Concerned about air quality in Erandio, the Auzokoa People ' s Association and Herri Bideak Kate Barik initiated a collaborative project to end the pollution problem. First, they needed data to argue their claims. Thus, they decided to participate in the Aire Zaintzaileak project and, among other activities, thanks to 294 neighbors of Erandio, they distributed hammam plants throughout the municipality with the objective of analyzing air quality.

In this study, from October to December 2020, volunteers kept hammerhead plants and collected leaves for further research in a laboratory. But why the hammer leaves? The Sentinel Air initiative, launched by the Ivercivis Foundation, uses hammer plants to detect and measure heavy metals found in the air, which stick on the hairs of the leaves.

For this study, the magnetic properties (SIRM) of the metal contamination stored in the hammer leaves have been used as indicators of air pollution. In fact, the magnetic properties of hammer leaves capture fine particles of small and ultrafine matter (PM10, PM2.5 and PM0.1), reflecting the concentration of particles in the air.

In this simple but practical way, it has been possible to measure air pollution in 28 cities in the Spanish state. In Erandio, thanks to the work of these two associations, 294 plants were distributed throughout the municipality, of which 232 have been collected and 215 have been useful for the study. "It has been an impressive job for us and, in the end, not all the leaves were worth it, because many of them were corrupted or were too small, but we got the sample for research as a cow," the spokesmen of the associations say.

According to the results of the Dabordu investigation, Erandio has been left in the first place, doubling the Barcelona average, and doubling the Madrid average by four. "We were surprised, the results are much worse than we thought," they regretted. In the neighborhoods of Altzaga and Astrabudua, a high degree of contamination was not expected either, but not only that, high levels of contamination have also been detected in rural areas, "something that has not happened anywhere else in the state".

In-depth analysis and controls

Thanks to these results, the Association Vecinal Auzokoa and Herri Bideak Kate Barik have a fixed basis to motivate their demands and, among other things, have asked the City of Erandio to carry out a comprehensive analysis of air pollution, installing meters and chromatographs at different points in the municipality.

On the other hand, the results have also been transferred to the local health center, political parties, the different departments of the Basque Government and the Ararteko for each to take action in their field of work, among which they have asked the different agents to conduct deeper research and have called for greater control in compliance with integrated environmental authorizations.