Buffer Distance Research Articles

Fragmented landscapes affect honey bee colony strength at diverse spatial scales in agroecological landscapes in Kenya.

Landscape fragmentation and habitat loss at multiple scales directly affect species abundance, diversity, and productivity. There is a paucity of information about the effect of the landscape structure and diversity on honey bee colony strength in Africa. Here, we present new insights into the relationship between landscape metrics such as patch size, shape, connectivity, composition, and configuration and honey bee (Apis mellifera) colony strength characteristics. Remote-sensing-based landscape variables were linked to honey bee colony strength variables in a typical highly fragmented smallholder agroecological region in Kenya. We examined colonies in six sites with varying degrees of land degradation during the period from 2017 to 2018. Landscape structure was first mapped using medium resolution bitemporal Sentinel-1 and Sentinel-2 satellite imagery with an optimized random forest model. The influence of the surrounding landscape matrix was then constrained to two buffer distances, i.e., 1 km representing the local foraging scale and 2.5 km representing the wider foraging scale around each investigated apiary and for each of the six sites. The results of zero-inflated negative binomial regression with mixed effects showed that lower complexity of patch geometries represented by fractal dimension and reduced proportions of croplands were most influential at local foraging scales (1 km) from the apiary. In addition, higher proportions of woody vegetation and hedges resulted in higher colony strength at longer distances from the apiary (2.5 km). Honey bees in moderately degraded landscapes demonstrated the most consistently strong colonies throughout the study period. Efforts towards improving beekeeper livelihoods, through higher hive productivity, should target moderately degraded and heterogeneous landscapes, which provide forage from diverse land covers.

GIS Based Analysis of Niger-Benue River Flood Risk and Vulnerability of Communities in Kogi State, Nigeria

Flood remains one of the most common natural disasters. Its rate of occurrence and the associated destructive tendency are on a rising scale across the globe. Flood risk may increase due to human activities. It could also decrease by appropriate flood management and planning. However, this requires upgraded and newly generated reliable and up to date floodplain and flood vulnerability maps. Hence, this study analysed the Niger-Benue river flood risk and vulnerability of 256 communities in Kogi State. The aim is to generate reliable up to date flood vulnerability maps that categorises the communities into different vulnerability zones and identify likely locations for erecting flood shelter/refugee camps during flood events in the State. Shuttle Radar Topography Mission (STRM) Digital Elevation Datasets, the spatial location of 256 communities, shapefiles of Kogi State’s administrative boundaries and Niger-Benue river basin were among the datasets acquired for the study. The Digital Elevation Model (DEM) of the study area was created to depict topography and the heights of each component of the terrain. Also, a 3km buffer distance was created around the Niger-Benue river and four vulnerability zones were defined based on the terrain and proximity components of each community. Furthermore, choropleth maps were generated for each vulnerability zone based on the number of communities per Local Government Area (LGA). Findings of this study revealed that out of the 256 sampled communities, 161 representing 62.89% are exposed to varying degrees of vulnerability due to Niger-Benue flooding. Out of these, 33 (12.89%) are highly vulnerable, whereas each of the vulnerable (64) and marginally vulnerable (64) communities accounted for 25%. The rest 37.11% constituted the not vulnerable communities (95). Out of the highly vulnerable communities, 27.27% accounted for those located on river banks and 72.73% for those located within a 3km distance from the river. The majority of the riverbank communities were found in Kogi, Lokoja and Ajaokuta LGAs. Igalamela Odolu, Kogi, Ofu and Bassa were among the LGAs with a high number of vulnerable communities. The not vulnerable communities were mostly located around the Agbaja Plateau and Okoro-Agbo hills in Ijumu, Kabba/Bunu and Yaba East LGAs. It was concluded that the 9 communities (Ajaokuta, Eroko, Iche, Jamata, Numai, Okume, Agodo, Denbor and Gunji Twaki) located on river banks are exposed to the highest level of flood risk and invariably, the devastating impact of flood in Kogi State. Most communities in Ijumu, Kabba/Bunu and Yaba West LGAs are less likely to be affected by Niger-Benue River flooding. It is therefore recommended that communities within the highly vulnerable zones, beginning with the 9 located on river banks should be relocated to higher terrains. Also, future settlement development should be discouraged in the zone by the collaborative efforts of the State and LGA authorities. Further studies should be conducted around Ijumu LGA in view of identifying the most suitable locations for possible flood shelter/refugee camp development in the study area.

