Spatial and temporal variations in traffic-related particulate matter at New York City high schools

Relatively little is known about exposures to traffic-related particulate matter at schools located in dense urban areas. The purpose of this study was to examine the influences of diesel traffic proximity and intensity on ambient concentrations of fine particulate matter (PM_2.5) and black carbon (BC), an indicator of diesel exhaust particles, at New York City (NYC) high schools. Outdoor PM_2.5 and BC were monitored continuously for 4–6 weeks at each of 3 NYC schools and 1 suburban school located 40 km upwind of the city. Traffic count data were obtained using an automated traffic counter or video camera. BC concentrations were 2–3 fold higher at urban schools compared with the suburban school, and among the 3 urban schools, BC concentrations were higher at schools located adjacent to highways. PM_2.5 concentrations were significantly higher at urban schools than at the suburban school, but concentrations did not vary significantly among urban schools. Both hourly average counts of trucks and buses and meteorological factors such as wind direction, wind speed, and humidity were significantly associated with hourly average ambient BC and PM_2.5 concentrations in multivariate regression models. An increase of 443 trucks/buses per hour was associated with a 0.62 μg/m³ increase in hourly average BC at an NYC school located adjacent to a major interstate highway. Car traffic counts were not associated with BC. The results suggest that local diesel vehicle traffic may be important sources of airborne fine particles in dense urban areas and consequently may contribute to local variations in PM_2.5 concentrations. In urban areas with higher levels of diesel traffic, local, neighborhood-scale monitoring of pollutants such as BC, which compared to PM_2.5, is a more specific indicator of diesel exhaust particles, may more accurately represent population exposures.     

A critical review of hydrological data collection for assessing preservation risk for urban waterlogged archaeology: A case study from the City of York, UK

Environmental change caused by urban development, possibly augmented by climate change, may result in accelerated decay of in situ archaeological resources. Damage may be related to changes in hydrological processes. Such archaeological resources have to be considered in environmental planning. In this paper we highlight the need for improved hydrological data from urban archaeological sites using the case study of the City of York, UK, arguably one of the most well studied and well preserved urban archaeological environments globally. We suggest that the quality of hydrological data collected during routine surveys and experimental work must be improved and standardised in order for us to produce reliable archaeological risk models for urban sites.     

Perception of street vendors as ‘out of place’ urban elements at day time and night time

This study attempts to understand the public evaluation towards elements that exist within the temporal dynamics of the cities. In particular the study explores the extent to which street vendors in Jakarta are evaluated as ‘out of place’ elements at day time and night time. The findings suggest that the users' evaluation of street vendors as ‘out of place’ change from day time to night time. The change of users' evaluation also varies across different urban places. In particular the study suggests that the presence of street vendors seems to be less unacceptable (out of place) at night time. Such knowledge regarding the dynamic of ‘out of place’ evaluation becomes important in making the decision about temporary urban elements in the city.     

The relationship of place to substance use and perceptions of risk and safety in urban adolescents

Geographic and substance use data were collected from 301 urban adolescents to compare the perceived and observed risk and safety associated with their home and activity space locations (routine locations). The geographic characteristics of the neighborhood surrounding each location was summarized according to features theorized to be risky, such as criminal activity and alcohol sales, and features theorized to be safe, such as recreation centers and churches. Data on socioeconomic status, derived from U.S. Bureau of the Census data, were also used to characterize locations. Adolescents' homes were typically perceived as safe despite observed measures of risk such as density of crimes and proximity to alcohol outlets. This held for both substance users and non-users. Differences in geographic characteristics for safe and risky activity spaces were observed for both substance users and non-users, with non-users appearing to be more sensitive to the presence of risky characteristics in the environment than substance users. Results highlight the need and provide a methodology to collect fine-grained activity space data instead of relying only on home residence when attempting to represent place and health behaviors with urban youth.     

The change of European landscapes: human-nature relationships, public attitudes towards rewilding, and the implications for landscape management in Switzerland

The rewilding of landscapes is one of the most important and intensively discussed landscape changes occurring in Switzerland, as the need for agricultural and forest land is decreasing. To ensure that decisions concerning future landscape management will be supported by the public, it is crucial to take public opinion into account. Hence the present study aims to assess the public attitudes towards nature and "rewilding" processes. In order to analyze these attitudes, we sent a standardized questionnaire to 4000 randomly selected households throughout Switzerland. A cluster analysis led to a typology with four different types of human-nature relationship ("nature lovers", "nature sympathizers", "nature-connected users" and "nature controllers") that each characterize a particular attitude towards nature. These human-nature relationship types differ in their attitudes towards rewilding as well, allowing a rough classification of the sample into wilderness opponents (51.1%) and wilderness proponents (49.9%). However both groups agree with regard to their opinion concerning the rules and regulations that should apply in future wilderness areas. The parallels of the human-nature relationship typology of this survey with other typologies, and the implications for further research are discussed. We can conclude that, due to the differences concerning the attitudes towards wilderness between the human-nature relationship types, between the rural and urban dwellers, and between the language regions, a uniform strategy for the designation and management of wilderness areas in Switzerland is not possible. We recommend that, when managing landscape change, all stakeholders are included in a participatory process and we advise a thorough assessment of the attitudes of the involved persons towards nature and rewilding at the start of such processes. Such an assessment would facilitate the identification of well-defined target groups allowing specific interventions and management actions customized to the needs and characteristics of each of these groups. In addition we see the commonalities between wilderness opponents and wilderness proponents concerning the rules in wilderness areas as an ideal starting point for a successful participatory process.     

