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Map of the study area (thick black outline). Thin black lines refer to the paths of each of the five DIYSCO2 systems. The coloured areas are the neighbourhoods used in further analysis. The location of the eddy-covariance tower and the start and end point of all paths are labelled. The 1.9 × 1.9 km box labelled “Sunset study area” refers to the domain of previous research, including the fine-scale emission inventory developed by and .
Source publication
A method for directly measuring carbon dioxide (CO2) emissions using a mobile sensor network in cities at fine spatial resolution was developed and tested. First, a compact, mobile system was built using an infrared gas analyzer combined with open-source hardware to control, georeference, and log measurements of CO2 mixing ratios on vehicles (car,...
Citations
... [70], carbon trading [29], [30], [63]- [65], [71]- [83], and carbon capture and storage (CCS) [84]. Carbon monitoring primarily focuses on measurement, reporting, and verification (MRV), often employing sensors that directly measure carbon dioxide emissions [85]. Carbon trading, on the other hand, not only promotes the monitoring of carbon emissions but also treats these emissions as tradable commodities, thereby motivating stakeholders to engage actively in emission reduction strategies. ...
Real and effective regulation of contributions to greenhouse gas emissions and pollutants requires unbiased and truthful monitoring. Blockchain has emerged not only as an approach that provides verifiable economical interactions but also as a mechanism to keep the measurement, monitoring, incentivation of environmental conservationist practices and enforcement of policy. Here, we present a survey of areas in what blockchain has been considered as a response to concerns on keeping an accurate recording of environmental practices to monitor levels of pollution and management of environmental practices. We classify the applications of blockchain into different segments of concerns, such as greenhouse gas emissions, solid waste, water, plastics, food waste, and circular economy, and show the objectives for the addressed concerns. We also classify the different blockchains and the explored and designed properties as identified for the proposed solutions. At the end, we provide a discussion about the niches and challenges that remain for future research.
... Bergeron and Strachan found a clear decrease in CO 2 fluxes from urban to suburban and agricultural areas in Montreal and concluded that the lower emissions were due to vehicular traffic contributions decreasing from 11.5 µmol m − 2 s − 1 in urban areas to 4.8 µmol m − 2 s − 1 in suburban areas (Bergeron and Strachan, 2011). Lee et al. (2017) found, using eddy covariance, that downtown areas emitted 3-5 times more CO 2 than did peripheral areas and that mixing ratios increased by 24-39 ppm from green suburban areas to downtown areas. Our study revealed an average decrease of 35 ppm in the CO 2 mixing ratio as we approached suburban areas compared to downtown areas, which was linked to this vehicular reduction occurring from urban to suburban areas. ...
Monitoring CO 2 concentrations in urban areas is crucial for determining the efficacy of climate change mitigation policies. However, highly heterogeneous land use, local geography, and local convection patterns, which vary throughout the urban landscape, complicate this task. To establish continuous monitoring programs, it is important to first determine the heterogeneity of urban landscapes on the ground. To understand the role these factors play in the distribution of CO 2 over an urban area, we conducted a CO 2 measurement campaign over the Metropolitan Area of Barcelona (AMB) over four urban land uses: impervious, green, forest, and agricultural. There is a clear tendency for CO 2 mixing ratios to decrease as the degree of urban vegetation increases, even in the midst of a developed boundary layer. For example, CO 2 concentrations were 429 and 427 ppm at forest and agricultural sites, respectively, while 485 ppm was reported at urban sites. A decrease in atmospheric CO 2 was observed from 458 to 428 ppm in the gradient from urban to suburban areas, in which the biosphere component increased. The biosphere component of the CO 2 signal was significant and was observed in the gradient from urban to suburban areas, which averaged a reduction from 458 to 428 ppm. Our findings show that the large spatial variability in CO 2 concentrations (ranging from 410 to 495 ppm) is best explained by anthropogenic activity. We propose increasing the spatiotemporal resolution of CO 2 monitoring in the AMB to determine these trends more precisely over longer periods of time.
... While various methods, such as optical, gas chromatographic, and mass spectrometric techniques, have proven effective in detecting environmental trace gases [13], laser spectroscopy has emerged as a promising and successful alternative. In comparison with other ozone detection instruments [27][28][29][30][31][32], the LPAS instruments demonstrated a distinctive advantage. They operate over a broader spectral region, mitigating interference effects from other absorbing species like water [20]. ...
