商业步行街的构成手法

以金桥流通中心为例,提出了以单元模块形成的街巷空间为母题,通过多样的组合方式,来形成室外立体商业步行街的构成手法,探讨了以中庭为核心,来构成室内立体商业步行街的设计方法,由此得出现代商业步行街立体化模式的一种创作手法。     

新街坊健康住宅的硬件环境

以胶州市新街坊住宅小区为俐，从生理需求和心理需求两个方面，探讨了住宅小区在硬件环境上满足健康住宅的要求，指出住区中的物业管理及服务和文化环境将日趋完善。     

The influence of soil remediation on lead in house dust

Lead in house dust has long been recognized as a principal source of excess lead absorption among children at the Bunker Hill Superfund Site (BHSS) in northern Idaho. House dust lead concentration from homeowner's vacuum cleaner bags has been monitored since the epidemic of childhood lead poisoning in 1974. Geometric mean house dust lead concentrations decreased from >10000 mg/kg in 1974 to approximately 4000 mg/kg in 1975, in response to air pollution control initiatives at the defective primary lead smelter. After smelter closure, 1983 mean dust lead concentrations were near 3000 mg/kg and were most dependent on soil sources. Following emergency soil removals from public areas and roadsides and fugitive dust control efforts in the mid-1980s, house dust lead decreased by approximately 40-60% to 1200-1500 mg/kg. In 1992, a cleanup goal of 500 mg/kg dust lead community average, with no individual home exceeding 1000 mg/kg, was adopted. This goal was to be achieved by a combination of contaminated soil removals and fugitive dust control efforts throughout the 21 square mile BHSS. Continual reductions in house dust lead concentrations have been noted throughout the residential area soil cleanup. Geometric mean house dust lead concentrations averaged approximately 500-600 mg/kg from 1996 to 1999 and dropped below 500 mg/kg in 2000. Analysis of these data indicates that approximately 20% of the variance in dust lead concentrations is attributed to yard, neighborhood, and community soil lead concentrations. Since 1996, dust lead concentrations and dust and lead loading rates have also been measured by dust mats placed at entryways into the homes. Neighborhood soil lead concentrations, household hygiene, the number of adults living in the home, and the number of hours a child spends outdoors in summer explain approximately 26% of the variance in mat dust lead loading rates. It is estimated that post-remedial house dust lead concentrations will stabilize at 400-500 mg/kg, as compared to approximately 200 mg/kg in socio-economically similar background communities; the difference possibly attributed to residual soil concentrations (3-6 times background), recontamination of rights-of-way, tracking of non-residential mining district soils and dusts, fugitive dusts associated with the remediation, and residual structural or carpet dusts.     

Measured concentrations of consumer product chemicals in California house dust: Implications for sources,exposure, and toxicity potential

Household dust is a reservoir of various consumer product chemicals. Thus, characterizing comprehensive chemical profiles of house dust may help improve our understanding of residential chemical exposure. We have previously developed a method for detecting a broad spectrum of chemicals in dust by applying a combination of target, suspect screening, and non-target methods with mass spectrometry preceded by liquid chromatography and gas chromatography. Building upon a previous study that detected 271 compounds in 38 dust samples, we presented concentrations of 144 compounds that were confirmed and quantified by standards in the same set of samples. Ten compounds were measured with median concentrations greater than 10 000 ng/g of dust: cis-hexadec-6-enoic acid, squalene, cholesterol, vitamin E, bis(2-ethylhexyl) phthalate, dioctyl terephthalate, linoleic acid, tricaprylin, tris(1-chloroisopropyl) phosphate, and oxybenzone. We also reviewed in vitro toxicity screening data to identify compounds that were not previously detected in indoor dust but have potential for adverse health effects. Among 119 newly detected compounds, 13 had endocrine-disrupting potential and 7 had neurotoxic potential. Toxicity screening data were not available for eight biocides, which may adversely affect health. Our results strive to provide more comprehensive chemical profiles of house dust and identified information gaps for future health studies.     