Response of eelgrass (Zostera marina) to an adjacent Olympia oyster restoration project.

Recent restoration efforts for the native Olympia oyster, Ostrea lurida, are commonly motivated by potential return of oyster-associated ecosystem services, including increased water filtration. The potential impact of such restoration on another species of ecological concern, eelgrass, Zostera marina, is unclear, but has been hypothesized to be positive if oyster filter feeding increases light penetration to eelgrass. For two years after construction of an oyster restoration project, we assessed the response of adjacent eelgrass (impact) compared to control and reference eelgrass beds by monitoring changes in light intensity, eelgrass shoot density, biomass, leaf morphometrics, and epiphyte load. We observed lower light intensity consistently over time, including prior to restoration, near the constructed oyster bed relative to the control and one of the reference locations. We also observed minor variations between control and impact eelgrass morphology and density. However, the changes observed were not outside the range of natural variation expected in this system, based upon comparisons to reference eelgrass beds, nor were they detrimental. This limited impact to eelgrass may be due in part to the incorporation of a buffer distance between the restored oyster bed and the existing eelgrass bed, which may have dampened both positive and negative impacts. These findings provide evidence that Olympia oyster restoration and eelgrass conservation goals can be compatible and occur simultaneously.

Estimation of thermodynamic and dynamic contributions to sea ice growth in the Central Arctic using ICESat-2 and MOSAiC SIMBA buoy data

The fine spatial resolution of the ICESat-2 (IS2) satellite altimeter allows monitoring the evolution of sea ice thickness with detailed dynamic information (e.g. ridges and leads). In this study, we first assess the ability of IS2 to estimate thermodynamic ice growth and dynamic thickening during the ice-growing season in the central Arctic Ocean. As an indicator of the thermodynamic ice growth, we use 10 thermistor string-based sea ice mass balance array (SIMBA) buoys deployed at a scale of ~50 km from the Icebreaker Polarstern during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. We collect IS2 data within 20 km buffer distance from the individual buoys, and calculate the mode, median, and mean of the IS2-derived ice thickness. The IS2 modal thickness shows the least bias (−0.169 m) with the buoy ice thickness, representing level ice thickness. In addition, the increasing rate of the IS2 modal thickness is close to the thermodynamic ice growth with a small bias of −0.054 cm/day. However, the increasing rates of the IS2 median and mean thickness are greater than the thermodynamic ice growth by about 0.114 cm/day and 0.198 cm/day, respectively, because they also include ice growth caused by thickness redistribution during dynamic deformation. The dynamic contributions may account for 26.1 ± 10.3% and 34.4 ± 10.1% of the total increase of the IS2 median and mean thickness, respectively. Within a ~ 50 km radius area from the MOSAiC Central Observatory, IS2 measurements exhibit that the ridge fraction increased from <2% in November to ~4% in March (~0.029%/day of average increasing rate) and ridge height increased about 0.047 cm/day during the same period. However, lead formation does not show significant contributions to the dynamic ice thickening because leads are temporary features lasting only 2–3 days. Although there are considerable uncertainties in IS2 ice thickness estimation and IS2-buoy thickness comparison, this study emphasizes the importance of combining measurements by IS2 and SIMBA buoys to explain the regional sea ice mass balance with separating the thermodynamic and dynamic contributions.

A field spray drift study to determine the downwind effects of isoxaflutole herbicide to nontarget plants.

