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Health Impact Assessments

Health Impact Assessments

Many cities in Latin America have implemented urban interventions to mitigate and adapt to climate change effects. Health Impact Assessment (HIA) offers a structured approach to anticipating the health impacts of plans, programs, or projects, with the aim of incorporating these findings to support decisionmaking.

SALURBAL-Climate is implementing two Health Impact Assessments (HIAs) to study the health effects of urban interventions in Santiago, Chile and Bogotá, Colombia. Our approach is based on the Health Impact Analysis (HIA) model promoted by the Pan American Health Organization (PAHO).

BROTAR: Urban Tree Plan

📍 Santiago, Chile

"RUCAS Clima" is led by the School of Public Health at the Faculty of Medicine at the Pontificia Universidad Católica de Chile. The study is evaluating the Regional Government's Strategic Urban Tree Plan. The Tree Plan is one component of the broader BROTAR Program developed by the Department of Environment, Biodiversity, and Climate Action of the Regional Metropolitan Government of Santiago.

RUCAS Clima employs a multi-method and observational approach to evaluate impacts of the intervention and support decisionmaking. The HIA addresses two pilot interventions of the Urban Tree Plan:

  • Tree planting along Santiago's main avenue, Alameda
  • Planting of an urban forest in Conchalí

The study will evaluate the potential for urban greening to mitigate the effects of heat on health and quality of life of the resident and floating population in these areas. The team's approach involves decision-makers, technical and academic experts, as well as community organizations, residents, and the floating population. It collects qualitative information through brief interviews with passersby in two segments of the Alameda and through interviews and a focus group with members of the Conchalí Urban Forest community. Additionally, based on the most robust scientific evidence available, the study projects the health impact of the intervention for different tree coverage scenarios, quantified as the number of prevented deaths.

Transformation of Carrera Séptima

📍 Bogotá, Colombia

The urban transformation of Carrera Séptima seeks to promote active transportation, expand green spaces, and improve public transportation, which could also translate into improved air quality. The SALURBAL team is developing a Health Impact Assessment to estimate the potential impact of the transformation on premature deaths.

This HIA is developed in six stages: (i) selection of the intervention, (ii) definition of the scope of the analysis, (iii) analysis of the expected impacts, (iv) formulation of recommendations, (v) reporting of results, and (vi) monitoring of the implementation of the recommendations provided by the HIA.

Methodology

The quantitative analysis is being developed at the census tract level and leverages tools developed by the World Health Organization:

  • AirQ+, which uses annual concentrations of air pollutants (PM2.5, O3, NO2, and eBC), population over 30 years of age, and natural cause mortality rates to quantify the health outcomes (measured in premature mortality) attributable to air pollution.
  • GreenUR, which leverages data on the Normalized Difference Vegetation Index (NDVI), population over 18 years of age, and mortality rate to quantify predicted reduction in mortality from natural causes attributable to the presence of and access to urban green spaces.
  • HEAT, which uses data on the number of people who walk or cycle, the average time spent walking or cycling, and mortality rates to quantify the economic value of the reduction in premature mortality associated with time spent walking or cycling.

Expected Results

Expected results from this HIA include:

  • Number and rate of deaths attributable to air pollution that would be avoided through urban transformation
  • Reduction in premature deaths attributable to renaturalization interventions
  • Reduction in premature deaths among adults due to walking or cycling
  • Associated economic valuation of reductions in premature deaths

Impact and Collaboration

This study highlights the importance of interdisciplinary work to assess health impacts resulting from urban interventions and leverages collaboration between researchers in health, environment, mobility, and planning sectors, among others. Findings will be shared with decision makers to support informed, evidence-based decisionmaking around this strategic project, and with technical staff from the city's public institutions to support knowledge transfer and catalyze the use of WHO tools.

Based on these results and dialogue with key stakeholders, concrete recommendations will be generated to optimize the design and implementation of the urban intervention, with the aim of maximizing its health benefits, reducing inequalities, and promoting a more equitable and healthy use of urban space in Bogotá.