Size dependent elemental composition of road-associated particles

Stormwater particles often provide transport for metals and other contaminants, however only larger particles are effectively removed by typical best management practices. Fine particles and their associated constituents are more likely to reach receiving waters; this merits further investigation regarding the metal contribution of fine (d(p)<10 microm) and very fine (d(p)<1.5 microm) particles. Road associated particles were collected by vacuuming a road surface and by collecting highway stormwater runoff. A cell sorter was employed to sort road associated particles into four size ranges: 0.1-0.3, 0.3-0.5, 0.5-1.0, and 1.0-1.5 microm. These very fine particles, along with six particle size ranges (total range <2-63 microm) separated using a settling column, were analyzed for Al, Mn, Fe, Cr, Ni, Cu, Zn, and Pb using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Enrichment factors (EFs), calculated using Al as a basis to represent crustal contributions, were similar for the vacuumed road dust and the stormwater runoff. Fe and Mn were minimally depleted (0.1x) or near unity for all size ranges (Fe EF range 0.01-3.7; Mn EF range 0.02-10.6). Cr, Ni, Cu, Zn, and Pb were moderately (10x) to considerably (>100x) enriched for most size ranges; these metals were most enriched in the very fine fractions (max EF ~ 4900 in Zn, 0.1-0.3 microm). Based on this preliminary study, a cell sorter is an acceptable means of fractionating aqueous particles of diameter 0.1-1.5 microm. In spite of their minimal relative mass contribution, the very fine particles are environmentally relevant due to their mobility and enrichment in potentially toxic metals.     

Microbial content of house dust samples determined with qPCR

This study was designed to produce information about microbial concentrations using qPCR and their variation in different seasons and home environments with analyses of two types of house dust samples. Also the correlations between the two types of samples and the reproducibility of the parallel subsamples were studied. Two types of vacuumed house dust samples, rug dust and vacuum cleaner bag dust, were collected in 5 normal urban homes in four different seasons (N = 20 + 20). From all dust samples, five parallel subsamples were subjected to qPCR analyses of 17 microbial species or assay groups of microbes. The highest fungal concentrations were found for the Penicillium/Aspergillus/Paecilomyces variotii group, and for the species Aspergillus penicillioides, Aureobasidium pullulans, Cladosporium cladosporioides and Cladosporium herbarum. These species/groups were present in almost all samples. The two types of dust samples gave similar results for most microbial species or groups analyzed, but in general, concentrations were slightly higher in rug dust than in dust from vacuum cleaner bag. Microbial concentrations varied significantly between different seasons and hence the similarity of samples within home was mainly low. The concentrations varied significantly also between different home environments. The reproducibility of the parallel subsamples was good or moderate for most of the analyzed species or assay groups. However, further studies are needed to fully understand the factors causing variation in these methods. Nevertheless, in order to show actual differences in fungal concentrations between urban homes with no known microbial sources, all dust samples to be compared should be taken during the same season.     

Relationship between the presence of newborn and the house dust endotoxin

Background

Exposure to house dust endotoxin induces of airways' inflammation. Endotoxin are produced by the Gram-negative bacteria, which are released into the stools and could contaminate domestic environment.

Objective

The newborn could contaminate his mattress by endotoxin.

Methods

The dusts of mattress and carpets of 97 newborn' dwellings were sampled at birth and after six months of life. Samplings were made in the bedroom from the baby and in the second place where the baby spent the longer time. The endotoxin concentration was measured by a quantitative Limulus assay and the bacterial contamination was evaluated using 3 selective agar media.

Results

Endotoxin concentration at birth was positively associated with the presence of both sibling and the number of inhabitants (p < 0.01). At 6 months of life, the endotoxin concentration raised significantly not only in the mattresses (from a median of 17.6 (ranges: 0.4-346.7) to 79.6 (3.8-518.8) EU/mg) (p < 0.0001), but also in the dust from the second place where the baby is sleeping (from 20.4 (0.8-226.3) to 101.8 (6.5-634.3) EU/mg) (p < 0.001). Importantly, there was no change in endotoxin concentration from the carpets dust, and the environmental dwelling characteristics remained unchanged. The total bacterial contamination was also positively associated with endotoxin concentration in newborn mattress at birth (p < 0.01) and showed a significant increase at 6 months of life of the newborn (p < 0.01).

Conclusion

The newborn is a significant source of house dust's endotoxin.     