Spray drift buffers are often required on herbicide labels to prevent potential drift effects to nontarget plants. Buffers are typically derived by determining the distance at which predicted exposure from spray drift equals the ecotoxicology threshold for sensitive plant species determined in greenhouse tests. Field studies performed under realistic conditions have demonstrated, however, that this approach is far more conservative than necessary. In 2016, the US Environmental Protection Agency estimated that isoxaflutole (IFT), a herbicide used to control grass and broadleaf weeds, could adversely affect downwind nontarget dicot plants at distances of ≥304 m from the edge of the treated field due to spray drift. This prediction implies that a buffer of at least 304 m is required to protect nontarget plants. To refine the predicted buffer distance for IFT, we conducted a field study in which sensitive nontarget plants (lettuce and navy bean, two to four leaf stage) were placed at various distances downwind from previously harvested soybean fields sprayed with Balance® Flexx Herbicide. The test plants were then transported to a greenhouse for grow out following the standard vegetative vigor test protocol. There were three trials. One had vegetation in the downwind deposition area (i.e., test plants placed in mowed grass; typical exposure scenario) and two had bare ground deposition areas (worst‐case exposure scenario). For both plant species in bare ground deposition areas, effects on shoot height and weight were observed at 1.52 m but not at downwind distances of ≥9.14 m from the edge of the treated area. No effects were observed at any distance for plants placed in the vegetated deposition area. The field study demonstrated that a buffer of 9.14 m protects nontarget terrestrial plants exposed to IFT via spray drift even under worst‐case conditions. Integr Environ Assess Manag 2022;18:757–769. © 2021 Bayer. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Geological and Geospatial Mapping of Vulnerability Areas for Proper Flood Mitigation: Ganaja, Lokoja Metropolis, North-Central Nigeria

This study aimed at the geological and geospatial mapping of flood vulnerable areas in Ganaja, Lokoja metropolis for proper flood mitigation. The geological mapping of the study area involved taking several traverses and understudying the different rock types in the study area. Rocks identified are porphyritic granite, migmatite, augen gneiss, aplitic granite, medium-grained granite, pegmatitic intrusions and quartzo-feldspathic veins, banded gneiss and biotite gneiss. Fractures and joint within the rocks show NW-SE, NNE-SSW orientations; corresponding to the predominant stress direction that represent imprints of the Pan-African orogeny. The incessant inundation of the settlement by floods has necessitated this risk and vulnerability assessment. Results from the geospatial investigation identified three areas with respect to vulnerability level. Buildings within 100 meters buffer distance from the river banks and flood plains are highly vulnerable, those within 200 meters buffer distance is moderately vulnerable while those 300 meters above buffer distance are less vulnerable areas. The relationship between the geology or geomorphology of the area and its effect on flood vulnerability is clearly seen from the geologic, elevation and vulnerability maps of the study area. The contour intervals in the western section is seen to have steeper slopes thereby allowing for easy run-off while the eastern section, having the flood plains of River Niger; have more gentle slopes with a tendency to accumulate water.

Environmental Impact Assessment (EIA) Using Geographical Information System (GIS): An Integrated Land Suitability Analysis of Filling Stations

A stable methodology for conserving the natural environment has been a concern for developing countries. The fast-paced growth of urbanization generated significant demand for automobiles, leading to greater utilization of fuel. The consumption of fuel is fulfilled by the Filling Station (FS). An FS is undoubtedly an important facility, but it is reported that it has high potential for degradation of natural resources, pollution problems, environmental degradation, and hydrological, geological, and socio-economic hazards, and therefore the site selection of such facilities is an essential problem. The traditional approach utilizes EIA assessments and GIS separately and existing models lacks integration. Thus, this study provides an integrated GIS-based land suitability modeling using EIA assessments, and the Analytic Hierarchy Process (AHP) has been used as key land use feature prioritization for the appropriate selection of FS locations. A case study is also carried out to assess the precision of the suggested model. The findings indicate that more than 73% of the present FS are in the acceptable region, while 27% of the FS are not in the adequate region using the local code. Furthermore, 58% of the present FS are in the acceptable region, while 42% of current FS are not in the adequate region using the international code. The findings of the comparative code analysis show a difference in the codes. The international code looks safer compared to the local code because it has higher buffer distances. This model will assist decision-makers in making better decisions for such land suitability problems for filling stations, and this model can also be extended to other facilities by some modifications in the filters and data layers of the model.

