PM2.5 exposure to marijuana smoke on golf courses and other public outdoor locations: A pilot observational study.

Secondhand exposure to cannabis smoke occurs in public outdoor locations due to outdoor smoking or leakage of indoor smoking. Very little is known regarding the actual levels of exposure. This study examined PM2.5 exposure to marijuana smoke, focusing on one type of public outdoor location - golf courses where illegal marijuana consumption is increasingly common. Based on 24 visits to 10 courses over a 6-month period, >20 % visits encountered marijuana smoke, with peak PM2.5 exposures up to 149 µg/m3. The levels of exposure depended upon the source type (smoking versus vaping) and the proximity to the smoker/vaper. Ten additional investigations were performed to measure marijuana secondhand exposure in other public outdoor locations (near a smoker in a public park, near a parked car with in-car smoking/vaping, and near a residential garage with indoor smoking/vaping). 23 encounters of marijuana exposure events were documented in total. Average outdoor exposures to PM2.5 close to public outdoor smoking and vaping (on golf courses and a public park) were >3 times as high as those near a car or a building with indoor marijuana emissions. The average outdoor exposure caused by the leakage of in-car secondhand smoke was higher than that caused by in-building emissions.

Measuring PM2.5 concentrations from secondhand tobacco vs. marijuana smoke in 9 rooms of a detached 2-story house.

The widespread legalization of recreational marijuana raises growing concerns about exposure to secondhand marijuana smoke. An important location for marijuana smoking is the home, but few measurements of air pollutant concentrations in the home are available for a marijuana joint fully smoked in one of its rooms. We used research grade calibrated real-time continuous PM2.5 air monitors in controlled 5-hour experiments to measure fine particle concentrations in the 9 rooms of a detached, two-story, 4-bedroom home with either a tobacco cigarette or a marijuana joint fully smoked in the home's living room. The master bedroom's door was closed, and the other bedroom doors were open, as was the custom of occupants of this residence. In two experiments with a Marlboro tobacco cigarette smoked by a machine in the living room, the 5-hour mean PM2.5 concentrations in 9 rooms of the home were 15.2 µg/m3 (SD 5.6 µg/m3) and 15.0 µg/m3 (SD 3.7 µg/m3). In contrast, three experiments with pre-rolled marijuana joints smoked in the same manner in the living room produced 5-hour mean PM2.5 concentrations of 38.9 µg/m3 (SD 10.6 µg/m3), 79.8 µg/m3 (SD 25.7 µg/m3) and 80.7 µg/m3 (SD 28.8 µg/m3). In summary, the average secondhand PM2.5 concentrations from smoking a marijuana joint in the home were found to be 4.4 times as great as the secondhand PM2.5 concentrations from smoking a tobacco cigarette. Opening 3 windows by 12.7 cm reduced the high PM2.5 concentrations from marijuana smoking by 67 %, but the PM2.5 levels still exceeded those produced by tobacco smoking with the windows closed.

PM2.5 exposure close to marijuana smoking and vaping: A case study in residential indoor and outdoor settings.

We conducted 35 experiments for spatial measurement of marijuana aerosols in a current smoker's residential spaces. Fine particulate matter (PM2.5) concentrations were measured every second at 1, 2, and 3 m horizontal distances from the smoker who performed prescribed 5-min smoking and vaping activities. In each experiment, five SidePak monitors measured PM2.5 concentrations at five different angles facing the front of the smoker, representing the worst-case exposures. We studied the effect of distance from the smoker for two marijuana sources - smoking a marijuana cigarette, or joint, and vaping a liquid-cartridge vaping pen. Experiments were conducted in the family room indoors and in the backyard outdoors where the smoker normally consumes marijuana. Indoor marijuana vaping had higher average exposures (5-min PM2.5) at 1 m distance than indoor marijuana smoking, but the levels from indoor vaping decreased more rapidly with distance (e.g., 77% reduction for vaping versus 33% for smoking from 1 to 2 m). Smoking and vaping in the outdoor environment reduce the average exposures down to <5% of the indoor levels at each distance. Cumulative frequency distributions of the 1-s PM2.5 concentrations revealed the frequencies of exceeding any selected transient peak exposure limit at a given distance. The frequency of exceedance decreased more quickly with distance for vaping than for smoking. Smoking and vaping outdoors made the transient peak exposures close to the source much less frequent than smoking and vaping indoors (e.g., <1% exceeded 1000 µg/m3 outdoors versus >20% indoors at 1 m). Plotting the frequency of exceedance versus distance could offer additional guidance for a recommended minimum distance from a marijuana source.