Lead and cadmium composition in indoor dust

Pb and Cd levels in different size fractions of indoor dust have been analyzed by differential pulse anodic stripping voltammetry (DPASV) after digestion with HNO₃ and HF using a microwave oven. The relationship between Pb and Cd levels with dust size have been investigated and the metal levels in different sources of indoor dust are compared. In addition, the Pb and Cd composition in different size fractions of dust have been investigated by a sequential extraction method. Dusts are dominated by particulate matter < 500 μm. Pb levels in office dust in the particulate fraction > 75 μm are clearly shown to be higher than that in domestic dust. Generally, for domestic premises, Pb and Cd levels increase with a decrease in the particle size and with an increase in house age, while for office dust, the Pb level increases with an increase of particle size. For domestic houses, most of the metals are bound to carbonate and FeMn oxides in fine dust. For office dust, the situation is more complicated, with a clear increase in Pb in the organic and residue fractions in coarse dust.     

Streptomycetes in house dust: associations with housing characteristics and endotoxin

In addition to mold, indoor bioaerosols also contain bacterial components that may have implications for human health. Endotoxin is a cell wall component in Gram-negative bacteria present at varying levels indoors that has been found to have respiratory health implications. Streptomyces is a large genus of Gram-positive bacteria, and some species have been shown to produce inflammatory reactions in vitro and in vivo. The aim of this study was to determine predictors of streptomycetes levels in house dust and to compare the variation in streptomycetes levels with that in endotoxin levels. Dust was collected by floor vacuuming from 178 homes in the Cincinnati metropolitan area. Streptomycetes levels were measured by quantitative PCR, and endotoxin was assayed by the Limulus amebocyte lysate method. Associations between home characteristics and bacterial contaminants, expressed as concentration and load, were investigated through multiple regression analyses. The presence of two or more dogs was a strong predictor of both streptomycetes and endotoxin levels. Season of dust collection and levels of outdoor molds were predictors of streptomycetes but not endotoxin levels. In contrast, number of inhabitants was a significant predictor of endotoxin load only. Neither streptomycetes nor endotoxin levels were associated with metrics of moisture damage.     

Temporal and spatial differences in the elemental composition of atmospheric aerosols

Proton induced X-ray emission has been applied to the analysis of various elements in 250 aerosol loaded filter samples collected daily over a period of up to 3 months at different sites: (1) city-center; (2) residential area; (3) recreation area 20 km off city; and (4) remote alpine resort areas. The time dependence of different element concentrations shows high correlation with meteorological parameters. The average concentration ratio between site 1 and site 4 amounts up to 100.     

Levels of polybrominated diphenyl ethers in house dust in Central Poland

Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in numerous products, from which they are emitted to the environment, including house dust. House dust is a source of human exposure to these compounds by ingestion. The aim of this article was to determine the levels of selected PBDEs in the house dust and indicate their potential sources of origin. PBDE congeners: BDE‐47, BDE‐99, BDE‐153 and BDE‐209, were analyzed in 129 samples. The geometric mean levels (and 95% CIs) of the aforementioned congeners amounted to 3.8 (3.1–4.7) ng/g, 4.5 (3.5–5.6) ng/g, 2.2 (2.1–2.4) ng/g and 345 (269–442) ng/g respectively. BDE‐209 was the dominant congener in the majority of tested samples. We found a statistically significant correlation between the concentrations of BDE‐47 and the computer operating time per day (r_s – 0.18) and the living area (r_s – 0.20). Statistically significant higher levels of BDE‐99 were found in homes where the floor was not replaced during the last 2 years.     

Transient dispersion of dust by wind from nonpoint sources

This study is concerned with unsteady dispersion of particulates from a nonpoint source such as a storage pile and has been solved analytically. The effects of the particle sizes, the heights of the emission source, wind velocity, and the ground conditions on the downwind particle concentration distribution and deposition are presented using the dust puff model. Results indicate that a significant amount of particle deposition can occur even at locations far away from the emission source. The effect of the height of emission source on the downwind particle concentration is only significant near the emission source.     