Associations between Vehicle Miles Traveled and Ambient Air Pollution at Regulatory Monitoring Sites: A Natural Experiment using the COVID-19 Shutdown

BACKGROUND AND AIM: Transportation planners calculate vehicle miles traveled (VMT) to forecast roadway usage and inform policy decisions. However, the relationship between VMT and ambient air pollution is not fully understood. In this analysis, we use proprietary smartphone sensing data with VMT calculations to examine the impact of VMT on ambient air pollution during the decline in vehicle usage from the COVID-19 shutdown. We aim to determine how VMT change contributes to change in NO2, O3, and PM2.5 concentrations and at what spatial scale these changes occur. METHODS: We obtained access to a daily national database with VMT calculations for January to July 2020, which corresponds to various stay at home orders that limited travel needs. We linked VMT measures at different buffer distances (100, 300, 500, 1000, 2000 and 3000m) to ambient air pollution monitor from the Environmental Protection Agency (EPA). We implement multi-level linear regression models to examine how NO2, O3, and PM2.5 changed with VMT reductions in different distance buffers around monitoring locations. RESULTS:Preliminary results show consistent associations between VMT and O3 and NO2 at varying buffer distances, but these associations are less consistent for PM2.5. For O3, we observe a 0.18 ppb (95% CI: -0.21, -0.15) reduction per 1,000 VMT at the 100m buffer but this reduction increases to 0.47 ppb (95% CI: 0.52, 0.43) at the 3,000m buffer. For NO2, we observe a 2.21 ppb (95% CI: 2.13, 2.30) increase per 1,000 VMT at the 100m buffer and results are similar out to the 3,000m buffer. When we split out VMT by road type, we find that models for VMT from expressways yield smaller magnitudes of association than the models for VMT from non-expressways. CONCLUSIONS:These results will be used to inform future analyses on how congestion reduction projects impact local air pollution and population health. KEYWORDS: Traffic-related, Policy research, Exposure assessment-air pollution, Oxides of nitrogen, Particle components, Ozone

Response of phosphorus in estuaries to soil erosion – A new insight into sediment phosphorus fractions and sources

Phosphorus (P) is a chemical element that can cause lake eutrophication, tracing the source of P in lake sediments is crucial in the management and control of nutrient discharges in a watershed. To combine watersheds with lakes and provide watershed surface feature support for the traceability of sediment P fractions, the estuary was used as the key location collecting sediments. The Revised Universal Soil Loss Equation was used to simulate the spatiotemporal distribution characteristics of soil erosion, the relationship between sediment P fractions to soil erosion was analyzed for different watersheds and buffer zones, thus revealing the mechanism of this relationship. The proportion of P fractions first respond to the manner of P loss in a watershed, then the factors affecting the sediment P fractions are determined. When calcium-bound P (Ca-P) accounted for more than 40% total P (TP), forest land soil erosion plays an important role in increasing the proportion of Ca-P in sediment, the correlation coefficient can reach 0.66 when the soil erosion in mountainous area is large. When P bound by iron oxides or hydroxides (Fe-P) and aluminum-bound P (Al-P) were the main components of TP in sediment, the P fractions in the sediment is affected complexly. The phosphate fertilizer application and arable land soil erosion increased the Fe-P and Al-P contents in sediments. As the buffer distance increased, the correlation coefficient between soil erosion modulus and Fe-P showed a decreasing trend. The adsorption capacity of the sediments for P was influenced by water quality, which led to changes in Fe-P and Al-P contents of sediments over time. Main findingsSoil erosion has an influence on the P fractions of sediments. Ca-P comes from forest land, while Fe/Al-P are active P, which are affected by phosphate fertilizer, land use, buffer distance and human activities.