Elevated plasma YKL-40 level is found in the dogs with cancer and is related to poor prognosis.

YKL-40, a secreted glycoprotein, may serve as an autoantigen, which mediates multiple inflammatory diseases and cancers. A high YKL-40 serum level is correlated with metastasis and poor survival in a variety of human cancers. However, the role of YKL-40 in dogs is still under evaluation. Herein, we examined the associations between plasma YKL-40 level and YKL-40 autoantibody (YAA) titers with malignancy and prognosis in canine cancer. Plasma levels of YKL-40 in healthy dogs (n = 20) and in dogs (n = 82) with cancer were evaluated using enzyme-linked immunosorbent assay. Our results indicated that plasma YKL-40 levels were significantly higher (p < 0.01) in dogs with cancer than in healthy dogs. A significant decrease in the YAA titers was detected in the dogs with cancer when compared with those of the healthy dogs (p < 0.05), although the change was not correlated with the YKL-40 levels. Among the dogs with cancer, plasma YKL-40 levels in the dogs that later relapsed or had metastasis were significantly higher than in the dogs with no signs of relapse (p < 0.01) or metastasis (p < 0.05). The relapse and metastasis rates were significantly higher in the high YKL-40 group (> 180 pg/mL) than in the low YKL-40 group (< 180 pg/mL). The results imply that plasma YKL-40 levels might have the potential to be developed as a marker of malignancy progression and prognosis in canine cancers.

Cyclical Annealing Technique To Enhance Reliability of Amorphous Metal Oxide Thin Film Transistors.

This study introduces a cyclical annealing technique that enhances the reliability of amorphous indium-gallium-zinc-oxide (a-IGZO) via-type structure thin film transistors (TFTs). By utilizing this treatment, negative gate-bias illumination stress (NBIS)-induced instabilities can be effectively alleviated. The cyclical annealing provides several cooling steps, which are exothermic processes that can form stronger ionic bonds. An additional advantage is that the total annealing time is much shorter than when using conventional long-term annealing. With the use of cyclical annealing, the reliability of the a-IGZO can be effectively optimized, and the shorter process time can increase fabrication efficiency.

Effectiveness of air purifier on health outcomes and indoor particles in homes of children with allergic diseases in Fresno, California: A pilot study.

OBJECTIVE: Epidemiologic studies indicate that indoor air pollution is correlated with morbidity caused by allergic diseases. We evaluated the effectiveness of reducing the levels of indoor fine particulate matter <2.5 micrometer diameter (PM2.5) in Fresno, California using air purifiers on health outcomes in children with asthma and/or allergic rhinitis. METHODS: The active group (with air purifiers) and the control group consisted of eight houses each. Air purifiers were installed in the living rooms and bedrooms of the subjects in the active group during the entire 12-week study duration. Childhood asthma control test, peak flow rate monitoring, and nasal symptom scores were evaluated at weeks 0, 6, and 12. RESULTS: At 12 weeks, the active group showed a trend toward an improvement of childhood asthma control test scores and mean evening peak flow rates, whereas the control group showed deterioration in the same measures. Total and daytime nasal symptoms scores significantly reduced in the active group (p = 0.001 and p = 0.011, respectively). The average indoor PM2.5 concentrations reduced by 43% (7.42 to 4.28 µg/m3) in the active group (p = 0.001). CONCLUSIONS: Intervention with air purifiers reduces indoor PM2.5 levels with significant improvements in nasal symptoms in children with allergic rhinitis in Fresno.

Development of betulinic acid as an agonist of TGR5 receptor using a new in vitro assay.

