BB plume, sulfate concentration increased with decreased nitrate concentration. Ratios of ammonium to PM2.5 and elemental carbon to PM2.5 remained nearly constant because additional sources were lacking.

Air pollution might have a great impact on pulmonary health, but biological evidence in response to particulate matter less than 2.5 μm in size (PM2.5) has been lacking. Physicochemical characterization of haze PM2.5 collected from Beijing, Xian and Hong Kong was performed. Biological pathways were identified by proteomic profiling in mouse lungs, suggesting that WNT/β-catenin is important in the response to haze PM2.5. Suppression of β-catenin levels, activation of caspase-3 and alveolar destruction, as well as IL-6, TNF-α and IFN-γ production, were observed in the lungs. The inhibition of β-catenin, TCF4 and cyclin D1 was observed in vitro in response to haze PM2.5. The inhibition of WNT/β-catenin signaling, apoptosis-related results (caspase-3 and alveolar destruction), and inflammation, particularly including caspase-3 and alveolar destruction, were more highly associated with polycyclic aromatic hydrocarbons in haze PM2.5. In conclusion, decreased WNT/β-catenin expression modulated by haze PM2.5 could be involved in alveolar destruction and inflammation during haze episodes.

Chronic obstructive pulmonary disease(COPD) is characterized by enhanced chronic inflammation in the airways, lung parenchyma, and circulation. We investigated whether SUV39H1, a histone methyltransferase, is causatively implicated in the abnormal inflammation observed in COPD. The SUV39H1 and H3K9me3 levels were reduced in peripheral blood mononuclear cells(PBMCs), primary human small airway epithelial cells(HSAEpCs) and lung tissues from COPD patients, which were correlated with poor lung function and the serum IL-8 and IL-6 levels. A specific SUV39H1 inhibitor, chaetocin, induced a distinct COPD panel of inflammatory cytokines in normal PBMCs. Mechanistically, chaetocin reduced the SUV39H1 and H3K9me3 levels in the native IL-8 promoter in normal HSAEpCs, which mimicked unstimulated COPD HSAEpCs and led to decreased HP-1α levels and increased RNA polymerase II levels. SUV39H1 knockdown reproduced the pattern of COPD inflammation, whereas SUV39H1 overexpression in COPD HSAEpCs rescued the H3K9me3 levels and suppressed inflammation. In COPD mice, chaetocin further repressed the SUV39H1/H3K9me3 levels and enhanced inflammation. SUV39H1 epigenetically controls a distinct panel of pro-inflammatory cytokines. Its reduction in COPD leads to a loss of the repressive chromatin mark H3K9me3 and confers an abnormal inflammatory response to stimulators. SUV39H1 and its regulatory pathways are potential therapeutic targets for COPD.