Solvent-based Paints Research Articles

High-solution emission characters and health risks of volatile organic compounds for sprayers in automobile repair industries.

The increasing automobile repair industries (ARIs) with spray facilities have become an important volatile organic compound (VOC) pollution source in China. However, the VOC health risk assessment for long-term exposure in ARIs has not been well characterized. In this study, though sampled VOCs from 51 typical ARIs in Beijing, the relationship between emission patterns, average daily exposure concentrations (EC), and health risks was comprehensively analyzed with the health assessment method. Results showed that concentrations of 117 VOCs from the samples ranged from 68.53 to 19863.32 μg·m-3, while the ARI operator's daily VOC inhalation EC was 11.24-1460.70 μg·m-3. The organic VOC (OVOC) concentration accounted for 73.16 ~ 94.52% in the solvent-based paint workshops, while aromatics were the main VOC component in water-based paint spraying (WPS) workshops, accounting for 70.08%, respectively. And the method of inhalation exposure health risk assessment was firstly used to evaluate carcinogenicity and non-carcinogenicity risk for sprayers in ARIs. The cumulative lifetime carcinogenic risk (LCR) for 24 sampled VOCs were within acceptable ranges, while the mean hazard index (HI) for 1 year with 44 sampled VOCs was over 1. Among them, ethyl alcohol had a high carcinogenic risk in both mixed water-based paint (MP) and solvent-based paint workshops. The mean HI associated with aromatics were 2.88E - 3 and 4.30E - 3 for 1 h in MP and WPS workshops. O-ethyl toluene and acetone are VOC components that need to be paid attention to in future paint raw materials and spraying operations. Our study will provide the important references for the standard of VOC occupational exposure health limits in ARIs.

Enhancing Process Stability and Quality Management: A Comprehensive Analysis of Process Capability Indices

Process Capability Indices such as Process Capability Index (Cp) and Corrected Process Capability Index (Cpk), along with Process Performance Index (Pp) and Process Performance Corrected Index (Ppk), are most commonly used tools in quality management within manufacturing processes. They determine whether a process is capable of producing products within established tolerance limits, addressing both short-term and long-term variability. Despite widespread use, the analysis of Process Capability Indices often overlooks special variability within processes, which may lead to misleading interpretations of a process's capability, especially when the determination of tolerance limits is inadequately conducted. This article aims to verify the hypothesis that current analyses of Process Capability Indices fail to consider special variability, which could mislead the interpretation of a process's ability to meet its specifications. Statistical analyses were conducted using the Minitab software, based on dynamic viscosity measurements from the production process of solvent-based paint, to explore the implications of special variability on the interpretation of Process Capability Indices. The study revealed that while Process Capability Indices are useful for identifying quality management opportunities, their effectiveness is limited when special variability is present, often resulting in misinterpretations of a process's true capabilities. The findings highlight the need for methodologies that incorporate considerations of all forms of variability to ensure accurate process capability assessments. This gap in traditional analyses can affect the strategic decision-making in quality management, suggesting a critical area for further research and methodological development. The research confirms the need for a revised approach in analyzing Process Capability Indices, advocating for advanced methods that accurately reflect all forms of variability to improve quality management practices. Future research should focus on developing these methodologies to ensure more reliable and effective use of Process Capability Indices in quality management.

Combination of lean thinking and A3 problem-solving methods to reduce the cost of purchasing cleaning agents in a paint manufacturer in Indonesia

One of the manufacturing industries for making solvent-based and water-based paints is located in the Cikarang area, West Java. This paint company is experiencing an increase in production due to a large number of requests for various products. The company's level of cleanliness in maintaining quality and reducing waste of operational costs is the key to the company's success in becoming an international standard company. Every year the company incurs the cost of purchasing a cleaning agent imported from Norway because it is a basic requirement in material inventory to meet customer satisfaction. The purpose of this research is to reduce the wasted costs of purchasing cleaning agents originating from imports, maintaining 5S conditions, and fulfilling customer satisfaction. The method used in this study is a combination of the lean thinking method and the most effective A3 problem-solving method which can help create consistent, clear, and structured problem-solving documentation. This research found that there is a very large cost to buy a cleaning agent in 2021 of IDR 114,331,430 which must be spent by companies in using cleaning agents. The results of this study found that there was a reduction in the cost of purchasing a cleaning agent in 2022 to IDR 4,897,900. Therefore this paint company gets operational cost savings in purchasing cleaning agent materials of 97.71%.