Air-cooled chiller screening noise analysis with preliminary building project information

For Inter-noise 2018, the author submitted a paper proposing techniques to derive reasonable preliminary estimates of building project stationary noise emission levels from sparse but available data that may seem unrelated to noise or vibration such as gross square footage (GSF), expected occupancy, and land use or function. Results from these predictions would be used to support or refine established buffer distances between exposed outdoor heating, ventilating, and air-conditioning (HVAC) system noise sources and nearby noise-sensitive receptors, helping planners tasked with ambitious infill or growth goals better fit building projects into complicated campus development puzzles. This paper provides supplemental guidance by linking the same preliminary building project GSF, occupancy, and function information to estimates of cooling load (expressed as refrigeration tonnage) and thus an additional HVAC consideration not discussed in the author's previous study. When such refrigeration relies upon air-cooled condensers installed outdoors on building rooftops or at grade, substantial noise sources are introduced to the environment. Thus, this new study shares data and methodology to help expand the value and utility of the previous work and potentially provide more comprehensive building HVAC noise estimates for use by building developers and planners.

Association between Pesticides in House Dust and Residential Proximity to Farmland in a Rural Region of Taiwan.

Pesticide drift was reported in many international studies, but rarely studied in Taiwan. We conducted a study in a rural region of Taiwan to examine the associations between pesticides in house dust and nearby agricultural areas using geographic information system (GIS). A questionnaire regarding home characteristics and pesticide use, and indoor and outdoor dust samples were collected from 47 rural homes. Dust samples were analyzed for six pesticides, and agricultural land data for GIS analysis were retrieved from a national website. All but prallethrin were frequently detected from indoor dust samples (>50%), and the maximum concentrations were all below 1000 ng/g. Detection frequencies and concentrations of pesticides in outdoor dust samples were even lower than that in indoor dust samples. Only “work involving pesticides” in the questionnaire was significantly associated with four pesticides in house dust (p < 0.05). Carbofuran and tetramethrin in house dust were significantly correlated with rice cultivation area at certain buffer distances (ρ > 0.33, p < 0.05), and chlorpyrifos was found to be associated with abandoned cultivation area, suggesting the occurrence of pesticide drift. Despite the low levels of pesticides in house dust, residents in the rural region should be cautious of pesticide drift from nearby active or abandoned farmlands.

Ecological Status as the Basis for the Holistic Environmental Flow Assessment of a Tropical Highland River in Ethiopia

There is an increasing need globally to establish relationships among flow, ecology, and livelihoods to make informed decisions about environmental flows. This paper aimed to establish the ecological foundation for a holistic environmental flow assessment method in the Gumara River that flows into Lake Tana in Ethiopia and the Blue Nile River. First, the ecological conditions (fish, macro-invertebrate, riparian vegetation, and physicochemical) of the river system were characterized, followed by determining the hydrological condition and finally linking the ecological and hydrological components. The ecological data were collected at 30 sites along the Gumara River on March 2016 and 2020. River hydrology was estimated using the SWAT model and showed that the low flow decreased over time. Both physico-chemical and macroinvertebrate scores showed that water quality was moderate in most locations. The highest fish diversity index was in the lower reach at Wanzaye. Macroinvertebrate diversity was observed to decrease downstream. Both the fish and macroinvertebrate diversity indices were less than the expected maximum, being 3.29 and 4.5, respectively. The normalized difference vegetation index (NDVI) for 30 m and 60 m buffer distances from the river decreased during the dry season (March–May). Hence, flow conditions, water quality, and land-use change substantially influenced the abundance and diversity of fish, vegetation, and macroinvertebrate species. The pressure on the ecology is expected to increase because the construction of the proposed dam is expected to alter the flow regime. Thus, as demand for human water consumption grows, measures are needed, including quantification of environmental flow requirements and regulating river water uses to conserve the ecological status of the Gumara River and Lake Tana sub-basin.

