We characterized the air pollution exposure of cyclists in the city center of Curitiba (Brazil) and then systematically analyzed the influence of several traffic management strategies (bus lanes, ...bicycle lanes, traffic calming area, traffic lights, and cleaner vehicle technologies) on the exposure. We focused on concentrations of particulates monitored on-board bicycles: PM2.5, black carbon mass (BC) and particle number concentration (PNC), and also reported on total volatile organic compound concentrations (TVOC). Overall, mean (± standard deviation) exposure was moderate compared to other cities around the world (BC: 6.98 ± 11.53 μg m‐−3, PM2.5: 33.22 ± 25.64 μg m−3, PNC: 3.93 × 104 ± 4.17 × 104 cm−3, TVOC: 361 ± 99 ppb). Concentrations were higher in the morning rush hour than in the afternoon traffic peak, and exhibited a large spatial variability. Bus stops and signalized traffic intersections emerged as hotspots when compared to the rest of the journey, increasing all particulate concentrations. Lower exposure was found on streets with low traffic (particularly, small number of heavy-duty vehicles) and within shallow canyon structures. The impact of traffic calming areas on cyclists' exposure is still inconclusive and further experimental and modelling studies are needed. Simple emission calculations based on traffic activity and real-world emission factors suggested that replacing the diesel bus fleet with hybrid electric buses might largely decrease (64%) the exposure to BC in the city center. Urban planners could use this valuable information to project new cycleways, which would lead to healthier active transportation. Synchronizing traffic signals might further reduce exposure at intersections.
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•We monitored traffic-related pollutant concentrations while cycling in Curitiba.•BC, PNC, PM2.5 and VOC exposure showed high spatio-temporal variability.•Proximity to signalized intersections, bus stops and deep canyons increased exposure.•The impact of traffic calming areas on particle pollution is inconclusive.•Switching from diesel to electric buses may largely reduce cyclists' exposure to BC.
Data on airborne fine particle (PM
2.5
) emissions and concentrations in cities are valuable for traffic and air quality managers, urban planners, health practitioners, researchers, and ultimately ...for legislators and decision makers. Emissions and ambient concentrations of PM
2.5
and black carbon (BC) were assessed in the city of Curitiba, southern Brazil. The methodology combined a month-long monitoring campaign with both fixed and mobile instruments, development of emission inventories, and dispersion model simulations on different scales. The mean urban background PM
2.5
concentrations during the campaign were 7.3 μg m
−3
in Curitiba city center, but three- to fourfold higher (25.3 μg m
-3
) in a residential area on the city’s outskirts, indicating the presence of local sources, possibly linked to biomass combustion. BC concentrations seemed to be more uniformly distributed over the city, with mean urban background concentrations around 2 μg m
−3
, half of which due to local traffic emissions. Higher mean BC concentrations (3–5 μg m
-3
) were found along busy roads. The dispersion modeling also showed high PM
2.5
and BC concentrations along the heavily transited ring road. However, the lack of in situ data over these peripheral areas prevented the verification of the model output. The vehicular emission factors for PM
2.5
and BC from the literature were found not to be suitable for Curitiba’s fleet and needed to be adjusted. The integrated approach of this study can be implemented in other cities, as long as an open data policy and a close cooperation among regional, municipal authorities and academia can be achieved.
Transportation: An Overview from Open Data Approach Parcianello, Yussef; Kozievitch, Nadia P.; Fonseca, Keiko V. O. ...
2018 IEEE International Smart Cities Conference (ISC2),
2018-Sept.
Conference Proceeding
The increasing urban population sets new demands for mobility solutions. The impacts of traffic congestions or inefficient transit connectivity directly affect public health (emissions, stress, for ...example) and the city economy (deaths in road accidents, productivity, commuting, etc). In parallel, the advance of technology has made it easier to obtain data about the systems which make up the city information systems. The result of this scenario is a large amount of data, growing every day and requiring effective handling in order to be transformed into integrated and useful information. This article aims to analyze the urban public transportation from the perspective of open data and data science. We focus on data integration challenges for smart city applications and present an use case of data usage to speed limit enforcement. We also present an initial comparative analysis of New York and Curitiba data collection and processing approaches. The results unveil challenges to overcome regarding file formats, reference systems, precision, accuracy and data quality, among others, that still need effective approaches to easy open data exploitation for new services. We discuss data characteristics that can possibly be used to optimize public transportation systems aiming at standards for transportation data worldwide.
