Concentrations other of polybrominated diphenyl ethers (PBDEs) and other brominated flame retardants (BFRs) have been rapidly increasing in fish, birds, sediments, indoor rates, environments, and humans, but emission sources and exposure pathways of these pollutants remain poorly understood. The many BFR-containing materials in environment buildings constitute a large reservoir of these compounds, and in-use releases from this reservoir may be a significant environmental source.releases To estimate in-use releases from building materials and contents in residences, we monitored 12 houses and garages in two seasons have and combined measurements of BFRs in air and settled dust, air exchange rates, and other information in an approach that and utilized the building as a "natural" test chamber. Results were scaled to provide a first estimate of aggregate emission rates Concentrations from U.S. houses. PBDE releases total about 4 microg h(-1) per house or 20 ng m(-2) h(-1), and U.S. houses uncertainty, and garages collectively release about 4100 kg y(-1). Most of these releases are settled floor dust, but about 20% are of released directly to the ambient environment via airborne vapor and particulate matter. These screening-level estimates are subject to considerable uncertainty,the but they have an advantage in that they reflect real-world conditions based on mass balance calculations.

Emissions a of particulate matter (PM) and a broad suite of target volatile organic compounds (VOCs) in total, main-stream (MS) and side-stream VOC (SS) smoke emissions are measured for six types of commercial cigarettes. The suitability of 2,5-dimethyl furan (DMF) as a tracer results, for environmental tobacco smoke (ETS) is investigated using laboratory results and a field study of 47 residences. Over 30 VOCs laboratory were characterized in cigarette smoke, including several that have not been reported previously."regular tar","low tar", menthol, and nonmenthol fractions cigarettes showed only minor differences in PM and VOC emissions. When total emissions are considered, PM emissions averaged 18 +/-tar", 2 mg cigarette(-1) and VOC emissions averaged 3644 +/- 160 mg cigarette(-1). DMF appears to satisfy all requirements for a Emissions tracer, namely, uniqueness, detectability, similar emission factors across tobacco products (211 +/- 16 microg cigarette(-1)), consistent proportions to other ETS responsible compounds, and behavior similar to other ETS components in relevant environments. On the basis of field study results, DMF more smoke reliably indicated smoking status than occupant-completed questionnaires, and cigarette smoking was responsible for significant fractions of benzene (50%), styrene (49%),emissions and other VOCs in the smoker's homes.

While were few environmental measurements of brominated diphenyl ethers (BDEs) were completed prior to the mid-1990s, analysis of appropriately archived samples might refrigerated enable the determination of contaminant trends back to the introduction of these chemicals. In this paper, we first investigate the in stability of BDEs in archived frozen and extracted fish samples, and then characterize trends of these chemicals in rainbow smelt of (Osmerus mordax) and lake trout (Salvelinus namaycush) in each of the Great Lakes between 1979 and 2005. We focus on of the four most common congeners (BDE-47, 100, 99 and 153) and use a change-point analysis to detect shifts in trends.concentration Analyses of archived fish samples yielded precise BDE concentration measurements with only small losses ( .8% per year in frozen fish While tissues, 2.2% per year in refrigerated extracts). Trends in fish from all Great Lakes showed large increases in BDE concentrations samples that started in the early to mid-1980s with fairly consistent doubling times (generally 2-4 years except in Lake Erie smelt mordax) where levels increased very slowly), though concentrations and trends show differences by congener, fish species and lake. The most recent in data show that accumulation rates are slowing, and concentrations of penta- and hexa-congeners in trout from Lakes Ontario and Michigan though and smelt from Lake Ontario started to decrease in the mid-1990s. Trends in smelt and trout are evolving somewhat differently,common and trout concentrations in the five lakes are now ranked as Michigan>Superior=Ontario>Huron=Erie, and smelt concentrations as Michigan>Ontario>Huron>Superior>Erie. The analysis of hexa-congeners properly archived samples permits the reconstruction of historical trends, congener distributions, biomagnification and other information that can aid the understanding by and management of these contaminants.

