Insights and Policy Implications from a Harmonized Earth Observation
Approach to Urban Air Quality
Abstract
Earth observation (EO) offers a promising and necessary approach to
addressing environmental issues and sustainable development from the
city to the global scale. The full potential is currently untapped, as
global harmonization is necessary for comparability and scalability, as
well as streamlining EO integration into informed and efficient
decision-making. Focusing specifically on city needs, local and national
authorities regulate urban air pollution, while the UN SDG 11 indicator
11.6.2 explicitly targets air pollution accounting for population in
“cities” and aggregating to the national level. EO brings forth novel
monitoring methods to achieve this alongside more traditional ones.
However, how a city is spatially defined is an ongoing area of research
and policy activity where the definitions differ, which can greatly
impact the estimation of exposure to air pollution. To address the
varying definitions and move toward a harmonized global approach, the
H2020 SMURBS/ERA-PLANET project has created a workflow and tool that
adopts two well established definitions of cities to assess
population-weighted particulate matter (PM) pollution for approximately
800 European cities. The workflow utilizes the Copernicus Atmospheric
Monitoring Service (CAMS – regional ensemble reanalysis) data for
PM2.5, an open and free European-wide source of air pollution data,
overlaid with two European Commission acknowledged city boundary
definitions: the Functional Urban Area and the JRC’s Degree of
Urbanisation Urban Centre. These two approaches yield different results
allowing stakeholders to comprehend the city boundary sensitivity.
Statistical analysis on the results will highlight cases throughout
Europe to showcase how important and potentially policy relevant the
differences can be based on a city’s definition, especially if there is
a divergence when aggregated to the national level. The GKH will
disseminate the knowledge-based workflow and give prominence to the its
global relevance, providing a much needed resource for developing
countries and giving decision-makers an EO-based consistent tool to help
meet societal challenges that are intertwined with urban growth.