Bus Rapid Transit (BRT) corridors and systems have emerged in the past three decades as affordablesolutions of medium capacity public transport services to highly urbanized areas, especially in ...LatinAmerica and Asia. In Stockholm, trunk bus lines have gained priority over mixed traffic over the yearsthrough exclusive bus lanes, signal priority, and reliability control, for example, but no complete BRTsolution has been implemented yet. Among the inner-city trunk lines, Line 4 is the most demanded witharound 70,000 passengers boarding the service daily. This thesis proposes, then, to assess theoperational impacts that BRT solutions as segregate median lanes, stations with off-board farecollection and platform level boarding and alighting through all bus doors, full signal priority andheadway control strategy, would have in bus Line 4, using a microscopic simulation approach. Twoscenarios were simulated, and the results compared to the existing conditions (Base Scenario).Scenario 1 considered a 5-minute headway service and Scenario 2, 3-minute headways. Overall, theproposed scenarios reduce travel times by 37.6-49.1%, increase average operational speeds (includingdwell times) by 60.4-96.6%, decrease dwell times by 57.9-65.6%, decrease delays by 18.4-36%,decrease vehicle occupancy rates by 3.5-44.9% and improve the Coefficient of Variation of theheadways from 0.83-0.85 in the Base Scenario to 0.1 in Scenario 1 and 0.2 in Scenario 2. As a resultof the reduction in travel times, a BRT service would need 13 buses to operate a 5-minute headwayand 21 buses for a 3-minute headway, against 27 vehicles that are used currently for a 4 to 6-minuteheadway during peak hour.
Aim: Species interaction networks are known to vary in structure over large spatial scales. We investigated the hypothesis that environmental factors affect interaction network structure by ...influencing the functional diversity of ecological communities. Notably, we expect more functionally diverse communities to form interaction networks with a higher degree of niche partitioning. Location: Americas. Time period: Current. Major taxa studied: Hummingbirds and their nectar plants. Methods: We used a large dataset comprising 74 quantitative plant–hummingbird interaction networks distributed across the Americas, along with morphological trait data for 158 hummingbird species. First, we used a model selection approach to evaluate associations between the environment (climate, topography and insularity), species richness and hummingbird functional diversity as predictors of network structure (niche partitioning, i.e., complementary specialization and modularity). Second, we used structural equation models (SEMs) to ask whether environmental predictors and species richness affect network structure directly and/or indirectly through their influence on hummingbird functional diversity. For a subset of 28 networks, we additionally evaluated whether plant functional diversity was associated with hummingbird functional diversity and network structure. Results: Precipitation, insularity and plant richness, together with hummingbird functional diversity (specifically, functional dispersion), were consistently strong predictors of niche partitioning in plant–hummingbird networks. Moreover, SEMs showed that environmental predictors and plant richness affected network structure both directly and indirectly through their effects on hummingbird functional diversity. Plant functional diversity, however, was unrelated to hummingbird functional diversity and network structure. Main conclusions: We reveal the importance of hummingbird functional diversity for niche partitioning in plant–hummingbird interaction networks. The lack of support for similar effects for plant functional diversity potentially indicates that consumer functional diversity might be more important for structuring interaction networks than resource functional diversity. Changes in pollinator functional diversity are therefore likely to alter the structure of interaction networks and associated ecosystem functions.
Functional traits can determine pairwise species interactions, such as those between plants and pollinators. However, the effects of biogeography and evolutionary history on trait‐matching and ...trait‐mediated resource specialization remain poorly understood.
We compiled a database of 93 mutualistic hummingbird–plant networks (including 181 hummingbird and 1,256 plant species), complemented by morphological measures of hummingbird bill and floral corolla length. We divided the hummingbirds into their principal clades and used knowledge on hummingbird biogeography to divide the networks into four biogeographical regions: Lowland South America, Andes, North & Central America, and the Caribbean islands. We then tested: (a) whether hummingbird clades and biogeographical regions differ in hummingbird bill length, corolla length of visited flowers and resource specialization, and (b) whether hummingbirds' bill length correlates with the corolla length of their food plants and with their level of resource specialization.
Hummingbird clades dominated by long‐billed species generally visited longer flowers and were the most exclusive in their resource use. Bill and corolla length and the degree of resource specialization were similar across mainland regions, but the Caribbean islands had shorter flowers and hummingbirds with more generalized interaction niches. Bill and corolla length correlated in all regions and most clades, that is, trait‐matching was a recurrent phenomenon in hummingbird–plant associations. In contrast, bill length did not generally mediate resource specialization, as bill length was only weakly correlated with resource specialization within one hummingbird clade (Brilliants) and in the regions of Lowland South America and the Andes in which plants and hummingbirds have a long co‐evolutionary history. Supplementary analyses including bill curvature confirmed that bill morphology (length and curvature) does not in general predict resource specialization.
These results demonstrate how biogeographical and evolutionary histories can modulate the effects of functional traits on species interactions, and that traits better predict functional groups of interaction partners (i.e. trait‐matching) than resource specialization. These findings reveal that functional traits have great potential, but also key limitations, as a tool for developing more mechanistic approaches in community ecology.
A free Plain Language Summary can be found within the Supporting Information of this article.
A free Plain Language Summary can be found within the Supporting Information of this article.
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