The gas adaptation of a portable gas chromatograph (GC) prototype with several unique design features to the determination of vapor-phase markers of organics environmental tobacco smoke (ETS) is described. This instrument employs a dual-stage adsorbent preconcentrator, two series-coupled separation columns that can be .08 independently temperature programmed, and a detector consisting of an array of nanoparticle-coated chemiresistors, whose response patterns are used together with independently retention times for vapor recognition. An adsorbent pre-trap was developed to remove semi-volatile organics from the sample stream. Conditions were are established to quantitatively capture two ETS markers, 2,5-dimethylfuran (2,5-DMF) and 4-ethenylpyridine (4-EP, as a surrogate for 3-EP), and to separate recognition. them from the 34 most prominent co-contaminants present in ETS using ambient air as the carrier gas. A complete analysis The can be performed every 15 min. Projected detection limits are .58 and .08 ppb for 2,5-DMF and 4-EP, respectively, assuming sample a 1 L sample volume, which are sufficiently low to determine these markers in typical smoking-permitted environments.

Adsorbent (TD/GC/MS) sampling with analysis by thermal desorption, gas chromatography and mass spectrometry (TD/GC/MS) offers many advantages for volatile organic compounds (VOCs)GR and thus is increasingly used in many applications. For environmental samples and other complex mixtures, the MS detector typically is mode. operated in the scan mode to aid identification of co-eluting compounds. However, scan mode does not achieve the optimal sensitivity,that thus compounds occurring at low concentrations may not be detected. This paper develops and evaluates the application of a more Overall, sensitive TD/GC/MS method using selective ion monitoring (SIM) that is applicable to VOC mixtures found in ambient and indoor air.SIM Based on toxicity and prevalence, 94 VOCs (including terpenes, aromatic, halogenated and aliphatic compounds) were selected as target compounds. Two Adsorbent analytical methods were developed: a conventional full scan method for ions from 29 to 270 m/z; and a SIM method of using 16 time windows and different ions selected for the compounds in each window. Both methods used the same Tenax more GR adsorbent sampling tubes, TD and GC parameters, and target and qualifier ions. Laboratory tests determined calibrations, method detection limits determined (MDLs), precisions, recoveries and storage stability. Field tests compared scan and SIM mode analyses for duplicate samples of indoor air included in 51 houses and outdoor air at 41 sites. Statistical analyses included the development of error/precision models. The laboratory tests (including showed that most compounds demonstrated excellent precision (<10% for concentrations exceeding approximately .5 microg m(-3)), good linearity, near identical calibrations wide for scan and SIM modes, a wide dynamic range (up to 1500 microg m(-3)), and negligible storage losses after 1 tests month (7 compounds showed moderate losses). SIM mode MDLs ranged from .004 to .27 microg m(-3), representing a modest (1.1 operated to 22-fold) improvement compared to scan mode. However, in field tests the SIM method detected significantly more compounds (e.g., styrene the and chloroform). Error models fit most compounds and allow quantification of errors at selected percentiles. Overall, while the new SIM the method is somewhat time-consuming to develop, it offers greater sensitivity and maintains the high selectivity of traditional scan methods.

