Air Dry Research Articles

Effect of Drying Methods on the Phenolic Compounds and Antioxidant Activity of Leaf of Agarwood (Aquilaria malaccensis Lam.)

This study is a preliminary analysis of the effect of various drying techniques on the phenolic components and antioxidant capability for developing protocols to produce herbal products from Aquilaria malaccensis. Aquilaria leaf samples (ALS) were subjected to different drying methods such as air-dry (AD), oven-dry (OD), sun-dry (SD), drying with food dehydrator (DD), and a combination of air-dry and use of dehydrator (CAD). After drying and grinding, samples were infused with hot water. Different parameters such as water extract, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activities were evaluated. Results revealed that there was no significant difference in the water extract of ALS among different methods. High TPC concentrations were recorded at SD, OD, and DD. The highest TFC concentration was observed in CAD and was significantly different among the drying treatments. Further, using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, the dehydrated-ALS possessed the highest antioxidant capacity of 524.33 ± 0.04 μmol TEAC/g among the treated samples. Meanwhile, based on the cupric reducing antioxidant capacity (CUPRAC) assay, the highest antioxidant activity among the treatments was sundried-ALS with a value of 391.70 ± 0.037 μmol TEAC/g sample. Based on these findings, the drying methods – particularly utilizing a dehydrator, sun- drying, or a combination of air-drying and using a dehydrator – all preserve the phenolics and antioxidant properties of A. malaccensis. Overall, the drying process significantly influenced the chemical characteristics and antioxidant activity of A. malaccensis tea.

Post-fire behavior of geopolymer concrete with sodium silicate waste as an alternative to conventional river sand

Purpose The present work focuses on evaluating the physical and mechanical characteristics of geopolymer concrete (GPC) by replacing the sodium silicate waste (SSW) in place of traditional river sand. The aim is to create eco-friendly concrete that mitigates the depletion of conventional river sand and conserves natural resources. Additionally, the study seeks to explore how the moisture content of filler materials affects the performance of GPC.Design/methodology/approach SSW obtained from the sodium silicate industry was used as filler material in the production of GPC, which was cured at ambient temperature. Instead of the typical conventional river sand, SSW was substituted at 25 and 50% of its weight. Three distinct moisture conditions were applied to both river sand and SSW. These conditions were classified as oven dry (OD), air dry (AD) and saturated surface dry (SSD).Findings As the proportion of SSW increased, there was a decrease in the slump of the GPC. The setting time was significantly affected by the higher percentage of SSW. The presence of angular-shaped SSW particles notably improved the compressive strength of GPC when replacing a portion of the river sand with SSW. When exposed to elevated temperatures, the performance of the GPC with SSW exhibited similar behavior to that of the mix containing conventional river sand, but it demonstrated a lower residual strength following exposure to elevated temperatures.Originality/value Exploring the possible utilization of SSW as a substitute for river sand in GPC, and its effects on the performance of the proposed mix. Analyzing, how varying moisture conditions affect the performance of GPC containing SSW. Evaluating the response of the GPC with SSW exposed to elevated temperatures in contrast to conventional river sand.

Research and Application of Intelligent Water Source Well Air Defense Pumping and Dry Burning Technology

The surface water injection technology for developing low permeability reservoirs comes from the water supply of water source wells. The groundwater resources in oil fields are limited, with high water consumption and a decrease in water level, lacking effective monitoring methods. In recent years, there have been frequent occurrences of unsafe waste of electrical energy due to dry burning during pumping in water source wells, which has seriously affected the normal water injection of oilfield formations. In order to prevent dry burning of water source wells by pumping air, research on intelligent air defense dry burning technology for water source wells has been carried out. The automatic pump stop alarm at low water level and the automatic pump start at high water level avoid the phenomenon of dry burning during pumping in the water source well, ensure the normal operation of the water source well, and ensure sufficient water injection from the source. Reduce employee labor intensity and achieve the goal of optimizing human resources. Associate the start and stop status of the water source well with the tank position of the water injection station to achieve automatic water distribution and inventory, achieve digital management and fine management, and achieve the goal of reducing costs and increasing efficiency, which has promotion value.