Large conservation opportunities exist in >90% of tropic-subtropic coastal habitats adjacent to cities

Large conservation opportunities exist in >90% of tropic-subtropic coastal habitats adjacent to cities

Alert time reflects the negative impacts of human disturbance on an endangered bird species in Changbai Mountain, China

Human proximity often has negative consequences for wildlife. In response to human disturbance, animals may display a variety of potentially costly behavioural responses, such as vigilance or flight, which were often used as measures of fearfulness and to indicate varying habituation levels. With rapid human development, the globally endangered Scaly-sided Merganser (Mergus squamatus) may be vulnerable to anthropogenic interference. However, human-induced disturbances to a local breeding population have not been quantified. In this study, we tested how flight initiation distance (FID) and behavioural budget (alert time (AT) in particular) changes in relation to human presence in this species in Changbai Mountain, China. The results showed that individuals who experienced greater levels of human disturbance had shorter FIDs, which indicate that the local population may be habituated to human approach. However, this species spent more time being vigilant in its behavioral budget, which suggested that some other human-induced stimuli may impose negative effects on the species. This study will allow managers to better understand the response of this endangered species to different human-induced disturbances and provided scientific basis for local wildlife managers to establish buffer distance for SSME in Changbai Mountain.

DELINEATION OF URBAN FLOOD RISK AREAS USING GEOSPATIAL TECHNIQUE

The threat posed by urban flooding in most cities of the world is becoming alarming especially within the recent decades. This makes it necessary to Identify and delineate flood risk areas within cities in order to curb it menace. This study employs geospatial technique to delineate flood risk areas within Kano metropolis with a view to mitigating its impact on lives and properties. Digital Elevation Model (ASTER DEM 30m) was used to derive excess surface run-off attributes including flow direction and accumulation. Based on these attributes, flood risk areas were determined and delineated using buffer distances of 500 meters. World View image (30 cm spatial resolution) was used to identify the landuses at risk. The result from the analysis delineated flood risk areas at varying exposure levels (i.e high, moderate and low).It was evident that flood risk level within the metropolis corresponds to the pattern of surface run-off flow accumulation areas. Settlements and farmlands found within high accumulation areas along the floodplains of River Jakara (in the North and North-eastern part) and Kano-Zaria road (southern part) are at higher risk than those found on low accumulation areas. The study concluded that excess surface run-off flow direction and accumulation are among the fundamental factors determining the risk to urban flooding. The study recommends that with the ongoing level of urban development and impervious surface expansion, urban planners and policy makers should make use of the flow direction and accumulation maps in determining safer places for future developments

DELINEATION OF URBAN FLOOD RISK AREAS USING GEOSPATIAL TECHNIQUE

The threat posed by urban flooding in most cities of the world is becoming alarming especially within the recent decades. This makes it necessary to Identify and delineate flood risk areas within cities in order to curb it menace. This study employs geospatial technique to delineate flood risk areas within Kano metropolis with a view to mitigating its impact on lives and properties. Digital Elevation Model (ASTER DEM 30m) was used to derive excess surface run-off attributes including flow direction and accumulation. Based on these attributes, flood risk areas were determined and delineated using buffer distances of 500 meters. World View image (30 cm spatial resolution) was used to identify the landuses at risk. The result from the analysis delineated flood risk areas at varying exposure levels (i.e high, moderate and low).It was evident that flood risk level within the metropolis corresponds to the pattern of surface run-off flow accumulation areas. Settlements and farmlands found within high accumulation areas along the floodplains of River Jakara (in the North and North-eastern part) and Kano-Zaria road (southern part) are at higher risk than those found on low accumulation areas. The study concluded that excess surface run-off flow direction and accumulation are among the fundamental factors determining the risk to urban flooding. The study recommends that with the ongoing level of urban development and impervious surface expansion, urban planners and policy makers should make use of the flow direction and accumulation maps in determining safer places for future developments.