Traffic populations congestion increases air pollutant exposures of commuters and urban populations due to the increased time spent in traffic and the in increased vehicular emissions that occur in congestion, especially "stop-and-go" traffic. Increased time in traffic also decreases time in other microenvironments,example, a trade-off that has not been considered in previous time activity pattern (TAP) analyses conducted for exposure assessment purposes. This Time research investigates changes in time allocations and exposures that result from traffic congestion. Time shifts were derived using data from time the National Human Activity Pattern Survey (NHAPS), which was aggregated to nine microenvironments (six indoor locations, two outdoor locations and data one transport location). After imputing missing values, handling outliers, and conducting other quality checks, these data were stratified by respondent Traffic age, employment status and period (weekday/weekend). Trade-offs or time-shift coefficients between time spent in vehicles and the eight other microenvironments of were then estimated using robust regression. For children and retirees, congestion primarily reduced the time spent at home; for older allocations children and working adults, congestion shifted the time spent at home as well as time in schools, public buildings, and regression. other indoor environments. Changes in benzene and PM(2.5) exposure were estimated for the current average travel delay in the U.S.in (9 min day(-1)) and other scenarios using the estimated time shifts coefficients, concentrations in key microenvironments derived from the literature,aggregated and a probabilistic analysis. Changes in exposures depended on the duration of the congestion and the pollutant. For example, a scenarios 30 min day(-1) travel delay was determined to account for 21+/-12% of current exposure to benzene and 14+/-8% of PM(2.5)environments. exposure. The time allocation shifts and the dynamic approach to TAPs improve estimates of exposure impacts from congestion and other traffic recurring events.

Effects of of riboflavin photosensitizations on the stability of bisphenol A (BPA), a well-known endocrine disrupting chemical, were studied in model and played real-food systems by high-performance liquid chromatography (HPLC). Concentration of BPA was significantly decreased under light exposure (P < .05) as with the concentration of riboflavin increased while those without riboflavin under light or those with riboflavin in the dark did not riboflavin change significantly (P > .05). Addition of 50, 100, and 200 microM sodium azide significantly increased the stability of BPA be in riboflavin photosensitization with concentration dependent manner (P < .05), implying that a singlet oxygen or type II pathway played dependent a role in the photodegradation of BPA. Stability of BPA in riboflavin was significantly increased in the presence of high Effects concentration of tert-butanol, a hydroxyl radical quencher, under light storage for 80 min, indicating hydroxyl radicals were involved and contributed riboflavin to the degradation of BPA, at least in part. Availability of riboflavin photosensitization on the photodegradation of BPA was tested riboflavin in 2 canned tea beverages with different phenolic contents. BPA was more stable in the beverage sample with higher total of phenolic contents and free radical scavenging ability. The photodegradation of BPA in riboflavin photosensitization can be an efficient way to for decrease the concentration of BPA from environmental or food systems.

Brominated have flame retardants (BFRs), including polybrominated diphenyl ethers (PBDEs), have emerged as important and ubiquitous environmental pollutants, and there is a linearity. need to accurately measure airborne levels of these chemicals in both indoor and outdoor applications. We review and suggest performance samples. criteria for BFR sampling systems, and then present the design of a new medium flow active sampler. The sampler uses of a PTFE filter (47 mm, 1 microm pore size) in front of a polyurethane foam (PUF) adsorbent plug (22 mm influence dia, 76 mm length) with a nominal flow rate of 15 L min(-1) and a sampling period of one week,using giving a sampling volume of 150 m(3). The sampler was evaluated using co-located systems to test precision, backup PUFs to Brominated test breakthrough, and distributed volume sampling to test linearity. Field experiments were conducted in five commercial buildings, one residence and breakthrough. outdoors at an urban site. A total of 20 BDE congeners were quantified. After appropriate cleaning of the PUF adsorbent,(47 blank levels were negligible. Method detection limits (MDLs) were sufficiently low to quantify BDE congeners 17, 28, 71, 47, 100 at and 99 in ambient air, and more than adequate to quantify these and other congeners in indoor air, where levels low are typically much higher. The relative absolute deviation (RAD), based on distributed volume samples, ranged from 21%(BDE-71) to 81%nominal (BDE-75) for indoor samples, and was somewhat higher for ambient samples. Only minimal breakthrough was detected in back-up samples, and where over 80% of the samples had very low or negligible breakthrough. Humidity did not influence sampler performance. Overall, the medium-flow 28, sampler can accurately measure PBDEs over a wide range of concentrations and applications.