Near-field exposures and human health impacts for organic chemicals in interior paints: A high-throughput screening

Interior paints contain organic chemicals that might be harmful to painters and building residents. This study aims to develop a high-throughput approach to screen near-field human exposures and health impacts related to organic chemicals in interior paints. We developed mass balance models for both water- and solvent-based paints, predicting emissions during wet and dry phases. We then screened exposures and risks, focusing on Sri Lanka where residential houses are frequently repainted. These models accurately predict paint drying time and indoor air concentrations of organic chemicals. Exposures of both painter and household resident were estimated for 65 organic chemicals in water-based and 26 in solvent-based paints, considering 12 solvents. Chemicals of concerns (CoCs) were identified, and maximum acceptable chemical contents (MACs) were calculated. Water-based paints generally pose lower health risks than solvent-based paints but might contain biocides of high concern. The total human health impact of one painting event on all household adults ranges from 1.5 × 10-3 to 2.1 × 10-2 DALYs for solvent-based paints, and from 4.1 × 10-4 to 9.5 × 10-3 DALYs for water-based paints. The present approach is a promising way to support the formulation of safer paint, and is integrated in the USEtox scientific consensus model for use in life cycle assessment, chemical substitution and risk screening.

Effect of Paint Exposure Among Paint Workers and DNA Damage: A Scoping Review

Paint contains various complex chemical mixtures, such as aliphatic hydrocarbons, aromatic hydrocarbons (primarily toluene), ketones, and benzene as reported at previous studies. Toxicity from some chemicals can cause early DNA damage with various factors. A scoping review was conducted via literature review on relevant studies on the effect of paint exposure on paint workers and DNA damage. A systematic search was conducted in October 2021 via PubMed, Scopus, and Web of Science databases. The key terms used were paint, solvent-based paint, organic solvent, mixed organic solvent, occupational exposure and DNA damage, oxidative stress, genotoxicity on a painter, paint worker. From 561 articles, only 13 articles were finally selected based on the inclusion, exclusion criteria, and eligibility criteria. The literature showed that biomonitoring studies on painters were consistently reporting positive and significant DNA damage due to exposure to different types of compounds mixed in a paint. However, there were fewer studies on paint manufacturing factory workers compared to painters while paint manufacturing workers exposed various chemical everyday during the paint production which potentially susceptible to occupational toxicity. In conclusion, this review suggests that exposure to paints could induce early DNA damage among paint workers and further investigations on paint exposure among paint manufacturing factory workers and the DNA damage were needed in order to improve occupational health among paint workers in the future.

Examining the Corrosion Behavior of The 6061-T6 Al Alloy Inside Seawater With Decorative Gold- And Silver-Color Coating

This study examined the corrosion resistance of the metallic paint-coated, uncoated, and damaged paint-coated form of the high-strength 6061 T6 Al alloy inside seawater. Solvent-based paint containing two different metallic pigments produced with an alkyd binder was produced and the coating of Al 6061 T6 alloy was made with this paint. To determine the course of corrosion electrochemical impedance spectroscopy method was used. Ecor and Rp values were calculated from potential and current change values. As a result, it was determined from the Ecor, Rp, SEM -EDX images, and Nyquist curves that the corrosion resistance of impact coatings was lower. The corrosion resistance of gold color paint substantially containing copper pigment was lower than that of silver color paint containing Al pigment was observed.