Effect of moisture content of recycled aggregates on workability, compressive strength and durability of concrete-A review

It is necessary to clarify the influence of different moisture contents of recycled aggregates (RA), including oven dry (OD), saturated surface dry (SSD), air dry (AD), etc., on the performance of recycled aggregate concrete (RAC) considering the time-dependent water absorption characteristic of RAs. By analyzing the previous literature, the effects of different moisture contents of RAs on the workability, compressive strength, and durability of RAC were discussed in detail. In addition, the microscopic mechanism was revealed based on the microstructure analysis. A lot of studies have shown that RAC prepared with RA in OD state had the largest fluidity when the same additional water was used. The slump loss of RAC decreases with the increase of water content of RAs, and when the moisture content of RA is higher than 50% of the water absorption of SSD, the slump loss is related to the additional method. The compressive strength and durability of RAC prepared with RAs in AD state were better than that prepared with RA in OD or SSD state. The shrinkage of RAC prepared with RA in OD state was greater than that prepared with RA in the SSD or AD state.

Quantitative interpretation of coal industrial components using a gray system and geophysical logging data: A case study from the Qinshui Basin, China

The content of industrial components of coalbeds, one of the main parameters of coalbed methane (CBM) reservoirs, is crucial in the entire coal mine resource exploration and exploitation process. Currently, using geophysical logging data to determine the content of industrial components is the most widely implemented method. In this study, the PZ block in the Qinshui Basin was employed as a target block to evaluate ash (Aad), fixed carbon (FCad), volatile matter (Vdaf), and moisture (Mad) under the air-dry (AD) base condition based on the autocorrelation between the geophysical logging curves and industrial component contents combined with the OBGM (1, N) model. The results indicate that 1) the geophysical logging curves combined with the OBGM (1, N) model can accurately predict the Aad and FCad contents and an increase in geophysical logging curve types can effectively improve the model performance, compared to using a single geophysical logging curve for prediction. 2) When predicting the Vdaf content, using the geophysical logging curves combined with Aad and FCad contents had the highest prediction accuracy. Further, prediction bias does not exist, compared to using only the geophysical logging curve or the autocorrelation between the industrial component contents. The entire evaluation process begins with an assessment of the Aad and FCad contents. Then, the Vdaf content was assessed using the content of these two industrial components combined with geophysical logging data. Finally, the Mad content was calculated using the volumetric model. Accurate application results were obtained for the verification of new wells, demonstrating the efficacy of the method and procedure described in this study. 3) The OBGM (1, N) model has the highest prediction accuracy compared with the multiple regression and GM (0, N) models, which have the same computational cost. The geophysical logging interpretation model of the proposed coalbed industrial component contents is simple to calculate and suitable for small samples, providing a new method for the evaluation process of industrial component contents.

Stress-Strain-Sorption Behaviour of Smectites Upon Exposure to Dry and Wet CO2

The swelling-shrinkage behavior of smectites induced by interlayer uptake or sorption of CO2 and H2O has been investigated with increasing interest recent years, primarily because of its potential impact on the sealing efficiency of clay-bearing caprocks overlying CO2 storage reservoirs. To get a better understanding of the stress-strain-sorption coupling in smectite exposed to supercritical CO2, we performed multiple stepwise axial loading and unloading, oedometer-type experiments on ∼1 mm thick discs of pre-pressed Na-SWy-1 and of Ca-SAz-1 montmorillonite. Initially air-dry (AD) samples were first tested in the presence of wet CO2 (20% RH) at 10 MPa pressure, and in the vacuum-dry (VD) state in the presence of pure (dry) CO2 at 10 MPa. The samples were incrementally loaded and unloaded at 40°C, employing effective axial stresses ranging from 0.5 to 44 MPa. Control tests using wet and dry He or Ar instead of CO2, were performed to distinguish strains due to loading-related CO2 sorption/desorption from purely poroelastic effects. All samples saturated with CO2 exhibited 30–65% lower apparent stiffness moduli than when saturated with He or Ar, showing that CO2 adsorption/desorption altered the mechanical response of pre-pressed smectites. Relative to the He and Ar tests, swelling strains of a few % (corrected for poroelastic effects) were measured for AD Na-SWy-1 smectite exposed to wet CO2, decreasing from 4.9 to 3.8% with increasing effective axial stresses in the range 1.6–36.2 MPa. AD SAz-1 material exhibited similar tends. VD samples tested with dry CO2 showed much smaller relative swelling strains (0.5–1.5%), which also decreased with increasing applied effective stresses. The experimental data on relative swelling strain versus effective stress are well fitted by a recent thermodynamic model for stress-strain-sorption behavior in coal. Results derived from model fits indicate that smectite-rich rocks have significant storage capacity for CO2 at shallow depths (up to 1.5–2 km) through CO2 sorption by the clay minerals. However, this component of storage capacity is reduced by more than 80% with increasing burial depth beyond 3 km. The model provides a first step towards modelling stress-strain-sorption effects in smectite rich caprocks penetrated by CO2, though further refinements are needed for broader application to the smectite-CO2-H2O system.