Comparing competing geospatial measures to capture the relationship between the neighborhood food environment and diet

To examine how the choice of neighborhood food environment definition impacts the association with diet. Using food frequency questionnaire data from the Reasons for Geographic and Racial Differences in Stroke study at baseline (2003-2007), we calculated participants' dietary inflammation score (DIS) (n=20,331); higher scores indicate greater pro-inflammatory exposure. We characterized availability of supermarkets and fast food restaurants using several geospatial measures, including density (i.e., counts/km2) and relative measures (i.e., percentage of all food stores or restaurants); and various buffer distances, including administrative units (census tract) and empirically derived buffers ("classic" network, "sausage" network) tailored to community type (higher density urban, lower density urban, suburban/small town, rural). Using generalized estimating equations, we estimated the association between each geospatial measure and DIS, controlling for individual- and neighborhood-level sociodemographics. The choice of buffer-based measure did not change the direction or magnitude of associations with DIS. Effect estimates derived from administrative units were smaller than those derived from tailored empirically derived buffer measures. Substantively, a 10% increase in the percentage of fast food restaurants using a "classic" network buffer was associated with a 6.3 (SE=1.17) point higher DIS (P< .001). The relationship between the percentage of supermarkets and DIS, however, was null. We observed high correlation coefficients between buffer-based density measures of supermarkets and fast food restaurants (r=0.73-0.83), which made it difficult to estimate independent associations by food outlet type. Researchers should tailor buffer-based measures to community type in future studies, and carefully consider the theoretical and statistical implications for choosing relative (vs. absolute) measures.

Types and spatial contexts of neighborhood greenery matter in associations with weight status in women across 28 U.S. communities

Excess body weight is a risk factor for many chronic diseases. Studies have identified neighborhood greenery as supportive of healthy weight. However, few have considered plausible effect pathways for ecosystem services (e.g., heat mitigation, landscape aesthetics, and venues for physical activities) or potential variations by climate. This study examined associations between weight status and neighborhood greenery that capture ecosystem services most relevant to weight status across 28 U.S. communities.Weight status was defined by body mass index (BMI) reported for 6591 women from the U.S. Sister Study cohort. Measures of greenery within street and circular areas at 500 m and 2000 m buffer distances from homes were derived for each participant using 1 m land cover data. Street area was defined as a 25 m-wide zone on both sides of street centerlines multiplied by the buffer distances, and circular area was the area of the circle centered on a home within each of the buffer distances. Measures of street greenery characterized the pedestrian environment to capture physically and visually accessible greenery for shade and aesthetics. Circular greenery was generated for comparison. Greenery types of tree and herbaceous cover were quantified separately, and a combined measure of tree and herbaceous cover (i.e., aggregate greenery) was also included. Mixed models accounting for the clustering at the community level were applied to evaluate the associations between neighborhood greenery and the odds of being overweight or obese (BMI > 25) with adjustment for covariates selected using gradient boosted regression trees. Analyses were stratified by climate zone (arid, continental, and temperate).Tree cover was consistently associated with decreased odds of being overweight or obese. For example, the adjusted odds ratio [AOR] was 0.92, 95% Confidence Interval [CI]: 0.88–0.96, given a 10% increase in street tree cover at the 2000 m buffer across the 28 U.S. communities. These associations held across climate zones, with the lowest AOR in the arid climate (AOR: 0.74, 95% CI: 0.54–1.01). In contrast, associations with herbaceous cover varied by climate zone. For the arid climate, a 10% increase in street herbaceous cover at the 2000 m buffer was associated with lower odds of being overweight or obese (AOR: 0.75, 95% CI: 0.55–1.03), whereas the association was reversed for the temperate climate, the odds increased (AOR: 1.19, 95% CI: 1.05–1.35).Associations between greenery and overweight/obesity varied by type and spatial context of greenery, and climate. Our findings add to a growing body of evidence that greenery design in urban planning can support public health. These findings also justify further defining the mechanism that underlies the observed associations.