‘The brighter the worse’: Lead content of commercially available solvent-based paints intended for residential use in Pakistan

Background: Environmental pollution and exposure to lead (Pb) through household paint continue to be a great concern, especially for low- and middle-income countries (LMICs). Methods: We measured the Pb levels of solvent-based paints commercially available in Karachi, Pakistan. We visited major markets and collected commonly available brands of paint, sampling the yellow, red, and white colors of each. The paint samples’ Pb content was measured using inductively coupled argon plasma atomic emission spectrometry (ICP-AES). Results: Of the 60 analyzed paint samples, 24 (40%) contained Pb levels of >100 ppm (beyond the legal limit in Pakistan), with a maximum of 97,000 ppm (dry weight). Sixteen (76.2%) of the 21 yellow paints (range: 5,100–97,000 ppm, IQR: 36,900 ppm), seven (37.0%) of the 19 red paints (range: 220–1,800 ppm, IQR: 255 ppm), and one (5%) of the 20 white paints (870 ppm) contained Pb levels of >100 ppm. Of the 60 paints, 45 were produced by domestic Pakistani companies (51% exceeding the limit) and 15 by multinational companies (7% exceeding the limit). Conclusions: Although Pakistani regulations have restricted Pb content in paints to <100 ppm since 2017, these regulations are poorly implemented, as highlighted by this study. We therefore recommend that paint manufacturers comply with national standards and internationally recommended Pb limits to ensure the health and safety of children and other populations in Pakistan.

Sector-based volatile organic compound emission characteristics and reduction perspectives for coating materials manufacturing in China

Coating materials manufacturing, with heavy use of organic raw materials and excipients, has become an important industrial source of ambient volatile organic compounds (VOCs). Effective control measures must be developed which rely on a complete understanding of both the current emission characteristics and future emission projections. Thus, a comprehensive whole-process method was proposed and local investigations and measurements were conducted to acquire the material balance-based emission factors (EFs) and sector-based VOC emission characteristics in China. Then, its historical emission trends were evaluated and future reduction perspectives were also projected. The results indicate that: (1) the non-controlled VOC EFs for different coatings were 80 g/kg solvent-based paint, 11 g/kg water-based paint, 49 g/kg varnish, 9 g/kg others (pigment, dyestuff, auxiliary), and 70 g/kg ink, respectively. (2) The VOC emissions increased from 0.34 Gg in 1949 to 872.72 Gg in 2018, and solvent-based paint was always the largest contributor (69–83%). Guangdong attributed the highest emissions (24.1%) in 2018, followed by Jiangsu (10.7%) and Sichuan (10.5%) provinces. The most abundant species were aromatics. (3) Disposal facility efficiency and VOC collection rate together determined the total process treatment efficiency. The disposal efficiency of adapted facilities could reach 90–99%, but the unmaintained or unsuitable facilities are more general and greatly reduced in efficiency. The collection rate could be up to >90% but only averaged about 40%. (4) Improving the treatment efficiency and expanding the market for green paint are the main pathways to reducing VOC emissions, and three scenarios were hereby set with increasing intensities. Compared to the non-controlled scenario, if basic or stringent control measures were fully implemented in China in 2030, the VOC emissions would be reduced by 70% or 81%, respectively.

Pyrolytic kinetics, reaction mechanisms and gas emissions of waste automotive paint sludge via TG-FTIR and Py-GC/MS

