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201.
In studies of coarse particulate matter (PM10-2.5), mass concentrations are often estimated through the subtraction of PM2.5 from collocated PM10 tapered element oscillating microbalance (TEOM) measurements. Though all field instruments have yet to be updated, the Filter Dynamic Measurement System (FDMS) was introduced to account for the loss of semivolatile material from heated TEOM filters. To assess errors in PM10-2.5 estimation when using the possible combinations of PM10 and PM2.5 TEOM units with and without FDMS, data from three monitoring sites of the Colorado Coarse Rural–Urban Sources and Health (CCRUSH) study were used to simulate four possible subtraction methods for estimating PM10-2.5 mass concentrations. Assuming all mass is accounted for using collocated TEOMs with FDMS, the three other subtraction methods were assessed for biases in absolute mass concentration, temporal variability, spatial correlation, and homogeneity. Results show collocated units without FDMS closely estimate actual PM10-2.5 mass and spatial characteristics due to the very low semivolatile PM10-2.5 concentrations in Colorado. Estimation using either a PM2.5 or PM10 monitor without FDMS introduced absolute biases of 2.4 µg/m3 (25%) to –2.3 µg/m3 (–24%), respectively. Such errors are directly related to the unmeasured semivolatile mass and alter measures of spatiotemporal variability and homogeneity, all of which have implications for the regulatory and epidemiology communities concerned about PM10-2.5. Two monitoring sites operated by the state of Colorado were considered for inclusion in the CCRUSH acute health effects study, but concentrations were biased due to sampling with an FDMS-equipped PM2.5 TEOM and PM10 TEOM not corrected for semivolatile mass loss. A regression-based model was developed for removing the error in these measurements by estimating the semivolatile concentration of PM2.5 from total PM2.5 concentrations. By estimating nonvolatile PM2.5 concentrations from this relationship, PM10-2.5 was calculated as the difference between nonvolatile PM10 and PM2.5 concentrations.

Implications: Errors in the estimation of PM10-2.5 concentrations using subtraction methods were shown to be related to the unmeasured semivolatile mass when using certain combinations of TEOM instruments. For the northeastern Colorado region, the absolute bias associated with this error significantly affects mean and 95th percentile values, which would affect assessment of compliance if PM10-2.5 is regulated in the future. Estimating PM10-2.5 mass concentrations using nonvolatile mass concentrations from collocated PM10 and PM2.5 TEOM monitors closely estimates the total PM10-2.5 mass concentrations. A corrective model that removes the described error was developed and applied to data from two sites in Denver.

Supplemental Materials: Supplemental materials are available for this paper. Go to the publisher's online edition of the Journal of the Air & Waste Management Association.  相似文献   
202.
The increased variability in weather as a manifestation of climate change is expected to have negative impacts on population survival in wildlife species, because it will likely lead to increased variation in vital demographic rates (mortality and reproduction) in these populations. For the effective protection of biodiversity, adaptation measures are needed to compensate for the expected increase in weather variability and the negative interaction with habitat fragmentation. As a case study, we studied the fluctuations in Great Bittern numbers (Botaurus stellaris) from 28 monitoring plots scattered over the Netherlands to explore the interaction between the effect of weather and possible remediating effects of the landscape structure. Great Bittern habitat surrounding these plots differs with respect to area, quality, and degree of isolation of this habitat. In western Europe, Great Bitterns are found to be susceptible to continuous loss of suitable habitat due to vegetation succession and fragmentation. Moreover, year-to-year fluctuations in local Great Bittern populations can be caused by severe winter weather or other weather extremes. Our results show that severe winter weather has indeed a significant negative impact on Great Bittern population growth rates. Furthermore, we found that an increased carrying capacity and spatial cohesion (i.e. inverse of habitat fragmentation) contribute to an increase in mean growth rates over the years. As growth rates are higher in large, well-connected habitats, we argue that recovery from negative effects of, e.g. severe winters on Great Bittern population numbers is enhanced in these less-fragmented habitats. We derived generic adaptation measures for enhancing the recovery rate of populations of species in general: one should invest in more large, well-connected nature areas, not only to diminish the negative effects of habitat fragmentation on wildlife populations, but additionally to reduce the impacts of climatic variability.  相似文献   
203.
Blood serum specimens from 81 non-occupationally exposed adults residing in four areas close to municipal and waste incinerators as well as metallurgical industry plant and 44 adult subjects coming from control area of Slovakia were analysed for polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (dl-PCBs) and polybrominated diphenylethers (PBDEs). The concentration of total WHO(98)TEQ PCDD/F/dl-PCBs in whole group of donors from areas where known sources causing dioxin contamination are present was significantly higher than in control group of donors (p<0.001). Correlation between the age of donors and PCDD/F and dl-PCB levels was confirmed (Spearman's r(PCDD/Fs)=0.543, r(dl-PCBs)=0.521, p<0.001). Furthermore, this study presents first results concerning the PBDE congeners in human serum of Slovak general population. The total concentration (congeners 28, 47, 99, 100, 153, 154, 183) in control group was approximately 1.5-times higher in comparison to that of residents coming from areas with supposed environmental pollution. The most abundant congeners in all samples were BDE-47 and BDE-153 with median values of 0.24 ng g(-1) lipid and 0.23ngg(-1) lipid, respectively. The positive association between PBDE values and age of donors was not found.  相似文献   
204.
In a certain area of Michalovce district in East Slovakia, heavy industrial pollution by polychlorinated biphenyls (PCBs) developed in 1955-1984 and very high PCB levels in environmental and human samples are still persisting. Recently, a total of 2045 adults from this and the surrounding background pollution area have been examined using questionnaire data, thyroid volume by ultrasound (ThV), urinary iodine and serum levels of 15 PCB congeners, hexachlorobenzene (HCB), 2,2'-2-bis(4-chlorobiphenyl)-1,1-dichloroethylene (DDE), 2,2'-bis(4-chlorophenyl)-1,1,1-trichloroethane (DDT), alpha-, beta- and gamma-hexachlorocyclohexane (HCH), thyrotropin (TSH), free thyroxine (FT4), anti-thyroperoxidase antibodies (TPOab) and fasting glucose. As based on our previous findings of strikingly high level of PCBs in fish from high pollution area (e.g. mean level of 375430 ng/g lipid) and considerably lower, but still relatively high level in background pollution area (e.g. mean PCB level of 5150 ng/g), the information on the frequency of fish meals and approximate annual consumption of fish from local waters was obtained by questionnaires. The association of contaminated fish consumption with very high blood levels of PCBs, DDE and HCB and increased ThV as well as with increased frequency of positive TPOab, high values of FT4 and impaired fasting glucose (IFG) was found. These associations were also confirmed in 16 marital pairs from high pollution area with very high PCB level in both members associated with high fish consumption. It was concluded that, due to persistent heavy pollution of waters, soil and food chain namely by PCBs, but also by pesticides (e.g. DDE and HCB) resulting from their previous extensive use in agriculture, the fish from local waters still remains the most important source of these toxic pollutants which results in considerable adverse health effects.  相似文献   
205.
Environmental Science and Pollution Research - Drinking water is one of the main contributors to overall human exposure to per- and polyfluoroalkyl substances (PFAS), a broad group of environmental...  相似文献   
206.
Environmental Chemistry Letters - Glyphosate is an herbicide which was previously considered safe for non-target organisms. 825.8&nbsp;million kilograms of glyphosate-based products were used...  相似文献   
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