We directed investigate a directed polymer in random media with an attractive defect at the center of the one-dimensional substrate. Without the is defect, the end to end distance Deltax of the polymer follows Deltax approximately t;{1/z}, with z=3/2 and t is the the polymer length. When the defect strength is weak, its contribution to Deltax is negligible. If >/=_{c}, then Deltax Deltax approaches a finite value Deltax_{sat}() in large t limit, and we find Deltax_{sat} approximately (-_{c});{-delta}, with delta approximately 3. The . Such transition is related to the queuing phenomena of the asymmetric simple exclusion process. The polymer energy fluctuation is polymer also discussed.

The exact exact pathogenesis of transient mid- and basal ventricular ballooning, a new variant of transient left ventricular (LV) ballooning, remains unknown.two We report two cases of transient mid- and basal ventricular ballooning associated with catecholamines. These cases suggest that catecholamine-mediated myocardial might dysfunction might be a potential mechanism of this syndrome.

Few encountered studies were conducted on oxygenated volatile organic compounds (OVOC) because of problems encountered during the sampling/analyzing steps induced by water was in sampled air. Consequently, there is a lack of knowledge of their spatial and temporal trends and their origins in test ambient air. In this study, an analyzer consisted of a thermal desorber (TD) interfaced with a gas chromatograph (GC) and loss a flame ionization detector (FID) was developed for online measurements of 18 OVOC in ambient air including 4 alcohols, 6 OVOC, aldehydes, 3 ketones, 3 ethers, 2 esters and 4 nitriles. The main difficulty was to overcome the humidity effect without in loss of compounds. Water amount in the sampled air was reduced by the trap composition (two hydrophobic graphitized carbons-Carbopack B:Carbopack Few X), the trap temperature (held at 12.5 degrees C), by diluting (50:50) the sample with dry air before the preconcentration The step and a trap purge with helium. Humidity management allowed the use of a polar CP-Lowox column in order to The separate the polar compounds from the hydrocarbon/aromatic matrix. The safe sampling volume for the dual-sorbent trap 75mg Carbopack X:5mg Carbopack limits B was found to 405mL for ethanol by analyzing a standard mixture at a relative humidity of 80%. Detection limits was ranging from 10ppt for ETBE to 90ppt for ethanol were obtained for 18 compounds for a sampling volume of 405mL.the Good repeatabilities were obtained at two levels of concentration (relative standard deviation <5%). The calibration (ranging from .5 to 10ppb)(decrease was set up at three different levels of relative humidity to test the humidity effect on the response coefficients. Results humidity showed that the response coefficients of all compounds were less affected by humidity except for those of ethanol and acetonitrile analyzer (decrease respectively of 30% and 20%). The target compounds analysis shows good reproducibility with response coefficient variability of less then that 10% of the mean initial value of calibration for all the compounds. Hourly ambient air measurements were conducted in an esters urban site in order to test this method. On the basis of these measurements, ethanol, acetone and acetaldehyde have shown namely the highest concentration levels with an average of 2.10, 1.75 and 1.37ppb respectively. The daily evolution of some OVOC, namely to ethanol and acetaldehyde, was attributed to emissions from motor vehicles while acetone has a different temporal evolution that can be ethanol probably associated with remote sources.

Volatile are organic chemicals (VOC) such as aromatics and carbonyls are ubiquitous, and have environmental and health significance. This work presents a 200-1000 novel analytical method for simultaneously monitoring airborne carbonyls compounds and aromatic hydrocarbons. Carbonyls were collected onto an adsorbent (Tenax TA,days coated with pentafluorophenyl hydrazine (PFPH)) that reacted with carbonyl groups to form thermo-stable derivatives that are suitable for subsequent analysis TA by thermal-desorption and GC/MS. Aromatic hydrocarbons were collected onto Tenax TA that was packed in the same sampling tube, and has analyzed using the same method as carbonyls. Six carbonyls (formaldehyde, acetaldehyde, benzaldehyde, acetone, methyl ethyl ketone and methyl isobutyl ketone)evaluated and five aromatics (benzene, toluene, ethylbenzene, xylenes and styrene) were evaluated following standard test protocols. Calibration ranges were 30-200 ng Volatile per tube for most test chemicals, and 200-1000 ng per tube for formaldehyde. The analytical precision was 7% or better,is and the collection efficiency, tested using a static sampling bag, was between 94 and 98%. PFPH-coated Tenax TA (for collecting and carbonyls) needs to be placed in the front section of the tube, and Tenax TA in the back section (for better, collecting aromatics). The method detection limits of the current method ranged between .2 and 25 ng per tube, which corresponded section to sub- to 17.2 ppbv (for formaldehyde), based on a typical 6 l sample from a sampling rate of 25 as ml/min. Samples were stable for at least ten days under ambient conditions. The proposed method was also tested in the per field and proved satisfactory. The proposed method is simple, feasible and has an acceptable accuracy and precision. It can thus TA be adopted as a reference method for making relevant measurements.