The present study experimentally quantified the pyrolysis behaviors of waste solvent-based automotive paint sludge (OAPS) and water-based automotive paint sludge (WAPS) at four different heating rates using thermogravimetric-Fourier transform infrared (TG-FTIR) spectrometry and pyrolysis-gas chromatography-mass (Py-GC/MS) spectrometry analyses. Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods combined with the master-plots method were employed to investigate the pyrolysis kinetics and reaction mechanisms of waste automotive paint sludge. Three reaction stages and three reaction peaks in stage 2 were distinguished for both OAPS and WAPS degradation. The average activation energy (Ea) estimates for OAPS (FWO: 179.09 kJ/mol; KAS: 168.28 kJ/mol) were slightly higher than WAPS (FWO: 175.90 kJ/mol; KAS: 164.80 kJ/mol) according to FWO and KAS methods. The main pyrolysis reaction mechanisms of both OAPS and WAPS closely matched with the order-based model corresponding to 3rd and 2nd order random nucleation on an individual particle. The evolved gas species of CH4, CO2, phenols, NH3, H2O, and CO from OAPS and WAPS pyrolysis were identified by TG-FTIR. According to Py-GC/MS, hydrocarbons (47.2%) and O-components (42.7%) were relatively large after OAPS and WAPS pyrolysis, respectively. Melamine was the most abundant N-component product after pyrolysis of OAPS (5.8%) and WAPS (4.8%).

Emission characteristics, risk assessment and scale effective control of VOCs from automobile repair industry in Beijing

Automobile repair is regarded as a typical domestic source of VOCs in China characterized by numerous sites, wide dispersion and intermittent VOCs emissions. It is of great importance to study and control VOCs from such activities. In this research, emission characteristics, risk assessment and scale effective control of VOCs from automobile repair in Beijing were studied. Results showed that coating spraying and baking were the main processes of VOCs and the major species determined were mostly oxygen-containing VOCs and aromatic hydrocarbons in the case of solvent-based coating usage. Meanwhile, alkanes were determined and accounted for 40 % of total VOCs emissions during the water-based coating spraying and baking. Generally, the total determined VOCs during the automobile repair processes were 1.06–1.27 mg/m3 and 2.93–53.46 mg/m3 for the usage of water-based and solvent-based paint, respectively. Health risk assessments indicated that the residents in the region about 30 m high within a radius of 20 m around the automobile repair plants might suffer from both serious non-carcinogenic and carcinogenic risk threats in the case of solvent-based coating usage in that the values of total hazard index (HI) represented by dichloropropane and acrolein were higher than 1 and the value of lifetime cancer risk (LCR) represented by dichloroethane was higher than 10−5. Besides, those in the region about 30 m high and within a wider radius of 340 m might suffer from carcinogenic risk threat with a certain probability (LCR > 10−6) no matter either solvent-based or water-based coatings were used. As for the scale control of VOCs from automobile repair, independent adsorption by activated carbon combined with mobile regeneration by catalytic combustion was also proposed as an efficient way.

Characterizing the emission behaviors of cumulative VOCs from automotive solvent-based paint sludge.

Volatile organic compounds (VOCs) diffused from paint sludge are potential hazard contributing significantly to environmental pollution and exposure to them can cause severe health issues. In this paper, a diffusion-controlled model was firstly developed for characterizing the emission behaviors of cumulative VOCs from automotive solvent-based paint sludge based on the worst field management scenario. The presented model is characterized by two key parameters: the diffusion coefficient (Dm) and the initial emittable concentration (Cm,0), which can be simultaneously obtained by our proposed ER-history method. Four major components were detected including 1-butanol, butyl acetate and 1,2,4-trimethylbenzene and 1-ethyl-4-methylbenzene. In addition, the model was validated by using environmental data in a ventilated test chamber, proving that the model is reliable and convincing. However, relative deviations of 1-butanol and butyl acetate are larger than those of 1,2,4-trimethylbenzene and 1-ethyl-4-methylbenzene, indicating that the model is more accurate for predicting hydrophobic VOCs release than those of hydrophilic VOCs. Besides, an increase in Cm,0 and Dm tends to enhance VOCs cumulation release. Our studies provide new insight into experimental designs for rapid model parameters measurement and a sound basis for estimating VOCs cumulative release from paint sludge as well as for hazardous waste.

Lead levels of new solvent-based household paints in Zimbabwe and Botswana: A preliminary study.