BACKGROUND: G-protein-coupled bile acid receptor 1, also known as TGR5 is known to be involved in glucose homeostasis. In animal models, treatment with a TGR5 agonist induces incretin secretion to reduce hyperglycemia. Betulinic acid, a triterpenoid present in the leaves of white birch, has been introduced as a selective TGR5 agonist. However, direct activation of TGR5 by betulinic acid has not yet been reported. METHODS: Transfection of TGR5 into cultured Chinese hamster ovary (CHO-K1) cells was performed to establish the presence of TGR5. Additionally, TGR5-specific small interfering RNA was employed to silence TGR5 in cells (NCI-H716 cells) that secreted incretins. Uptake of glucose by CHO-K1 cells was evaluated using a fluorescent indicator. Amounts of cyclic adenosine monophosphate and glucagon-like peptide were quantified using enzyme-linked immunosorbent assay kits. RESULTS: Betulinic acid dose-dependently increases glucose uptake by CHO-K1 cells transfected with TGR5 only, which can be considered an alternative method instead of radioligand binding assay. Additionally, signals coupled to TGR5 activation are also increased by betulinic acid in cells transfected with TGR5. In NCI-H716 cells, which endogenously express TGR5, betulinic acid induces glucagon-like peptide secretion via increasing calcium levels. However, the actions of betulinic acid were markedly reduced in NCI-H716 cells that received TGR5-silencing treatment. Therefore, the present study demonstrates the activation of TGR5 by betulinic acid for the first time. CONCLUSION: Similar to the positive control lithocholic acid, which is the established agonist of TGR5, betulinic acid has been characterized as a useful agonist of TGR5 and can be used to activate TGR5 in the future.

Measuring Indoor Air Quality and Engaging California Indian Stakeholders at the Win-River Resort and Casino: Collaborative Smoke-Free Policy Development.

Most casinos owned by sovereign American Indian nations allow smoking, even in U.S. states such as California where state laws restrict workplace smoking. Collaborations between casinos and public health workers are needed to promote smoke-free policies that protect workers and patrons from secondhand tobacco smoke (SHS) exposure and risks. Over seven years, a coalition of public health professionals provided technical assistance to the Redding Rancheria tribe in Redding, California in establishing a smoke-free policy at the Win-River Resort and Casino. The coalition provided information to the casino general manager that included site-specific measurement of employee and visitor PM2.5 personal exposure, area concentrations of airborne nicotine and PM2.5, visitor urinary cotinine, and patron and staff opinions (surveys, focus groups, and a Town Hall meeting). The manager communicated results to tribal membership, including evidence of high SHS exposures and support for a smoke-free policy. Subsequently, in concert with hotel expansion, the Redding Rancheria Tribal Council voted to accept a 100% restriction of smoking inside the casino, whereupon PM2.5 exposure in main smoking areas dropped by 98%. A 70% partial-smoke-free policy was instituted ~1 year later in the face of revenue loss. The success of the collaboration in promoting a smoke-free policy, and the key element of air quality feedback, which appeared to be a central driver, may provide a model for similar efforts.

Determining PM2.5 calibration curves for a low-cost particle monitor: common indoor residential aerosols.

Real-time particle monitors are essential for accurately estimating exposure to fine particles indoors. However, many such monitors tend to be prohibitively expensive for some applications, such as a tenant or homeowner curious about the quality of the air in their home. A lower cost version (the Dylos Air Quality Monitor) has recently been introduced, but it requires appropriate calibration to reflect the mass concentration units required for exposure assessment. We conducted a total of 64 experiments with a suite of instruments including a Dylos DC1100, another real-time laser photometer (TSI SidePak™ Model AM-510 Personal Aerosol Monitor), and a gravimetric sampling apparatus to estimate Dylos calibration factors for emissions from 17 different common indoor sources including cigarettes, incense, fried bacon, chicken, and hamburger. Comparison of minute-by-minute data from the Dylos with the gravimetrically calibrated SidePak yielded relationships that enable the conversion of the raw Dylos particle counts less than 2.5 µm (in #/0.01 ft(3)) to estimated PM2.5 mass concentration (e.g. µg m(-3)). The relationship between the exponentially-decaying Dylos particle counts and PM2.5 mass concentration can be described by a theoretically-derived power law with source-specific empirical parameters. A linear relationship (calibration factor) is applicable to fresh or quickly decaying emissions (i.e., before the aerosol has aged and differential decay rates introduce curvature into the relationship). The empirical parameters for the power-law relationships vary greatly both between and within source types, although linear factors appear to have lower uncertainty. The Dylos Air Quality Monitor is likely most useful for providing instantaneous feedback and context on mass particle levels in home and work situations for field-survey or personal awareness applications.