Air Dry Technique for the Preparation of Meiotic Chromosomes from the Testes of Silkworm Bombyx mori L.

One strain of mulberry silkworm Bombyx mori L., namely NB4D2 at the age of the fifth instar, was selected as an experimental insect. During the fifth instar, testes were used to prepare meiotic chromosomes. The air dry technique for preparing meiotic chromosomes was developed and standardised. Both temporary and permanent micro slides showed clear different stages of meiosis. The different meiotic stages were observed under 1000x magnification and photographed using conventional photographic techniques.

Impact of various dentinal drying methods on the adhesion of glass ionomer restorations to primary teeth

Background: Air drying is considered the most simple and effective method to achieve solvent evaporation. The present study was conducted to assess Impact of various dentinal drying methods on the adhesion of glass ionomer restorations to primary teeth. Materials & Methods: 90 primary teeth of both genders were grounded to a flat dentinal surface. Specimens were randomly divided into three groups. Group I were subjected to air dry, group II to blot dry, and group III to suction dry. Each group comprised of 30 teeth. 10 specimens from each group were dried for 2 seconds, 5 seconds, and 10 seconds. Results: Group I teeth were subjected to air dry, group II to blot dry, and group III to suction dry. Each group comprised of 30 teeth. The mean shear bond strength at 2 seconds, 5 seconds, and 10 seconds in group I was 3.2, 5.4 and 5.3 respectively. The mean bond strength was 2.6. 3.5 and 4.6 in group II and 3.1, 4.2 and 4.0 in group III respectively. The difference was significant (P< 0.05). Conclusion: The maximum shear bond strength of the glass ionomer restoration was observed in the air?dry group.

Pre- and post-fire mechanical performances of high calcium fly ash geopolymer concrete containing granite waste

The purpose of this study was to investigate the properties of fresh and hardened geopolymer concrete made with granite fines waste. In order to reduce the consumption of natural aggregates, the granite waste sourced from the stone industry was used as fine aggregates for making geopolymer concrete cured at room temperature. Natural river sand was replaced with the granite waste at 25% and 50% by weight. The effect of moisture conditions of fine aggregates on the properties of the geopolymer concrete were also investigated. The fine aggregates were prepared in three different moisture states: saturated surface dry (SSD), air-dry (AD) and oven-dry (OD). It was found that the slump flow of the geopolymer concrete increased with the increasing proportion of the granite waste in the mixture. Meanwhile, the initial and the final setting times were not influenced by the inclusion of the granite waste except when the fine aggregates were saturated. The presence of angular shaped particles enhanced the early compressive strength of geopolymer concrete with 50% replacement of natural sand by the granite waste. Furthermore, the fire test results showed that the geopolymer concrete with the granite waste had a similar spalling behavior to the one made entirely with the natural sand, but tended to show inferior post-fire residual strengths, particularly when the oven-dried aggregates were used.

Structural Analysis of Interstratified Illite-Smectite by the Rietveld Method

Rietveld method is a powerful tool in obtaining structural information of clay minerals by using of X-ray diffraction (XRD) patterns. However, the interstratified illite-smectites (I-S) show various stacking defects preventing the direct application of this method. It was shown that the Rietveld method combined with a recursive structure-factor calculation can be used for describing the stacking disorder of I-S. In this study, a series of samples with different stacking sequences and different proportions of layer types were chosen to verify the applicability of Rietveld method in determination of structural parameters of I-S. The Rietveld refinements were carried out on powder samples and oriented specimens in air-dry (AD) and ethylene glycol (EG) state. The structural information obtained by X-ray fluorescence (XRF) and thermal analysis were used as an independent test of the reliability of the refinements. The refined and experimental results were compared systematically and the relationship between structural parameter was discussed. For powder and oriented specimens, the refined results of occupancies of potassium and iron and the proportion of illitic layers showed consistent results. The refined value of cis-vacant layers was in good agreement with the experimental data. The reliability of the refinements increased with increasing proportion of illitic layers.

