Flexible Workflow for Determining Critical Hazard and Exposure Scenarios for Assessing SLODs Risk in Urban Built Environments

Abstract

Urban Built Environments (UBE) are increasingly prone to SLow-Onset Disasters (SLODs) such as air pollution and heatwaves. The effectiveness of sustainable risk-mitigation solutions for the exposed individuals’ health should be defined by considering the effective scenarios in which emergency conditions can appear. Combining environmental (including climatic) conditions and exposed users’ presence and behaviors is a paramount task to support decision-makers in risk assessment. A clear definition of input scenarios and related critical conditions to be analyzed is needed, especially while applying simulation-based approaches. This work provides a methodology to fill this gap, based on hazard and exposure peaks identification. Quick and remote data-collection is adopted to speed up the process and promote the method application by low-trained specialists. Results firstly trace critical conditions by overlapping air pollution and heatwaves occurrence in the UBE. Exposure peaks (identified by remote analyses on the intended use of UBEs) are then merged to retrieve critical conditions due to the presence of the individuals over time and UBE spaces. The application to a significant case study (UBE in Milan, Italy) demonstrates the approach capabilities to identify key input scenarios for future human behavior simulation activities from a user-centered approach.

Pedestrian Single and Multi-Risk Assessment to SLODs in Urban Built Environment: A Mesoscale Approach

“…Given the overall context regarding impacts on pedestrians and their tasks in the urban BE, the main SLODs hazards identified in this study are increasing temperature and air pollution. According to previous approaches [11,26], data collection of the main hazard conditions arising from air pollution and increasing temperature in the BE is made using indexes such as the universal thermal climate index (UTCI) [27] and the air quality index (AQI) [28]. These can be used in a simplified manner, which requires rather commonly surveyed parameters to estimate the pedestrian's sensation of their surroundings.…”

“…Differently, exposure is focused on human presence (e.g., the total number of people, overcrowding probability) [29], which essentially changes over time and space depending on urban BE use in indoor and outdoor areas [11,29,30].…”

“…Previous studies [11,48] have represented the daily variations of the risk conditions, but less has been done in the management of risk data and overall conditions for ASs and LSs composing the real-world roads network. In this sense, the development of quick methods able to dynamically manage and represent (i.e., through maps) is one of the recommended steps to support stakeholders and decision makers to assess "hotspots" in the urban BE due to SLODs risks.…”

“…High UHI values compromise citizens' everyday commuting, open-air activities, and well-being in general [5]. Moreover, air pollution and increasing temperatures have been recognized by numerous studies as the most relevant SLODs because of the great impact they have on people's health and on BEs in the medium and long term [5,11,12]. In addition, they have a considerable correlation with other SLODs (e.g., glacial retreat, ocean acidification) [13].…”

Built Environment Typologies Prone to Risk: A Cluster Analysis of Open Spaces in Italian Cities

“…Considering SUODs, the presence of special buildings attracting visitors (including tourists) could represent special targets for terrorist acts, increasing the exposure for people hosted in the BE [22]. Concerning SLODs, special buildings can increase the exposure, in terms of numbers and types of people with possible health fragilities and risky conditions of overcrowding [51].…”