Speakers
Description
This study explores the exposure to vehicular emissions in relation to social vulnerability. It takes a disaggregate, activity-based modelling approach to estimate tailpipe emissions at the road network level. The vulnerability index was derived based on socioeconomic information from census tabulations. It is necessary to investigate the exposure of harmful emissions on vulnerable populations as they are often susceptible to chronic health impacts, creating environmental justice issues (Molchan et al., 2024). Emissions are not equally dispersed and may impact people who may not be emitting them. Therefore, this study estimates tailpipe emissions and a vulnerability index to develop an emissions vulnerability assessment for Halifax Regional Municipality (HRM) in Nova Scotia, Canada.
The activity-based travel model was developed utilizing the 2022 Halifax Travel Activity Survey. The model consists of four segments: 1) Population synthesis, 2) Activity generation and scheduling, 3) Vehicle allocation and mobility assignment, and 4) Traffic and emission estimation. Greenhouse gas emission (GHG) is used as a proxy to understand exposure to vehicular emissions. The vulnerability index begins with a principal component analysis (PCA) to identify relative importance of socioeconomic attributes of individuals at the zonal level. In total, twelve attributes were considered in the development of a social vulnerability index (SoVI), focusing on four thematic areas: 1) Diversity and housing suitability, 2) Socioeconomic and mobility patterns, 3) Demography, and 4) Economic challenges. The resulting SoVI of different zones in HRM were overlayed with the vehicular emissions by utilising GIS analysis. It assesses emission vulnerabilities by classifying both vulnerability and emissions based on percentiles.
This paper identifies vulnerable areas to tailpipe emissions. The result of the SoVI shows that many of the lower income zones experience higher levels of emissions, particularly in the downtown areas. For instance, a Northern portion of Halifax exhibited the high score of 2.1. Interestingly, Halifax South end, which is adjacent to Halifax’s North end, also showed a high score of 2.0, despite being considered a high-income area. In general, tailpipe emissions are highest in urban areas, followed by suburban and rural zones. Similarly, the variability of vulnerability index is highest in urban areas, while decreasing in suburban and rural zones. This correlation underscores the greater significance of vulnerability to tailpipe emissions in the urban zones within the cities of Halifax and Dartmouth.
This provides valuable insights to identify vulnerable populations that are exposed to tailpipe emissions. This study offers important policy guidelines including reduction of vehicular activity in the downtown core by diversifying public transportation. The study also reveals environmental justice issues in Canadian cities that require further climate action to reduce the impact of over-reliance on private vehicles. Such transport policies will help Canadian governments and organizations to reduce their tailpipe emission levels for vulnerable populations and aim to achieve net-zero by 2050.
References
Molchan, C., Zhang, W., Fitzpatrick, A. and Mutic, A. (2024). Clustering by chemicals: A novel examination of chemical pollutants and social vulnerability in children and adolescents. Environmental Research, 250, pp.1–9. doi:https://doi.org/10.1016/j.envres.2024.118456.
| Keywords | activity-based model; tailpipe emissions; social vulnerability index; transportation policy |
|---|---|
| Best Congress Paper Award | Yes |
