Air quality readings by ‘citizen scientists’ are revealing a far worse picture than that acknowledged by officials. Data collected in Budapest by the Clean Air Action Group (CAAG) suggests that air pollution in the city is far more harmful than that recorded by official measuring stations.

While official data already demonstrates that the concentrations of certain harmful substances in Budapest’s air regularly exceed air quality limit values, CAAG’s measurements highlight a further problem ignored by officials: ultrafine particulate matter (UFPs).

With a diameter smaller than 100 nanometres, these particles are especially dangerous and particularly hard to measure.

Although Budapest’s air can contain a very large number of UFPs, their mass is so vanishingly small that official figures, which assess air pollution by measuring the mass of pollutants contained in one cubic metre, do not capture the magnitude of the problem.

CAAG has recently acquired a new device that has enabled more accurate measurements over the last four months. The new instrument can measure the number of particles with diameters between 10 and 700 nanometres in one cubic centimetre.

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