BackgroundLead paint remains a major potential source of lead poisoning globally, but there has been no documentation on lead content in solvent paints available on the markets in Zimbabwe and Botswana.AimTo determine the lead content of solvent-based paints available on the market in Zimbabwe and Botswana and identify a need for a larger study to inform policy.MethodsThis pilot study was conducted in Harare, Zimbabwe, and Gaborone, Botswana. Popular brands of solvent-based household paints were bought from hardware shops in Harare (10 samples) and Gaborone (19 samples). Samples were analysed for lead content using inductively coupled plasma-atomic emission spectrometry.ResultsSeventy percent of samples from Zimbabwe were found to contain lead above 90 parts per million (ppm), the recommended regulatory limit, with ranges from less than 60 ppm to 12 000 ppm. Twenty percent of Zimbabwean samples had lead levels above 10 000 ppm. No samples from Botswana had lead concentration above the detection limit, with all levels below 100 ppm.Lesson LearntData strongly suggest very high lead content in popular brands of solvent paints in Zimbabwe, indicating a need for a larger, well-designed study for policy direction.

A comparison of complexation induced brittleness in PEI/PSS and PEI/NaPSS single-step coatings

In the field of coatings, there is a major trend towards the reduction of volatile organic compounds by developing water-based alternatives for traditional solvent-based paints. Complexes of oppositely charged polyelectrolytes have recently emerged as a promising candidate for such coatings. Recently, we developed an ammonia-evaporation induced complexation approach to form polyelectrolyte complex films of two weak polyelectrolytes in a single step. Here, we extend this method by applying it to a combination of PEI/PSS, a weak polycation and a strong polyanion. Homogenous solutions at different ratios were successfully prepared. After casting and drying, dense and optically transparent layers were formed. As a comparison, PEI/NaPSS was also studied. Contrary to PEI/PSS, the pH in PEI/NaPSS films remains high during drying and NH3 evaporation, so PEI does not acquire a positive charge, thereby preventing complexation. We show that this leads to large differences in the properties of the films, with the PEI/NaPSS films being more sensitive to water, more ductile, and more prone to phase separation. We also found that the mechanical properties of the films depend strongly on the charge ratio: films made at a PEI/PSS ratio between 2:1 and 1:1 formed the strongest complexes, resulting in films that swell relatively little in water, but that are also brittle and prone to cracking during drying. In this work, we report a systematic study into this promising system and show its potential and tunability.

A review on electrostatic powder coatings for the furniture industry

Although powder coatings have had a long history in metal-related industries, it is a relatively new technology for the furniture industry. However, its application on wood-based panels which are non-conductive and sensitive to high temperatures has rapidly increased with developments in low-temperature curing powder coatings and the production of special-grade MDF (medium density fibreboard) panels. Solvent based-paints are still the most used coatings in the furniture industry, followed by water based paints, and powder coatings. However, government legislation on the toxic chemicals used in solvents, particularly in relation to human health, has increased the consciousness of people which has forced furniture producers to use modern and environmentally friendly coating systems. There are many advantages of using powder coatings such as them being non-toxic, cost-effective, easy application, and durable to weathering. The powder coatings industry has recently developed low-temperature curing powders and process parameters for wood-based substrates, in particular for MDF. Regular MDF panels are not suitable for powder coating applications because the raw material characteristics, production processes, surface treatments, and storage conditions should be formulated according to powder-grade MDF requirements. MDF producers and furniture companies need to be informed about the details of the application process and key precautions. In this study, the powder coatings market, application processes, required characteristics of the MDF substrate, technological developments and recent studies are extensively given.