In urban areas, there has been a recent rise in ground-level ozone. Given its toxicity to both humans and the environment, the investigation of ozone pollution demands attention and should not be overlooked. Therefore, we conducted a study on ozone concentration in three distinct locations within the city of Magurele, Romania. This investigation considered variations in both structure and location during the spring and summer seasons, specifically at a breathing level of 1.5 m above the ground. Our analysis aimed to explore the impact of different locations and meteorological variables on ozone levels. The three measurement points were strategically positioned in diverse settings: within the city, in a forest, and within an industrial area. For these measurements, we used a laser spectroscopy system to determine the system’s sensitivity and selectivity and the influence of humidity in the detection of ozone in ambient air, which is a mixture of trace gases and water vapor. During the March–August campaign, the mean values in the three measuring points were 24.45 ± 16.44 ppb, 11.96 ± 3.80 ppb, and 95.01 ± 37.11 ppb. The peak concentrations of ozone were observed during the summer season. A diurnal analysis revealed that the atmospheric ozone levels were higher in the latter part of the day compared to the earlier part. These measurements suggest that the atmospheric temperature plays a significant role in tropospheric ozone production. Additionally, meteorological variables such as wind speed and direction were found to influence the ozone concentration. Remarkably, despite substantial traffic, the ozone levels remained consistently low throughout the entire period within the forested area. This observation may suggest the remarkable ability of trees to mitigate pollution levels.
... The project mentioned above on low-cost sensor dense networks has shown the feasibility of this method in the field of carbon monitoring to domestic researchers. Together with more foreign cases (Jiao et al. 2016;Lee et al. 2017;Gryech et al. 2020;Prakash et al. 2021), these projects also give China meaningful references and valuable experience in this research in the future. In Fig. 16, the timeline of the above-mentioned networks and projects is presented. ...
The development and renewal of gas sensor technology have enabled more and more low-cost gas sensors to form a carbon monitoring network to meet the requirements of the city. In the context of China’s commitment to achieving the “double carbon” target by 2060, this paper reviews the principles of four standard gas sensors and the application of several low-cost sensors in urban carbon monitoring networks, with the aim of providing a practical reference for the future deployment of carbon monitoring networks in Chinese cities. Moreover, the types, prices, and deployment of the sensors used in each project are summarized. Based on this review, non-dispersive infrared sensors have the best performance among the sensors and are commonly used in many cities. Lots of urban climate networks in cities were summarized by many reviews in the literature, but only a few sensors were studied, and they did not consider carbon dioxide (CO2) sensors. This review focuses on the dense CO2 urban monitoring network, and some case studies are also discussed, such as Seoul and San Francisco. To address the issue of how to better ensure the balance between cost and accuracy in the deployment of sensor networks, this paper proposes a method of simultaneously deploying medium-precision and high-precision fixed sensors and mobile sensors to form an urban carbon monitoring network. Finally, the prospects and recommendations, such as different ways to mitigate CO2 and develop an entire carbon monitoring system for future urban carbon monitoring in China, are also presented.
Graphical abstract
... [44][45][46] Only Lee et al. have derived CO 2 emissions at ne spatial resolution based on eld measurements. 47 In a pioneering work they applied an aerodynamic resistance method to calculate emissions from mixing ratios of CO 2 measured at street level in conjunction with mixing ratios and uxes collected from a tall EC ux tower located within the study area. They used ve mobile units to simultaneously measure CO 2 mixing ratios across ve neighborhoods and one urban park in Vancouver, Canada, and derived hourly emissions in 100 × 100 m gridcells. ...
... For this study we instrumented a bicycle to collect CO 2 mixing ratios and humidity data along streets and alleys in a residential neighborhood of Singapore where an EC ux tower was already installed, to calculate and map uxes of CO 2 and H 2 O at high spatial resolution. Similar to Lee et al., we applied the aerodynamic resistance method for Q H transfer as a proxy to derive uxes of CO 2 and H 2 O. 47 The latter is directly associated with the energy channeled into Q E . Because of the heterogenous urban landscape of Singapore characterized by districts with distinct land covers and building morphologies (i.e., Local Climate Zones, LCZ), and thus varying aerodynamic resistances, we limited the study to the neighborhood within the footprint of the ux tower. ...
... Midday r H values agree with those reported in the literature for other urban areas, but values observed in the morning and evening rush hours were higher. 47,53 Values obtained during these latter periods may be somewhat biased due to uncertainties in Q H caused by a less vigorous vertical mixing and because the assumptions necessary to apply the Monin-Obukhov similarity theory begin to break down. 13 The empirical relation used to calculate T 0 depends on the representativeness of 3 across the entire urban surface and on the radiometer view bias. ...
Based on Monin-Obukhov similarity theory and challenging Reynolds analogy, the aerodynamic resistance approach to estimate the transfer of sensible heat (QH) can be used as a proxy to investigate the...
... Time response is of particular importance in mobile sampling since a slow instrument response can distort (delay and broaden) geolocated concentration readings. Two recent studies highlighted cases where instrument response time impacted the spatial profiles [14][15][16] recorded in mobile air quality studies. A response time of <1 s is generally considered reasonable for mobile sampling as this translates to relatively small distances, e.g., to <25 m for a vehicle speed of 50 miles per hour. ...