Determinants,reproducibility, and seasonal variation of ergosterol levels in house dust

This study aimed to clarify the determinants that affect the concentrations of ergosterol and viable fungi in house dust and to examine the seasonal variation and reproducibility of ergosterol concentrations indoors. In studying the determinants, dust samples from living room floors and vacuum cleaner dust bags were collected from 107 farming and 105 non‐farming homes. Ergosterol levels were determined with gas chromatography‐mass spectrometry, and the dust bag dust was cultivated for enumeration of fungal genera. Lifestyle and environmental factors, for example using of the fireplace, and visible mold observations in homes, explained 20–26% of the variation of fungal concentrations. For the reproducibility study, samples were collected from five urban homes in four different seasons. The reproducibility of ergosterol determinations within a sample was excellent (ICC = 89.8) for floor dust and moderate (ICC = 63.8) for dust bag dust, but poor when sampling the same home throughout a year (ICC = 31.3 and 12.6, respectively) due to large temporal variation in ergosterol concentrations. In conclusion, environmental characteristics only partially predicted the variation of fungal concentrations. Based on these studies, we recommend repeated sampling of dust over time if one seeks to adequately describe overall fungal levels and exposure in a home.     

Assessing allergenic fungi in house dust by floor wipe sampling and quantitative PCR

Abstract In the present study, we modified an existing surface wipe sampling method for lead and other heavy metals to create a protocol to collect fungi in floor dust followed by real‐time quantitative PCR (qPCR)‐based detection. We desired minimal inconvenience for participants in residential indoor environmental quality and health studies. Accuracy, precision, and method detection limits (MDLs) were investigated. Overall, MDLs ranged from 0.6 to 25 cell/cm² on sampled floors. Overall measurement precisions expressed as the coefficient of variation because of sample processing and qPCR ranged 6–63%. Median and maximum fungal concentrations in house dust in study homes in Visalia, Tulare County, California, were 110 and 2500 cell/cm², respectively, with universal fungal primers (allergenic and nonallergenic species). The field study indicated samplings in multiple seasons were necessary to characterize representative whole‐year fungal concentrations in residential microenvironments. This was because significant temporal variations were observed within study homes. Combined field and laboratory results suggested this modified new wipe sampling method, in conjunction with growth‐independent qPCR, shows potential to improve human exposure and health studies for fungal pathogens and allergens in dust in homes of susceptible, vulnerable population subgroups.

Practical Implications

Fungi are ubiquitous in indoor and outdoor environments, and many fungi are known to cause allergic reactions and exacerbate asthma attacks. This study established—by modifying an existing—a wipe sampling method to collect fungi in floor dust followed by real‐time quantitative PCR (qPCR)‐based detection methodologies. Results from this combined laboratory and field assessment suggested the methodology’s potential to inform larger human exposure studies for fungal pathogens and allergens in house dust as well as epidemiologic studies of children with asthma and older adults with chronic respiratory diseases.

     

Relationships between estimated flame retardant emissions and levels in indoor air and house dust

A significant number of consumer goods and building materials can act as emission sources of flame retardants (FRs) in the indoor environment. We investigate the relationship between the emission source strength and the levels of 19 brominated flame retardants (BFRs) and seven organophosphate flame retardants (OPFRs) in air and dust collected in 38 indoor microenvironments in Norway. We use modeling methods to back‐calculate emission rates from indoor air and dust measurements and identify possible indications of an emission‐to‐dust pathway. Experimentally based emission estimates provide a satisfactory indication of the relative emission strength of indoor sources. Modeling results indicate an up to two orders of magnitude enhanced emission strength for OPFRs (median emission rates of 0.083 and 0.41 μg h^?1 for air‐based and dust‐based estimates) compared to BFRs (0.52 and 0.37 ng h^?1 median emission rates). A consistent emission‐to‐dust signal, defined as higher dust‐based than air‐based emission estimates, was identified for four of the seven OPFRs, but only for one of the 19 BFRs. It is concluded, however, that uncertainty in model input parameters could potentially lead to the false identification of an emission‐to‐dust signal.     