Wear behavior of extruded ZK60 magnesium alloy in simulated body fluid with different pH values

Two specimens were prepared along the extrusion (ED) and transverse (TD) directions of the extruded ZK60 magnesium alloy bar, respectively. The wear behavior of ED and TD specimens in air (Dry) and simulated body fluid (SBF) of different pH values (pH 4, 7.4 and 9) was evaluated using ball-on-disk configuration. The wear morphology of specimens was characterized by three-dimensional white light interference profiler, scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). The results indicated that pH value had a significant effect on the wear behavior of specimens. The average friction coefficient of ED and TD specimens in each environment decreased in the following order: pH 7.4 ≈ pH 9 > Dry > pH 4, and the wear volume decreased in the following order: Dry > pH 4 > pH 7.4 ≈ pH 9. Abrasive wear and oxidative wear were the main wear mechanisms of ED and TD specimens in air, and corrosive wear was taken place in SBF of pH 4, 7.4 and 9. The formation of Mg(OH)2 film improved the wear resistance of specimen in SBF. The wear behavior of ED and TD specimens in SBF of pH 4 showed an orientation correlation, and the wear volume of TD specimen was greater than that of ED specimen. The effect of pH value and initial texture on the wear behavior of magnesium alloy was discussed.

Spatiotemporal shading regulates anthocyanin, proanthocyanidin, and sucrose accumulation in black soybean seeds

AbstractThe accumulation of soybean seed constituents such as anthocyanin, proanthocyanidin (PA), and sucrose is affected by various environmental stresses. Considerable information is available on the effects of different environmental stresses; however, the effect of shade at various development stages on the accumulation of the various seed constituents remains elusive. We investigated the effect of shade application on anthocyanin, PA, and sucrose contents at different seed development stages of two black soybean [Glycine max (L.) Merr.] varieties. This study comprised two separate trials: maize–soybean relay intercropping (IC) and soybean monoculture. The shade treatments in the soybean monoculture trial comprised shade applications at whole growth stage, at vegetative stage (SV), and at reproductive stage (SR) and a no‐shade control. Anthocyanin, PA, and sucrose contents were analyzed from seeds obtained at development stages of full‐size seed (R6), physiological maturity (R7), full maturity, 95% mature pods on the plant (R8), and natural air dry (AD). Genotype, shade, and planting season and their interactions had a strong influence on anthocyanin, PA, and sucrose accumulation in soybean seeds at the different seed development stages. Among all the shade treatments, relay IC recorded the highest anthocyanin contents in 2017 (1.88 mg g−1) and 2018 (1.76 mg g−1) in AD seeds. In addition, the application of shade increased PA, and maximum PA (27.14 mg g−1) was obtained in the SV treatment at R6 stage. The overall best sucrose contents (6.14 mg g−1 in 2017 and 7.04 mg g−1 in 2018) were obtained in soybean seeds harvested at R8 under SV treatment.

Leaf harvesting severity affects total phenolic and tannin content of fresh and dry leaves of Moringa oleifera Lam. trees growing in Gauteng, South Africa

The most important chemicals common in Moringa oleifera Lam. leaves are polyphenols and tannins. They are synthesised during development and the amount and composition are primarily dependent on environmental conditions and factors such as leaf harvesting. Trials were conducted in the Gauteng Province at the University of Pretoria Experimental Farm on Hillcrest Campus (250 45′ 08.6″S, 280 15′ 30.S" E), with an altitude of 1372 m above sea level and an average annual rainfall of 640 mm. Five year old M. oleifera tree orchard were used for this study and treatments were laid in a randomised complete block design, where 12 plants were used in each plot within a row, with a plant spacing of 2 × 2 m2. Partial harvesting was done at 25% leaf removal, while severe leaf harvesting was done at 75% leaf removal. The control trees were not harvested, but only leaf (mature and immature) samples were harvested for analyses. Leaf samples from all plots were harvested in September, November, February and May in years 1 and 2. Leaf samples (equal quantities of immature and mature leaves) from partially, severely harvested and control plots were harvested and separated into batches, one to be analysed as fresh material and the other as dry material. The dry material was placed in paper bags and allowed to immediately air dry under normal room conditions of 26 °C. Partially harvested M. oleifera leaves produced an increased accumulation of total phenolic content (TPC) 35–44 g/kg dry weight, from spring to summer season, in comparison to severe harvesting 26–35 g/kg dry weight. With severe leaf harvesting (75%), because of probable lower photosynthetic capacity, phenols across September to May of years 1 and 2 decreased. The onset of low temperatures in May resulted mostly higher TPC and tannin build up, which means that cold stress may improve more bio-active compounds in the leaves. Dark and fully developed mature leaves mainly contained the highest amount of TPC. Moringa oleifera leaves collected and dried at each harvesting interval, instead of freshly milled, do show the same quantity of TPC and tannins across the season illustrating that air drying can be used as a post-harvest handling technique, extending shelf life without losses of vital phenols. With harvesting severity as a concern in Moringa, this study confirms that the TPC and tannins in mature and immature leaves did not rise to toxic levels for human consumption.