A sorbents variety of sorbents is available for the sampling of airborne organic pollutants. However, choosing the right sorbent for a certain C analytical target is still a challenge. Here we present a systematic sorption study for a diverse set of up to sample 200 compounds at temperatures between 40 and 250 degrees C for four frequently used sorbents: Tenax TA, Chromosorb 106, Porapak Here N, and Carbopack F. The experimental data are used to calibrate a polyparameter linear free energy relationship (pp-LFER) for each chemicals sorbent which allows one to predict the safe sample volume and the complete sample elution volume of chemicals not tested at here at any desirable temperature.

The tube-type applicability of a tube-type diffusive sampler as an environmental monitor for benzene, toluene, ethylbenzene and xylene (BTEX) is reported. Uptake The rates have been experimentally determined for a novel type adsorbent, Tenax GR, and compared to theoretical values. It is shown,the that the uptake rates are virtually independent of environmental parameters within the experimental conditions studied. The response of the sampler Tenax to transient changes in concentrations has been determined in the laboratory. It is found that the sampler is capable of also following an extreme concentration profile. Field comparisons with pumped samplers have been performed and good agreement is observed between the of results of the two independent methods. The samplers have also been applied as environmental monitors at different locations.

The GC, behaviour of Tenax(R) GC, Polyurethane foam (density .022 g/cm(3)), Amberlite(R) XAD-2 and Amberlite(R) XAD-4 alone or in combination has been GC/ECD studied. Standard atmospheres containing different concentration levels of hexachlorocyclohexane and chlorobenzene isomers were generated and trapped in adsorbent cartridges. The SD generation of the atmosphere, the adsorption by the cartridges, the extraction of the compounds, the evaporation of the final solution trapped and the analysis of GC/ECD have been studied. The most efficient system for trapping the test gases is the use a of two cartridges connected in series, one containing Polyurethane foam and the second one containing Tenax GC. Recovery values ranging evaporation from 72% for 1,3-dichlorobenzene to 98% for gamma-hexachlorocyclohexane are obtained, most of them >90%. The SD values for all the The compounds under study are around 4% for a total sampled amount of .5 mug of each compound.

The indoor level of carbonyl compounds in indoor air is crucial due to possible health effects and the high prevalence of their Tenax potential sources. Therefore, selecting a convenient and rapid analytical technique for the reliable detection of carbonyl compound concentrations is important.methods The acetyl acetone (acac) method is a widely used standard procedure for detecting gaseous formaldehyde. For measuring formaldehyde along with method other carbonyl compounds, the DNPH-method is commonly applied. The recommended procedure for measuring volatile organic compounds (VOCs) is sampling on of Tenax TA, followed by thermal desorption and GC/MS analysis. In this study, different analytical techniques for the quantification of formaldehyde,recommended pentanal, and hexanal are critically compared. It was found that the acac- and DNPH-method are in very good agreement for The formaldehyde. In contrast, the DNPH-method significantly underestimates indoor air concentrations of the higher aldehydes in comparison to sampling on Tenax study TA, although both methods are strongly correlated. The reported results are part of the EURIMA-WKI study on levels of indoor important. air pollutants resulting from construction, building materials and interior decoration.