Using remote sensing and Earth system models to improve air quality and public health in megacities

Using remote sensing and Earth system models to improve air quality and public health in megacities. 

Background: Ambient air pollution in cities is of growing concern as urbanization and economic development continue, yet many cities lack information on exposure levels and local health impacts, both of which are needed to make evidence-based mitigation decisions. Through the Climate and Clean Air Coalition (CCAC), the U.S. and intergovernmental organizations such as the World Health Organization (WHO) aim to develop capacity for air quality management in cities, but have identified the lack of health impact assessment tools as a key challenge. While decision-support tools to assess air quality and health benefits of mitigation options exist at the national scale, such tools are not widely available at the city scale, where clean air interventions are often targeted. Remote sensing and Earth system models, widely used for assessing air pollution health impacts on global scales and evaluating long-term trends, could be of particular value for targeted assessment of air pollution exposures and  but spatially and temporally sparse ground-based monitoring.

Objectives: Our overall objective is to meet the needs of the U.S. and international organizations to quantitatively assess air pollution health impacts and mitigation benefits in cities, leveraging the global coverage and fine spatial resolution from remote sensing, combined with Earth systems models and in situ measurements. Specifically, we aim to:

1) Improve and verify estimates of urban fine particulate matter (PM2.5), ozone (O3), and nitrogen dioxide (NO2) concentrations and NOx and SOx emissions using NASA satellite data from MODIS, MISR, CALIPSO, OMI (as well as TROPOMI, eventually), and the GEOS-Chem model for five pilot cities (Accra, Dhaka, Paris, Santiago, and Washington, DC) that are pursuing improved air quality management and serve as models for other cities;

2) Estimate 15-year trends in PM2.5, O3, and NO2 exposures and associated mortality and morbidity burdens at 0.01x0.01 degree resolution;

3) Expand the national-scale tool used by the CCAC to estimate health benefits of mitigation policies (Long-Range Energy Alternatives Planning system with Integrated Benefits Calculator, LEAP-IBC) to the urban scale in three pilot cities (Accra, Dhaka, and Santiago);

4) In partnership with the U.S. EPA, CCAC, and local government officials, apply the new Urban LEAP-IBC tool to assess health benefits of air quality policy options in these three pilot cities.

Decision-making: We will develop new capabilities for air quality decision-making in pilot cities through an innovative urban-scale health impact assessment tool, Urban LEAP-IBC. This tool will enable local governments to conduct cost-benefit analysis of city-level mitigation options, and will be used to evaluate policies currently being considered in pilot cities (e.g. public transportation design in. Accra, improved brick kilns in Dhaka, Santiago􀁊s Metropolitan Regional Action Plan). It will also enhance the ability of the U.S. EPA (under its Africa Megacity Partnership underway in Accra and Megacities Partnership for the Santiago Metropolitan Region), CCAC, WHO, World Bank, and others to promote air quality management tools in cities world-wide.

Impact: The project will provide new capability to evaluate health benefits of urban air quality management options, enhance integration of public health into urban air quality decision-making, and enable more efficient targeting of energy and emission policies to achieve health benefits. It will also facilitate broader and long-term adoption of satellite-based methods for air quality and public health management in tools used by the CCAC, WHO, UN, and city governments beyond the extent of the project. In the longer run, our exposure estimates, linked to local health data, can support local epidemiologic analysis, further building the evidence base needed for local air quality policy development.