Examining the social distributions in neighbourhood black carbon and ultrafine particles in Montreal and Toronto, Canada

IF 9.7 1区环境科学与生态学 Q1 ENVIRONMENTAL SCIENCES Environment International Pub Date : 2025-03-18 DOI:10.1016/j.envint.2025.109395

Emmanuelle Batisse , Marshall Lloyd , Alicia Cavanaugh , Arman Ganji , Junshi Xu , Marianne Hatzopoulou , Jill Baumgartner , Scott Weichenthal

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Abstract

Background

Socioeconomic inequities in outdoor ultrafine particles (UFP) and black carbon (BC) are understudied in Canada, where metropoles like Montreal and Toronto feature distinct sociodemographic diversity and urban characteristics compared to U.S. cities.

Methods

We collected vulnerability indicators, including social, economic, household composition, and immigration status, at the dissemination area level for Montreal and Toronto using data from the 2006 and 2021 Canadian Census of Population. Areas were classified as disadvantaged, intermediate, or advantaged following K-means clustering analysis. We aggregated and calculated population-weighted average concentrations of BC and UFP, and UFP size at the dissemination area and cluster levels using high-resolution exposure surfaces, derived from year-long mobile monitoring campaigns conducted in each city during 2020–2021. Final exposure surfaces were generated by integrating predictions from land-use regression models and deep convolutional neural network models.

Findings

We observed high within-city variations in aggregated air pollutant levels, with higher outdoor BC and UFP concentrations and smaller UFP sizes in areas near local sources such as major roads, railways, airports, and densely populated regions. Advantaged areas experienced the lowest median UFP concentrations in both Montreal (10,707 pt/cm³) and Toronto (10,988 pt/cm³), as well as the lowest BC concentrations (650 ng/m³) in Montreal. The highest median UFP concentrations were observed in intermediate areas in Montreal (15,709 pt/cm³) and disadvantaged areas in Toronto (12,228 pt/cm³). Conversely, the highest BC concentrations were observed in disadvantaged and intermediate areas in Montreal (805–811 ng/m³), and disadvantaged and advantaged areas in Toronto (1,228–1,252 ng/m³). Notably, high priority areas for the double burden of vulnerability and high BC and UFP concentrations were located near air pollutants local emission sources.

Interpretation

Our findings highlight the importance of prioritizing exposure mitigation for populations residing near local sources and to understand contextual factors influencing inequities across cities and pollutants.

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加拿大蒙特利尔和多伦多社区黑碳和超细颗粒的社会分布研究

加拿大对室外超细颗粒（UFP）和黑碳（BC）的社会经济不平等现象研究不足，与美国城市相比，蒙特利尔和多伦多等大都市具有明显的社会人口多样性和城市特征。方法利用2006年和2021年加拿大人口普查数据，收集蒙特利尔和多伦多传播区层面的脆弱性指标，包括社会、经济、家庭构成和移民身份。根据k均值聚类分析，将地区分为不利、中等或有利。我们利用高分辨率暴露面汇总并计算了传播区和群集水平的BC、UFP和UFP的人口加权平均浓度，这些数据来自2020-2021年期间在每个城市开展的为期一年的移动监测活动。最终暴露面由土地利用回归模型和深度卷积神经网络模型综合预测生成。研究结果：我们观察到城市内空气污染物总量水平的差异很大，室外BC和UFP浓度较高，而靠近当地污染源（如主要道路、铁路、机场和人口稠密地区）的UFP规模较小。蒙特利尔（10,707pt/cm3）和多伦多（10,988pt/cm3）的优越地区UFP浓度中值最低，蒙特利尔的BC浓度最低（650 ng/m3）。最高中位UFP浓度出现在蒙特利尔的中间区域（15,709pt/cm3）和多伦多的弱势区域（12,228pt/cm3）。相反，在蒙特利尔的不利和中间地区（805-811 ng/m3）和多伦多的不利和有利地区（1,228-1,252 ng/m3）观察到最高的BC浓度。值得注意的是，高BC和UFP浓度和脆弱性双重负担的高优先区域位于空气污染物当地排放源附近。我们的研究结果强调了优先考虑居住在当地污染源附近的人群的暴露缓解的重要性，并了解影响城市和污染物不平等的背景因素。

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来源期刊

Environment International 环境科学-环境科学

CiteScore

21.90

自引率

3.40%

发文量

734

审稿时长

2.8 months

期刊介绍： Environmental Health publishes manuscripts focusing on critical aspects of environmental and occupational medicine, including studies in toxicology and epidemiology, to illuminate the human health implications of exposure to environmental hazards. The journal adopts an open-access model and practices open peer review. It caters to scientists and practitioners across all environmental science domains, directly or indirectly impacting human health and well-being. With a commitment to enhancing the prevention of environmentally-related health risks, Environmental Health serves as a public health journal for the community and scientists engaged in matters of public health significance concerning the environment.