Extracellular superoxide dismutase ameliorates streptozotocin-induced rat diabetic nephropathy via inhibiting the ROS/ERK1/2 signaling.

AIM: Diabetic nephropathy is the leading cause of end stage renal disease in developed countries throughout the world. The imbalance between the production of reactive oxygen species (ROS) and the antioxidant defense system is the main problem that is responsible for the progression of diabetic kidney disease. In this study, we investigated whether human extracellular superoxide dismutase (hEC-SOD) can prevent diabetic nephropathy in the rat model. MAIN METHODS: Diabetic nephropathy symptoms were induced by intraperitoneal injection with 60 mg/kg streptozotocin (STZ) in male Sprague-Dawley (SD) rats. After daily supplement of rhEC-SOD (3200 U/kg/day) for 4 weeks, the serum or urine biochemical markers (glucose, creatinine, blood urea nitrogen, triglyceride, hemoglobin A1c, and microalbuminuria), histological changes, gene expressions (phox47, opn, and gapdh), and protein levels (TGF-ß, AT1-R, phospho-p42/p44 MAPK, and p42/p44 MAPK) were determined. KEY FINDINGS: Results showed that rhEC-SOD administration could reverse SOD activity measured in kidney and diabetic-associated changes, including the fibrosis change, expression of collagen I, transforming growth factor-beta (TGF-ß) and angiotensin II type I receptor (AT1-R), as well as the activation of the intracellular mitogen-activated protein kinase (MAPK) signaling pathway, associating with its inhibition of p42(MAPK)/p44(MAPK) (ERK1/2) phosphorylation. Additionally, diabetic nephropathy up-regulated the expression of the phox47 and opn genes, and these changes could also be suppressed. Though the proteinuria did not significantly reduce. Treatment with rhEC-SOD ameliorates STZ-induced diabetic nephropathy, leading to reduced death rates, kidney weight/body weight ratio, fibrosis change, and TGF-ß1 expression through the down-regulation of ROS/ERK1/2 signaling pathway. SIGNIFICANCE: We conclude that rhEC-SOD can act as a therapeutic agent to protect the progression of diabetic nephropathy.

Outdoor fine and ultrafine particle measurements at six bus stops with smoking on two California arterial highways--results of a pilot study.

UNLABELLED: As indoor smoking bans have become widely adopted, some U.S. communities are considering restricting smoking outdoors, creating a need for measurements of air pollution near smokers outdoors. Personal exposure experiments were conducted with four to five participants at six sidewalk bus stops located 1.5-3.3 m from the curb of two heavily traveled California arterial highways with 3300-5100 vehicles per hour. At each bus stop, a smoker in the group smoked a cigarette. Gravimetrically calibrated continuous monitors were used to measure fine particle concentrations (aerodynamic diameter < or = 2.5 microm; PM2.5) in the breathing zones (within 0.2 m from the nose and mouth) of each participant. At each bus stop, ultrafine particles (UFP), wind speed, temperature, relative humidity, and traffic counts were also measured. For 13 cigarette experiments, the mean PM2.5 personal exposure of the nonsmoker seated 0.5 m from the smoker during a 5-min cigarette ranged from 15 to 153 microg/m3. Of four persons seated on the bench, the smoker received the highest PM2.5 breathing-zone exposure of 192 microg/m3. There was a strong proximity effect: nonsmokers at distances 0.5, 1.0, and 1.5 m from the smoker received mean PM2.5 personal exposures of 59, 40, and 28 microg/m3, respectively, compared with a background level of 1.7 microg/m3. Like the PM2.5 concentrations, UFP concentrations measured 0.5 m from the smoker increased abruptly when a cigarette started and decreased when the cigarette ended, averaging 44,500 particles/cm3 compared with the background level of 7200 particles/cm3. During nonsmoking periods, the UFP background concentrations showed occasional peaks due to traffic, whereas PM2.5 background concentrations were extremely low. The results indicate that a single cigarette smoked outdoors at a bus stop can cause PM2.5 and UFP concentrations near the smoker that are 16-35 and 6.2 times, respectively, higher than the background concentrations due to cars and trucks on an adjacent arterial highway. IMPLICATIONS: Rules banning smoking indoors have been widely adopted in the United States and in many countries. Some communities are considering smoking bans that would apply to outdoor locations. Although many measurements are available of pollutant concentrations from secondhand smoke at indoor locations, few measurements are available of exposure to secondhand smoke outdoors. This study provides new data on exposure to fine and ultrafine particles from secondhand smoke near a smoker outdoors. The levels are compared with the exposure measured next to a highway. The findings are important for policies that might be developed for reducing exposure to secondhand smoke outdoors.