We present a novel sensing approach for ambient ozone detection based on deep-ultraviolet (DUV) cavity-enhanced absorption spectroscopy (CEAS) using a laser driven light source (LDLS). The LDLS has broadband spectral output which, with filtering, provides illumination between ~230–280 nm. The lamp light is coupled to an optical cavity formed from a pair of high-reflectivity (R~0.99) mirrors to yield an effective path length of ~58 m. The CEAS signal is detected with a UV spectrometer at the cavity output and spectra are fitted to yield the ozone concentration. We find a good sensor accuracy of <~2% error and sensor precision of ~0.3 ppb (for measurement times of ~5 s). The small-volume (<~0.1 L) optical cavity is amenable to a fast response with a sensor (10–90%) response time of ~0.5 s. Demonstrative sampling of outdoor air is also shown with favorable agreement against a reference analyzer. The DUV-CEAS sensor compares favorably against other ozone detection instruments and may be particularly useful for ground-level sampling including that from mobile platforms. The sensor development work presented here can also inform of the possibilities of DUV-CEAS with LDLSs for the detection of other ambient species including volatile organic compounds.
... Bergeron and Strachan found a clear decrease in CO 2 fluxes from urban to suburban and agricultural areas in Montreal and concluded that the lower emissions were due to vehicular traffic contributions decreasing from 11.5 µmol m − 2 s − 1 in urban areas to 4.8 µmol m − 2 s − 1 in suburban areas (Bergeron and Strachan, 2011). Lee et al. (2017) found, using eddy covariance, that downtown areas emitted 3-5 times more CO 2 than did peripheral areas and that mixing ratios increased by 24-39 ppm from green suburban areas to downtown areas. Our study revealed an average decrease of 35 ppm in the CO 2 mixing ratio as we approached suburban areas compared to downtown areas, which was linked to this vehicular reduction occurring from urban to suburban areas. ...
... It is also noted that the Geographic Information System (GIS) is used for many types of urban and environmental spatial analysis [75]. It was used to map carbon emissions [76] and along with spatial regression, a spatial model was developed to promote walkability [77]. In this regard, the ArcGIS ModelBuilder constructs and executes simple workflows and designed queries that combine a set of geoprocessing tools that feed both output and input data. ...
This study adopts two levels of comparative urban analysis to investigate the current role played by Sabil buildings as nuclei for sustainable urban rehabilitation in Al-Muiz Street, Fatimid Cairo, Egypt. The study is tackled from an urban touristic approach to promote linear and diffused mobility. Hence, Linear Urban Mobility Analysis divided the linear spine into nine sectors based on Sabil locations. These varied in densities, activities, services, social behaviour and opportunities. They were compared based on a matrix including quantitative and qualitative parameters reflecting the existing urban conditions, and were added to an ArcGIS ModelBuilder to develop a spatial assessment model. Then, for a Diffused Urban Mobility Analysis, three proposed itineraries were compared using validated software programs to scrutinise their urban and environmental qualities. The results present a pilot study for promoting sustainable urban mobility in historic cities based on Sabil buildings contextual settings.
... The research plan. smart sensors to feed data into real-time monitoring devices as part of the building database management system [67][68][69]. ...
This study scrutinized indoor air quality (IAQ) and symptoms of Sick Building Syndrome (SBS) for a sustainable building renovation (SBR). A systemic review of existing literature was performed, including identification, screening, and scoping phases. This was followed by a keyword-based scientometric analysis. By further refining keywords, this tri-dimensional relationship was highlighted through cross-disciplinary knowledge interactions using a content analysis method. A network analysis map helped identify critical criteria and sub-criteria, later categorized into four clusters of governing data variables. A survey-based Relative Importance Weight (RIW) benchmark was performed for each variable, exhibiting its contribution towards attaining an efficient IAQ-SBR process. The Structural Equation Modelling (SEM) was used to develop a Decision Support System (DSS). This set the system's structure incorporating four hierarchical levels of assessment for achieving an IAQ-SBR. A case study building was followed to test the proposed model in a real context. In sum, this study succeeded in (1) expanding the definition and evaluation of SBR to account for IAQ, (2) developing a DSS for assessing the sustainability of the renovation process, prioritizing actions, as well as tracking and benchmarking the effect of renovation activities on IAQ, (3) creating a comprehensive comparative and absolute assessment using variables' RIWs and loading factors. The presented approach portrayed a novel academic and industry outreach contribution that put IAQ at the heart of building renovation practices. It also showed the necessity of adopting an integrated thinking approach to account for interrelated variables for an efficient IAQ-SBR.
... Carbon absorbed from the atmosphere is processed in several nutritional steps in the forests, and a large portion of the carbon is returned to the atmosphere. The quantitative analysis of CO 2 is therefore fundamental in the understanding of the material cycle of ecosystems (Lee et al., 2017). The soil CO 2 efflux comes with the processes of root respiration, heterotrophic respiration through the decomposition of soil organic matters by microorganisms, and efflux of CO 2 from the animals (Crowther et al., 2016). ...