Development of an air drying index for lumber

Lumber is often air dried in an air drying yard prior to being placed in a dry kiln for final moisture content removal. The rate of the air drying process is dependent on local weather conditions and wood moisture content. Introduced more than 30 years ago, the Drying Index is a method to estimate the relative drying time using the difference in vapor pressures between the dry bulb and wet bulb temperatures. This paper extends its application and describes the development and use of an Air Drying Index to estimate the relative potential of a geographic location to air dry lumber based on the average monthly climate conditions for that location. The monthly Air Drying Index for 252 US locations is presented, and the annual mean for each location was used to develop an air drying map.

Energy and Exergy Analysis of Shower Cooling Tower with Variation in Inlet Air Dry Bulb Temperature for Industrial Application

Energy and Exergy Analysis of Shower Cooling Tower with Variation in Inlet Air Dry Bulb Temperature for Industrial Application

Nitrous oxide fluxes and nitrifier and denitrifier communites as affected by dry-wet cycles in long term fertilized paddy soils

Drying and rewetting events of soil represents a common physiological stress for soil microbial communities. We investigated the effect of alternate drying-rewetting cycles on N2O emissions and soil microbial communities in jar experiments with soil samples. The results showed that instant flooding and air-drying moments are two important steps of soil drying and rewetting periods influencing soil microbial communities and N2O emissions. N2O fluxes in the air dry (AD) steps were always higher than those in the instant flooding (IF) steps, especially in the early stages of AD and IF. The soil treated with long-term organic matter and chemical fertilizer promoted N2O emissions but inhibited the N2O release from newly applied urea when soil went through drying and rewetting events. Soil moisture content(s) also significantly affected the growth of ammonia oxidiser and denitrifier communities, with the functional gene abundance increasing with increasing soil moisture content. While comparing first and second cycles, N2O fluxes were six times higher in the first cycle than in the second cycle. It is concluded that sudden changes in moisture condition influenced the N2O flux, and nitrifier and denitrifier functional genes by affecting the growth of ammonia oxidiser and denitrifier communities.

Effect of Blood Contamination and Decontamination Procedures on the Microtensile Bond Strength of a New Self-etch Adhesive: An in vitro Study

ABSTRACT Aim The aim of the study was to evaluate the effect of blood contamination and decontamination procedures on the microtensile bond strength of a new self-etch adhesive before and after curing. Materials and methods A total of 90 human extracted mandibular molars were stored in 0.5% thymol solution and distilled water. Midcoronal sections were obtained using a diamond disk and the dentin surface was ground with 320 grit SIC abrasive paper. Universal self-etch adhesive (3M ESPC) and Filtex Z-250 resin composite were used. The dentin specimens were randomly divided into nine groups: Control group, group I—blood contamination before curing, group II—blood contamination before curing followed by air drying, group III—blood contamination before curing followed by rinsing with water and air drying, group IV—blood contamination before curing followed by rinsing with water, air dry, and reapplication of bonding agent, group V—blood contamination after curing, group VI—blood contamination after curing followed by air dry, group VII—blood contamination after curing followed by rinsing with water and air drying, group VIII—blood contamination after curing followed by rinsing with water, air dry, and reapplication of bonding agent. The microtensile bond strength was measured by universal testing machine and the data were analyzed by one-way analysis of variance (ANOVA) followed by Tukey's post hoc test. Results The contamination groups (I, V) showed the least bond strength followed by the decontamination groups (II, III, VI, VII). The reapplication groups (IV, VIII) restored the bond strength equal to control group. Clinical significance A contamination-free area is required for adequate adhesion. It is important to rule out measures to prevent and manage contamination, so as to achieve durable seal between composite resin and tooth surface. How to cite this article Shaikh A, Hegde V, Shanmugasundaram S. Effect of Blood Contamination and Decontamination Procedures on the Microtensile Bond Strength of a New Self-etch Adhesive: An in vitro Study. Int J Experiment Dent Sci 2017;6(2):80-83.