A pioneer of acrylic painting: new insights into Carmen Herrera\u2019s studio practice

Carmen Herrera, born on May 30th, 1915, is a Cuban American abstract minimalist artist, whose first solo show was held at the Whitney Museum of American Art, New York, in 2016–2017. On this occasion, a scientific study of five paintings from the artist’s time in Paris (1948–1953) revealed her pioneering use of solvent-based acrylic paints in post-war Europe. This article presents a second phase of research into Herrera’s work aiming to shed light on her studio practice and ascertain the possible presence of other early acrylic paints in her pre-1963 artistic production. A selection of four paintings, namely Iberia #25 (1948), Iberic (1949), Flights of Colors #16 (1949), and Early Dynasty (1953), was subjected to an analytical campaign that relied on both non-invasive and micro-invasive techniques. Results confirmed the use of both oil and solvent-based acrylic paints, supporting our primary research and uncovering the first-known occurrence of acrylic binders in Herrera’s Iberia #25. In all cases, the ground layer consists of a mixture of titanium white in its tetragonal form of rutile, anhydrite, and talc, while the color palette was found to be based on both traditional and modern pigments. In most areas, several paint layers appeared to be overlaid on top of one another, revealing a creative process that developed through subsequent compositions. Remnants of earlier paint layers, which appeared to have been scraped off before new ones were applied, were observed directly above the ground in some of the samples examined. In addition, Iberia #25 and Iberic, with analogous geometric and chromatic schemes, underwent technical imaging, which exposed pencil lines and notes underneath the paint layers likely indicative of the intended design and polychromy. Besides corroborating a major alteration in the current scholarship on the availability and use of acrylic-based artists’ paints in post-war Europe, this research provides new insights into Herrera’s materials, techniques, and studio practice. In addition, the results of this scientific study assisted the development of a suitable treatment plan for Iberic in preparation for its display in The Metropolitan Museum of Art’s galleries as part of the museum’s 150th anniversary exhibition Making The Met, 1870–2020.

Spatial distribution of health risks for residents located close to solvent-consuming industrial VOC emission sources

Emissions derived from the consumption of organic solvents have been proven to be the primary industrial source of volatile organic compounds (VOCs). In conjunction with epidemiologic studies, water-based paints (WBPs) and solvent-based paints (SBPs) were selected as representatives of newly developed solvents and traditional solvents, respectively, to simulate the effects of consuming solvents emitted during industrial production. And non-carcinogenic and carcinogenic risks to residents near emission sources were studied in detail. The results showed that the spatial distribution of health risks varied with meteorological conditions and type of emission source, and the prevailing wind direction strongly affected the distribution range and shape of the influenced area. The areas of influence maximized on heavy-polluting days for both WBP and SBP emission sources with the total span reaching 804 m and 16 km, respectively; meanwhile, the areas of influence for carcinogenic risk resulting from WBP emission sources were 1.2 and 2.3 times greater than those measured on fine and rainy days, respectively, and 1.8 and 2.9 times greater for SBP emission sources. Compared with WBPs, the total spans of negatively influenced regions resulting from SBP emission sources were 10.4, 12.5 and 19.9 times greater on fine, rainy and heavy-polluting days, respectively. Therefore, carcinogenic risk was the dominant health threat for populations residing close to solvent-consuming industrial emission sources. The findings suggest that newly developed solvents are capable of significantly reducing consequent health threats, nevertheless, they could still pose occasional threats to nearby residents under specific meteorological conditions.

Application of RCO Treatment on Automobile Coating Drying Waste Gas

With the increasingly serious environmental problems, China has adopted more and more strict industrial production emission policies. Haze pollutes the weather and limits the production of polluting enterprises have seriously affected the normal production process of the factory. The pollutants discharged in automobile manufacturing process are increasing, and the environmental pollution caused by automobile coating needs to be solved urgently. Because a large amount of solvent-based paint is used in the production process, the pollution caused by volatile organic compounds is difficult to avoid. RCO is a new technology in the field of automobile coating waste gas treatment. Application of RCO in automobile coating waste gas treatment is studied.