锯齿形街沟在城市旧路改造中的应用

结合工程实例介绍了锯齿形街沟在城市旧路改造中的应用情况,着重说明了锯齿形街沟的计算过程,阐述了雨水口和分水点的设置要点,指出在旧路改造工程中采用锯齿形街沟排除路表水,相对于调整道路纵坡方案更为经济有效,值得推广应用。     

Determinants of house dust endotoxin in three European countries - the AIRALLERG study

The comparison of endotoxin levels between study populations and countries is limited as a result of differences in sampling, extraction, and storage procedures. The objective of this study is to assess the levels and determinants of endotoxin in mattress and living room floor dust samples from three European countries, namely, Germany, the Netherlands, and Sweden, using a standardized sampling, storage, and analysis protocol. The mattress and living room floor dust was collected from the homes of 1065 German, Dutch, and Swedish (pre-)school children. All the samples were collected in the cool season and analyzed for endotoxin in a central laboratory. The determinants were assessed by a standardized questionnaire. The endotoxin concentrations in mattress and living room floor dust were found to be the highest in German homes and lowest in the Swedish ones. Differences between the geometric means were small (factor 1.1-1.7). Most of the associations between endotoxin concentrations and potential determinants were not statistically significant and heterogeneous across countries. However, keeping pets and having more than four persons living in the home were consistently associated with up to 1.7-fold higher endotoxin concentrations in mattress and floor dust. Furthermore, having carpets or rugs, and opening the windows frequently was associated with up to 3.4-fold and 1.3-fold higher endotoxin concentrations in living room floor dust, respectively. The proportion of variance explained by the questionnaire variables was generally low. In conclusion, the data on housing characteristics did not accurately predict the endotoxin concentrations in house dust, and could only partly explain the differences between countries. PRACTICAL IMPLICATIONS: The differences between the endotoxin concentrations in German, Dutch, and Swedish homes are small. House dust endotoxin concentrations are associated with a number of housing factors, such as pet-ownership, floor cover, number of persons living in the home, and ventilation. The variability of the endotoxin levels between homes and countries can only be partly explained by these factors.     

Features of the elemental composition of plants of northern Western Siberian palsas

This paper reports the current state of lake and wetland ecosystems in the north of Western Siberia and describes the mechanisms of their formation and succession. Elemental composition of lake water and macrophytes of the four most typical subarctic lake ecosystems in Western Siberia were analysed using ICP MS. We selected the species of Menyanthes trifoliata L. as an example of the biogeochemical system. The general dynamics of concentration of the chemical elements in M. trifoliata L. in all four ecosystems demonstrate the minimal concentrations of rare-earth elements, of which the mobility in fresh waters and the bioavailability are low. Similar properties are exhibited by all tri and tetravalent hydrolysates. We also calculated, at each of the four stages of development of the lake ecosystems, the coefficients of biological accumulation of chemical elements by M. trifoliata L. (Kb) relative to the water. This revealed that the M. trifoliata L. strongly accumulates heavy metals, such as Pb, Zn, Sr and Co. The sources may be both global factors (atmospheric transport, water treatment, etc.) and various types of local pollution occurring as a result of anthropogenic impact on ecosystems of the north.     

Exposure to toxic agents alters organic elemental composition in human fingernails

Background and objective:

The human fingernail plate is highly keratinized. The keratin structure is held together by disulfide bonds. The organic elements sulfur and nitrogen occur almost exclusively in amino acids of the nail plate. This study analyzed whether occupational exposure to harmful chemical agents alters the organic elemental composition in fingernails.

Subjects and methods:

Participants were 71 occupationally exposed workers (49 hairdressers, 22 painters) and 49 unexposed controls. Aspects of exposure were assessed by questionnaire. Nail clippings of index and little fingers were analyzed for sulfur (S), nitrogen (N), carbon (C), and hydrogen (H) contents, using an automatic elemental analyzer (Vario EL III, Elementar Analysensysteme, Hanau, Germany). C/N, N/S, and C/S ratios were calculated. Reliability of elemental measurements was tested in a subset.

Results:

Reliability analysis of elemental measurements showed a very good agreement. Both painters and hairdressers displayed in their fingernails significantly lower percentages of sulfur, but higher percentages of carbon than unexposed controls. A trend was observed in that sulfur content was lowest in those hairdressers who reported structural changes in their fingernails. As a consequence, the C/S and N/S ratios were significantly increased in both exposed groups.

Conclusion:

The occupational use of harmful substances leads to decreased sulfur levels in the exposed persons, probably due to diminution of sulfur-rich proteins in the nails, resulting from destruction of disulfide-bonds by alkaline and acid groups. Thus, the C/S ratio seems to be a useful indicator for the amount of damage of nail protein by harmful agents.