PM2.5 in Portugal: When the Fine Wind Blows
The spatial distribution of PM reflects multiple environmental and social drivers.
Winds are decisive: they disperse PM2.5 far beyond industrial or urban sources,
transforming what may appear as a localised burden into a diffuse externality.
This redistribution reshapes both the geography of exposure and the sociology of
responsibility, as the costs of production are absorbed by the wider community.
Wind-mediated transport can extend over hundreds of kilometres. Winds also influence urban heat islands, odour corridors, and noise propagation, framing the lived experience of environmental externalities in dense cities. Acting simultaneously as ecological and social forces, they spread the by-products of production and consumption across unequally positioned populations. Seasonal wind rose diagrams illustrate these dynamics by showing the frequency of wind direction and speed, with spokes indicating time proportions and concentric circles cumulative frequency. Colour gradients correspond to PM2.5 concentrations, allowing simultaneous interpretation of prevailing winds and particulate matter intensities (data from January 2019 to March 2025).
Wind-mediated transport can extend over hundreds of kilometres. Winds also influence urban heat islands, odour corridors, and noise propagation, framing the lived experience of environmental externalities in dense cities. Acting simultaneously as ecological and social forces, they spread the by-products of production and consumption across unequally positioned populations. Seasonal wind rose diagrams illustrate these dynamics by showing the frequency of wind direction and speed, with spokes indicating time proportions and concentric circles cumulative frequency. Colour gradients correspond to PM2.5 concentrations, allowing simultaneous interpretation of prevailing winds and particulate matter intensities (data from January 2019 to March 2025).
Timelapses can be viewed for each month across different years, and for each municipality.
PM2.5 monthly and annual means (January 2019–March 2025) were obtained from the
Copernicus Atmosphere Monitoring Service (CAMS) Near-Real-Time reanalysis (ECMWF). Wind
fields were derived from the ERA5 reanalysis (ECMWF) via the Copernicus Climate Data Store,
which provides hourly wind components at 10 m above ground level (u, v) from assimilated satellite and
in-situ observations. Monthly and annual means were likewise computed in
Google Earth Engine and aggregated for the 308 municipalities of Portugal.