Stochastic modeling of short-term exposure close to an air pollution source in a naturally ventilated room: an autocorrelated random walk method.

For an actively emitting source such as cooking or smoking, indoor measurements have shown a strong "proximity effect" within 1 m. The significant increase in both the magnitude and variation of concentration near a source is attributable to transient high peaks that occur sporadically-and these "microplumes" cause great uncertainty in estimating personal exposure. Recent field studies in naturally ventilated rooms show that close-proximity concentrations are approximately lognormally distributed. We use the autocorrelated random walk method to represent the time-varying directionality of indoor emissions, thereby predicting the time series and frequency distributions of concentrations close to an actively emitting point source. The predicted 5-min concentrations show good agreement with measurements from a point source of CO in a naturally ventilated house-the measured and predicted frequency distributions at 0.5- and 1-m distances are similar and approximately lognormal over a concentration range spanning three orders of magnitude. By including the transient peak concentrations, this random airflow modeling method offers a way to more accurately assess acute exposure levels for cases where well-defined airflow patterns in an indoor space are not available.

Real-time particle monitor calibration factors and PM2.5 emission factors for multiple indoor sources.

Indoor sources can greatly contribute to personal exposure to particulate matter less than 2.5 µm in diameter (PM2.5). To accurately assess PM2.5 mass emission factors and concentrations, real-time particle monitors must be calibrated for individual sources. Sixty-six experiments were conducted with a common, real-time laser photometer (TSI SidePak™ Model AM510 Personal Aerosol Monitor) and a filter-based PM2.5 gravimetric sampler to quantify the monitor calibration factors (CFs), and to estimate emission factors for common indoor sources including cigarettes, incense, cooking, candles, and fireplaces. Calibration factors for these indoor sources were all significantly less than the factory-set CF of 1.0, ranging from 0.32 (cigarette smoke) to 0.70 (hamburger). Stick incense had a CF of 0.35, while fireplace emissions ranged from 0.44-0.47. Cooking source CFs ranged from 0.41 (fried bacon) to 0.65-0.70 (fried pork chops, salmon, and hamburger). The CFs of combined sources (e.g., cooking and cigarette emissions mixed) were linear combinations of the CFs of the component sources. The highest PM2.5 emission factors per time period were from burned foods and fireplaces (15-16 mg min(-1)), and the lowest from cooking foods such as pizza and ground beef (0.1-0.2 mg min(-1)).

Measurement of the proximity effect for indoor air pollutant sources in two homes.

Personal exposure to air pollutants can be substantially higher in close proximity to an active source due to non-instantaneous mixing of emissions. The research presented in this paper quantifies this proximity effect for a non-buoyant source in 2 naturally ventilated homes in Northern California (CA), assessing its spatial and temporal variation and the influence of factors such as ventilation rate on its magnitude. To quantify how proximity to residential sources of indoor air pollutants affects human exposure, we performed 16 separate monitoring experiments in the living rooms of two detached single-family homes. CO (as a tracer gas) was released from a point source in the center of the room at a controlled emission rate for 5-12 h per experiment, while an array of 30-37 real-time monitors simultaneously measured CO concentrations with 15 s time resolution at radial distances ranging from 0.25-5 m under a range of ventilation conditions. Concentrations measured in close proximity (within 1 m) to the source were highly variable, with 5 min averages that typically varied by >100-fold. This variability was due to short-duration (<1 min) pollutant concentration peaks ("microplumes") that were frequently recorded in close proximity to the source. We decomposed the random microplume component from the total concentrations by subtracting predicted concentrations that assumed uniform, instantaneous mixing within the room and found that these microplumes can be modeled using a 3-parameter lognormal distribution. Average concentrations measured within 0.25 m of the source were 6-20 times as high as the predicted well-mixed concentrations.

Determination of response of real-time SidePak AM510 monitor to secondhand smoke, other common indoor aerosols, and outdoor aerosol.