Surface coating and speckling of the human iliotibial tract does not affect its load-deformation properties

Stochastic surface patterns form an important requirement to facilitate digital image correlation and to subsequently quantify material properties of various tissues when loaded and deformed without artefacts arising from material slippage. Depending on the samples’ natural colour, a surface pattern is created by speckling with colour or dye only, or it requires combined surface coating and speckling before to enhance the contrast, to facilitate high-quality data recording for mechanical evaluation. However, it is unclear to date if the colours deployed for coating and speckling do significantly alter the biomechanical properties of soft tissues. The given study investigated the biomechanical properties of 168 human iliotibial tract samples as a model for collagen-rich soft tissues, separated into four groups: untreated, graphite speckling only, water-based coating plus graphite speckling and solvent-based coating plus graphite speckling following a standardized approach of application and data acquisition. The results reveal that elastic modulus, ultimate tensile strength and strain at maximum force of all groups were similar and statistically non-different (p ≥ 0.69). Qualitatively, the speckle patterns revealed increasing contrast differences in the following order: untreated, graphite speckling only, water-based coating plus graphite speckling and solvent-based coating plus graphite speckling. Conclusively, both coating by water- and solvent-based paints, as well as exclusive graphite speckling, did not significantly influence the load-deformation parameters of the here used human iliotibial tract as a model for collagen-rich soft tissues. In consequence, water- and solvent-based coating paints seem equally suitable to coat collagen-rich soft tissues for digital image correlation, resulting in suitable speckle patterns and unbiased data acquisition.

Influence of the environmental relative humidity on the inflammatory response of skin model after exposure to various environmental pollutants

The skin is an essential barrier, protecting the body against the environment and its numerous pollutants. Several environmental pollutants are known to affect the skin, inducing premature aging through mechanisms including oxidative stress, inflammation, and impairment of skin functions. Even climate conditions can impact the skin. Therefore, using a Reconstructed Human Epidermis (RHE), we tested the effect of two samples of fine particulate matters (PM0.3-2.5 – one metals-rich sample and the other organic compounds-rich), two Volatile Organic Compounds mixtures (VOCs – from a solvent-based paint and a water-based paint) and Tobacco Smoke (TS). All pollutants affected cellular functionality, but to a lesser extent for the water-based paint VOC. This effect was enhanced when RHE were preconditioned for 2 h by a semi-dry airflow (45% relative humidity) before pollutants application, compared to preconditioning by a humid airflow (90% relative humidity). In the absence of preconditioning, IL-1α, IL-6, IL-8, and RANTES were almost systematically induced by pollutants. When RHE were preconditioned by a semi-dry or humid airflow before being subjected to pollutants, the increase of IL-1α, IL-8, and RANTES falls into two groups. Similarly to RHE not treated with pollutants, RHE treated with VOCs after preconditioning by a semi-dry airflow showed increased IL-1α, IL-8, and RANTES release. On the contrary, RHE treated with PM or TS after preconditioning by a semi-dry airflow show a lower increase in IL-1α, IL-8, and RANTES compared to preconditioning by a humid airflow. The effect of real environmental relative humidity conditions of the air, combined with acute exposure to various environmental pollutants, seemed to relate mainly to structural changes of the skin, determining the outcome of the inflammatory response depending on the physicochemical characteristics of pollutants.

Characterization of Water-Based Paint and Coating Film with Cellulose Nanofiber

Transition from solvent-based paints to water-based paints in the painting industry has progressed to reduce the use of volatile organic compounds, which are harmful to humans and the environment. However, water-based paints have a problem with paint workability because of sagging. Cellulose nanofiber (CNF), which has attracted attention as a novel naturally available material, exhibits high mechanical strength, thickening effects, and a low coefficient of thermal expansion. To resolve difficulties related to water-based paints, we examined paint and coating films characteristics after adding CNF. Results demonstrated that adding 0.2 mass% CNF can prevent sagging. Paint separation attributable to pigment sedimentation was prevented for 10 days. By adding 0.5 mass% CNF, the tensile strength of a coating film became more than double that of a non-CNF coating film. Testing using ballotini method indicated that CNF addition decreased the coating film surface dryness. Measurements using AC impedance indicated decreased coating film water resistance.