Modelling spatial population exposure and evacuation clearance time for the Auckland Volcanic Field, New Zealand

Auckland, New Zealand's largest city (population of ~1.6 million), is situated atop the monogenetic Auckland Volcanic Field (AVF). As in many places faced with volcanic activity, evacuation is seen as the best risk mitigation strategy for preserving lives in the event of volcanic unrest and/or an eruption. However, planning for an evacuation can be challenging. In particular, the uncertainty in vent location resulting from the monogenetic nature of the field makes identifying neighbourhoods to be evacuated impractical until well into the pre-eruption unrest period. This study uses spatial analysis methods to assess exposure for both population and private transport ownership as well as to identify those areas requiring public transport support for an evacuation. These data were overlaid on a range of possible vent locations across the AVF using a 500 × 500 m grid. At each possible vent location, a 5 km evacuation zone is modelled, following the official contingency plan for evacuation in a future AVF event. In order to simulate vent location uncertainty leading up to a future eruption, a range of buffer distances were applied around the modelled vent locations.The exposure data derived were then used to model evacuation clearance time, which considered four phases: 1) the time taken to decide to call an evacuation; 2) the public notification time; 3) the evacuee's time to prepare; and 4) evacuee's travel time to beyond the evacuation zone. The length of time involved in phases 1 to 3 are all independent of the vent location; our analysis found these phases could be completed within 36 h, with over 80% confidence. Travel times to beyond the evacuation zone were modelled using the exposure analysis for population and private transport ownership combined with road network data and vehicle carrying capacity. This revealed travel times for this phase ranging from less than 1 up to 11 h, depending on traffic congestion, when considering no vent uncertainty. By combining the times modelled for all four phases, we found that when there is high certainty in the vent location, the median total evacuation clearance time with no congestion is approximately 37 h. However, include a 10 km vent uncertainty buffer into the model, the evacuation clearance time can increase to between 38 and 55 h, dependent on traffic congestion. A vent in the densely populated inner Auckland and CBD area would result in the greatest population required to evacuate, and also the greatest need for public transport support given the low vehicle ownership in this area. Our results can be used to inform emergency management decision making, and the model can be adapted for other regions as well as for other hazards.

Land use regression modelling of community noise in São Paulo, Brazil

Noise pollution has negative health consequences, which becomes increasingly relevant with rapid urbanization. In low- and middle-income countries research on health effects of noise is hampered by scarce exposure data and noise maps. In this study, we developed land use regression (LUR) models to assess spatial variability of community noise in the Western Region of São Paulo, Brazil.We measured outdoor noise levels continuously at 42 homes once or twice for one week in the summer and the winter season. These measurements were integrated with various geographic information system variables to develop LUR models for predicting average A-weighted (dB(A)) day-evening-night equivalent sound levels (Lden) and night sound levels (Lnight). A supervised mixed linear regression analysis was conducted to test potential noise predictors for various buffer sizes and distances between home and noise source. Noise exposure levels in the study area were high with a site average Lden of 69.3 dB(A) ranging from 60.3 to 82.3 dB(A), and a site average Lnight of 59.9 dB(A) ranging from 50.7 to 76.6 dB(A). LUR models had a good fit with a R2 of 0.56 for Lden and 0.63 for Lnight in a leave-one-site-out cross validation. Main predictors of noise were the inverse distance to medium roads, count of educational facilities within a 400 m buffer, mean Normalized Difference Vegetation Index (NDVI) within a 100 m buffer, residential areas within a 50 m (Lden) or 25 m (Lnight) buffer and slum areas within a 400 m buffer. Our study suggests that LUR modelling with geographic predictor data is a promising and efficient approach for noise exposure assessment in low- and middle-income countries, where noise maps are not available.