The amount of light scattered by airborne particles inside an aerosol photometer will vary not only with the mass concentration, but also with particle properties such as size, shape, and composition. This study conducted controlled experiments to compare the measurements of a real-time photometer, the SidePak AM510 monitor (SidePak), with gravimetric mass. PM sources tested were outdoor aerosols, and four indoor combustion sources: cigarettes, incense, wood chips, and toasting bread. The calibration factor for rescaling the SidePak measurements to agree with gravimetric mass was similar for the cigarette and incense sources, but different for burning wood chips and toasting bread. The calibration factors for ambient urban aerosols differed substantially from day to day, due to variations in the sources and composition of outdoor PM. A field evaluation inside a casino with active smokers yielded calibration factors consistent with those obtained in the controlled experiments with cigarette smoke.

Modeling exposure close to air pollution sources in naturally ventilated residences: association of turbulent diffusion coefficient with air change rate.

For modeling exposure close to an indoor air pollution source, an isotropic turbulent diffusion coefficient is used to represent the average spread of emissions. However, its magnitude indoors has been difficult to assess experimentally due to limitations in the number of monitors available. We used 30-37 real-time monitors to simultaneously measure CO at different angles and distances from a continuous indoor point source. For 11 experiments involving two houses, with natural ventilation conditions ranging from <0.2 to >5 air changes per h, an eddy diffusion model was used to estimate the turbulent diffusion coefficients, which ranged from 0.001 to 0.013 m² s⁻¹. The model reproduced observed concentrations with reasonable accuracy over radial distances of 0.25-5.0 m. The air change rate, as measured using a SF6 tracer gas release, showed a significant positive linear correlation with the air mixing rate, defined as the turbulent diffusion coefficient divided by a squared length scale representing the room size. The ability to estimate the indoor turbulent diffusion coefficient using two readily measurable parameters (air change rate and room dimensions) is useful for accurately modeling exposures in close proximity to an indoor pollution source.

Fine particle air pollution and secondhand smoke exposures and risks inside 66 US casinos.

Smoking bans often exempt casinos, exposing occupants to fine particles (PM(2.5)) from secondhand smoke. We quantified the relative contributions to PM(2.5) from both secondhand smoke and infiltrating outdoor sources in US casinos. We measured real-time PM(2.5), particulate polycyclic aromatic hydrocarbons (PPAH), and carbon dioxide (CO(2)) (as an index of ventilation rate) inside and outside 8 casinos in Reno, Nevada. We combined these data with data from previous studies, yielding a total of 66 US casinos with smoking in California, Delaware, Nevada, New Jersey, and Pennsylvania, developing PM(2.5) frequency distributions, with 3 nonsmoking casinos for comparison. Geometric means for PM(2.5) were 53.8 µg/m(3) (range 18.5-205 µg/m(3)) inside smoking casinos, 4.3 µg/m(3) (range 0.26-29.7 µg/m(3)) outside those casinos, and 3.1 µg/m(3) (range 0.6-9 µg/m(3)) inside 3 nonsmoking casinos. In a subset of 21 Reno and Las Vegas smoking casinos, PM(2.5) in gaming areas averaged 45.2 µg/m(3) (95% CI, 37.7-52.7 µg/m(3)); adjacent nonsmoking casino restaurants averaged 27.2 µg/m(3) (95% CI, 17.5-36.9 µg/m(3)), while PM(2.5) outside the casinos averaged 3.9 µg/m(3) (95% CI, 2.5-5.3 µg/m(3)). For a subset of 10 Nevada and Pennsylvania smoking casinos, incremental (indoor-outdoor) PM(2.5) was correlated with incremental PPAH (R(2)=0.79), with ventilation rate-adjusted smoker density (R(2)=0.73), and with smoker density (R(2)=0.60), but not with ventilation rates (R(2)=0.15). PPAH levels in 8 smoking casinos in 3 states averaged 4 times outdoors. The nonsmoking casinos' PM(2.5) (n=3) did not differ from outdoor levels, nor did their PPAH (n=2). Incremental PM(2.5) from secondhand smoke in approximately half the smoking casinos exceeded a level known to produce cardiovascular morbidity in nonsmokers after less than 2h of exposure, posing acute health risks to patrons and workers. Casino ventilation and air cleaning practices failed to control secondhand smoke PM(2.5). Drifting PM(2.5) from secondhand smoke contaminated unseparated nonsmoking areas. Smoke-free casinos reduced PM(2.5) to the same low levels found outdoors.