Assessing the genotoxicity of urban air pollutants using two in situ plant bioassays

Genotoxicity of urban air has been analysed almost exclusively in airborne particulates. We monitored the genotoxic effects of airborne pollutants in the urban air of Perugia (Central Italy). Two plant bioindicators with different genetic endpoints were used: micronuclei in meiotic pollen mother cells using Tradescantia-micronucleus bioassay (Trad-MCN) and DNA damage in nuclei of Nicotiana tabacum leaves using comet assay (Nicotiana-comet). Buds of Tradescantia clone # 4430 and young N. tabacum cv. Xanthi plants were exposed for 24 h at three sites with different pollution levels. One control site (indoor control) was also used. The two bioassays showed different sensitivities toward urban pollutants: Trad-MCN assay was the most sensitive, but DNA damage in N. tabacum showed a better correlation with the pollutant concentrations. In situ biomonitoring of airborne genotoxins using higher plants combined with chemical analysis is thus recommended for characterizing genotoxicity of urban air.     

Evidence for Changing Flood Risk in New England Since the Late 20th Century1

Abstract: Long‐term flow records for watersheds with minimal human influence have shown trends in recent decades toward increasing streamflow at regional and national scales, especially for low flow quantiles like the annual minimum and annual median flows. Trends for high flow quantiles are less clear, despite recent research showing increased precipitation in the conterminous United States over the last century that has been brought about primarily by an increased frequency and intensity of events in the upper 10th percentile of the daily precipitation distribution – particularly in the Northeast. This study investigates trends in 28 long‐term annual flood series for New England watersheds with dominantly natural streamflow. The flood series are an average of 75 years in length and are continuous through 2006. Twenty‐five series show upward trends via the nonparametric Mann‐Kendall test, 40% (10) of which are statistically significant (p < 0.1). Moreover, an average standardized departures series for 23 of the study gages indicates that increasing flood magnitudes in New England occurred as a step change around 1970. The timing of this is broadly synchronous with a phase change in the low frequency variability of the North Atlantic Oscillation, a prominent upper atmospheric circulation pattern that is known to effect climate variability along the United States east coast. Identifiable hydroclimatic shifts should be considered when the affected flow records are used for flood frequency analyses. Special treatment of the flood series can improve the analyses and provide better estimates of flood magnitudes and frequencies under the prevailing hydroclimatic condition.     

Flood Effects on an Alaskan Stream Restoration Project: The Value of Long‐Term Monitoring1

Densmore, Roseann V. and Kenneth F. Karle, 2009. Flood Effects on an Alaskan Stream Restoration Project: The Value of Long‐Term Monitoring. Journal of the American Water Resources Association (JAWRA) 45(6):1424‐1433. Abstract: On a nationwide basis, few stream restoration projects have long‐term programs in place to monitor the effects of floods on channel and floodplain configuration and floodplain vegetation, but long‐term and event‐based monitoring is required to measure the effects of these stochastic events and to use the knowledge for adaptive management and the design of future projects. This paper describes a long‐term monitoring effort (15 years) on a stream restoration project in Glen Creek in Denali National Park and Preserve in Alaska. The stream channel and floodplain of Glen Creek had been severely degraded over a period of 80 years by placer mining for gold, which left many reaches with unstable and incised streambeds without functioning vegetated floodplains. The objectives of the original project, initiated in 1991, were to develop and test methods for the hydraulic design of channel and floodplain morphology and for floodplain stabilization and riparian habitat recovery, and to conduct research and monitoring to provide information for future projects in similar degraded watersheds. Monitoring methods included surveyed stream cross‐sections, vegetation plots, and aerial, ground, and satellite photos. In this paper we address the immediate and outlying effects of a 25‐year flood on the stream and floodplain geometry and riparian vegetation. The long‐term monitoring revealed that significant channel widening occurred following the flood, likely caused by excessive upstream sediment loading and the fairly slow development of floodplain vegetation in this climate. Our results illustrated design flaws, particularly in regard to identification and analysis of sediment sources and the dominant processes of channel adjustment.     

Using trace element concentrations in Corbicula fluminea to identify potential sources of contamination in an urban river

We used the biomonitor, Corbicula fluminea, to investigate the contributions of trace elements associated with different point sources and land uses in a large river. Trace elements were analyzed in tissues of clams collected from 15 tributary streams draining five land use or point source types: agriculture, forest, urban, coal-fired power plant (CFPP), and wastewater (WWTP). Clams from forested catchments had elevated Hg concentrations, and concentrations of arsenic and selenium were highest (5.0+/-0.2 and 13.6+/-0.9 microg g(-1) dry mass (DM), respectively) in clams from CFPP sites. Cadmium concentrations were significantly higher in clams from urban and CFPP sites (4.1+/-0.2 and 3.6+/-0.9 microg g(-1) DM, respectively). Non-metric multidimensional scaling (NMS) of tissue concentrations in clams clustered at CFPP and forest/agriculture sites at opposite ends of the ordination space, and the distribution of sites was driven by Cu, Zn, Cd, and Hg.