The effect of aggregate condition during mixing on the mechanical properties of oil palm shell (OPS) concrete

One of the key characteristics affecting the properties of OPS concrete is the saturation condition of the coarse aggregates used during mixing. In this current study, the effect of different aggregate saturation conditions during mixing on the slump, compressive, flexural and splitting tensile strength of OPS concrete was investigated. Three aggregate saturation conditions were employed, namely saturated-surface-dry (SSD), air-dry (AD) and sun-dry (SD). The results revealed that the SD mix had a higher slump value than AD mix and SSD mix. On the other hand, SSD mix registered better compressive, flexural and splitting tensile strength compared to the AD and SD mix. This suggests that the use of SSD aggregates is more effective in producing higher strength concretes which could be credited to the internal curing provided by the SSD aggregates.

Evaluating Soil Moisture Status Using an e-Nose.

The possibility of distinguishing different soil moisture levels by electronic nose (e-nose) was studied. Ten arable soils of various types were investigated. The measurements were performed for air-dry (AD) soils stored for one year, then moistened to field water capacity and finally dried within a period of 180 days. The volatile fingerprints changed during the course of drying. At the end of the drying cycle, the fingerprints were similar to those of the initial AD soils. Principal component analysis (PCA) and artificial neural network (ANN) analysis showed that e-nose results can be used to distinguish soil moisture. It was also shown that different soils can give different e-nose signals at the same moistures.

Potential Importance of Ozone in the Association Between Outdoor Air Pollution and Dry Eye Disease in South Korea.

Air pollution is an important public health concern and the ocular surface is continuously exposed to pollutants in outdoor air. Ocular surface abnormalities related to air pollution are thought to be a subtype of dry eye disease (DED). However, to date, there is no large-scale study evaluating an association between air pollution and DED that includes multiple air pollutants. To investigate associations between outdoor air pollution and DED in a Korean population. A population-based cross-sectional study using data on 16 824 participants in the fifth Korea National Health and Nutrition Examination Survey was conducted from January 1, 2010, to December 31, 2012. Data analysis was conducted from September 1 to 30, 2015. Dry eye disease was defined as previously diagnosed by an ophthalmologist or the presence of frequent ocular pain and discomfort. Outdoor air pollution measurements (mean annual humidity, particulate matter with aerodynamic diameter <10 µm [PM10], ozone, and nitrogen dioxide levels) were collected from 283 national monitoring stations in South Korea. Associations of multiple air pollutants with DED were assessed from multivariable logistic regression analyses. Sociodemographic factors and previously known factors associated with DED were applied as covariates (model 1 controlled for sociodemographic factors and model 2 controlled for sociodemographic, behavioral, and clinical factors). Among 16 824 participants (7104 men and 9720 women), higher ozone levels and lower humidity levels were significantly associated with symptoms and diagnosis of DED. In model 1, an increase in ozone levels of 0.003 ppm was significantly associated with symptoms and diagnosis of DED (symptoms: odds ratio [OR], 1.16; 95% CI, 1.02-1.30; P = .04; diagnosis: OR, 1.21; 95% CI, 1.05-1.40; P = .008), while a 5% increase in humidity levels was significantly associated with decreased symptoms and diagnoses of DED (symptoms: OR, 0.87; 95% CI, 0.77-0.98; P = .03; diagnosis: OR, 0.86; 95% CI, 0.76-0.97; P = .01). In model 2, an increase in ozone levels of 0.003 ppm was significantly associated with symptoms and diagnosis of DED (symptoms: OR, 1.17; 95% CI, 1.02-1.34; P = .03; diagnosis: OR, 1.27; 95 CI, 1.09-1.48; P = .002), while a 5% increase in humidity levels was significantly associated with decreased symptoms and diagnoses of DED (symptoms: OR, 0.88; 95% CI, 0.78-0.98; P = .045; diagnosis: OR, 0.86; 95% CI, 0.76-0.97; P = .02). In model 2, an increase in nitrogen dioxide of 0.003 ppm (OR, 1.12; 95% CI, 1.02-1.23 P = .02) was also associated with diagnosis of DED. Levels of sulfur dioxide and PM10 were not associated with symptoms or diagnosis of DED in model 1 or model 2 (P > .05 for each). Higher ozone levels and lower humidity levels were associated with DED in the Korean population, while PM10 level was not associated with DED.