Measurement of fine particles and smoking activity in a statewide survey of 36 California Indian casinos.

Despite California's 1994 statewide smoking ban, exposure to secondhand smoke (SHS) continues in California's Indian casinos. Few data are available on exposure to airborne fine particles (PM2.5) in casinos, especially on a statewide basis. We sought to measure PM2.5 concentrations in Indian casinos widely distributed across California, exploring differences due to casino size, separation of smoking and non-smoking areas, and area smoker density. A selection of 36 out of the 58 Indian casinos throughout California were each visited for 1-3 h on weekend or holiday evenings, using two or more concealed monitors to measure PM2.5 concentrations every 10 s. For each casino, the physical dimensions and the number of patrons and smokers were estimated. As a preliminary assessment of representativeness, we also measured eight casinos in Reno, NV. The average PM2.5 concentration for the smoking slot machine areas (63 µg/m³) was nine times as high as outdoors (7 µg/m³), whereas casino non-smoking restaurants (29 µg/m³) were four times as high. Levels in non-smoking slot machine areas varied: complete physical separation reduced concentrations almost to outdoor levels, but two other separation types had mean levels that were 13 and 29 µg/m³, respectively, higher than outdoors. Elevated PM2.5 concentrations in casinos can be attributed primarily to SHS. Average PM2.5 concentrations during 0.5-1 h visits to smoking areas exceeded 35 µg/m³ for 90% of the casino visits.

Comparison and characterization of the antioxidant potential of 3 wild grapes--Vitis thunbergii, V. flexuosa, and V. kelungeusis.

UNLABELLED: This study considers a laboratory examination of the antioxidant performance of methanolic extracts from the leaves and stems of 3 common wild grapes (Vitis thunbergii, V. flexuosa, and V. kelungeusis) by various in vitro methods. It also seeks to identify the specific antioxidant constituent. Results revealed that, of these specimens, stem extracts of V. thunbergii exhibited good 1,1-diphenyl-2-picrylhydrazyl radical-scavenging and superoxide radical-scavenging performance and ferrous ion-chelating ability, as well as the highest total phenolic content (179.5 mg of GAE/g). The principal antioxidant, (+)-lyoniresinol-2a-O-ß-D-glucopyranoside, was isolated from the stem extracts of V. thunbergii and identified. Removal of this compound from the extracts caused an approximate 2- to 5-fold decrease in antioxidant performance. This showed that (+)-lyoniresinol-2a-O-ß-D-glucopyranoside is the primary antioxidant in wild grapes. Results also indicated that the antioxidant performance of (+)-lyoniresinol-2a-O-ß-D-glucopyranoside was stronger than its lignan aglycone, (+)-lyoniresinol. PRACTICAL APPLICATION: Of the 3 common wild grapes-Vitis thunbergii, V. flexuosa, and V. kelungeusis, the extracts or phytochemicals, derived from the V. thunbergii stems have excellent antioxidant properties, so they have great potential as a basis for natural health products that seek to prevent diseases caused by the overproduction of radicals.

Model-based reconstruction of the time response of electrochemical air pollutant monitors to rapidly varying concentrations.

Electrochemical sensors are commonly used to measure concentrations of gaseous air pollutants in real time, especially for personal exposure investigations. The monitors are small, portable, and have suitable response times for estimating time-averaged concentrations. However, for transient exposures to air pollutants lasting only seconds to minutes, a non-instantaneous time response can cause measured values to diverge from actual input concentrations, especially when the pollutant fluctuations are pronounced and rapid. Using 38 Langan carbon monoxide (CO) monitors, which can be set to log data every 2 s, we found electrochemical sensor response times of 30-50 s. We derived a simple model based on Fick's Law to reconstruct a close to accurate time series from logged data. Starting with experimentally measured data for repetitive step input signals of alternating high and low CO concentrations, we were able to reconstruct a much improved 2-s concentration time series using the model. We also utilized the model to examine errors in monitor measurements for different averaging times. By selecting the averaging time based on the response time of the monitor, the error between actual and measured pollutant levels can be minimized. The methodology presented in this study is useful when aiming to accurately determine a time series of rapidly time-varying concentrations, such as for locations close to an active point source or near moving traffic.