Dataset - CKAN MobiDataLab

Air quality - Average concentration - NO2 - PM2.5 - PM10 - O3 from 2004 to 2014

Data set on annual average concentrations of pollutants (rolling average of the last 3 years) for the nitrogen dioxide NO2, PM10 particles, fine particles PM2.5 and Ozone O3...
Air quality – Number of days exceeding thresholds - NO2 - PM10 – O3

Dataset determining the number of days for each pollutant, Nitrogen dioxide (NO2) – Particles ( PM10) – Ozone (O3) where the information and alert thresholds have been exceeded....
Air quality - Average concentration - NO2 - PM2.5 - PM10 - O3 from 2004 to 2014

Dataset of annual average pollutant concentrations (rolling average of the last 3 years) for the nitrogen dioxide NO2, PM10 particles, PM2.5 fine particles and Ozone O3 from...
- https://www.iana.org/assignments/media-types/application/json
- https://www.iana.org/assignments/media-types/text/csv
Air quality – Number of days when thresholds are exceeded - NO2 - PM10 – O3

Dataset determining the number of days for each pollutant, Nitrogen Dioxide (NO2) – Particles ( PM10) – Ozone (O3) where information and alert thresholds have been exceeded....
- https://www.iana.org/assignments/media-types/application/json
- https://www.iana.org/assignments/media-types/text/csv
Air quality - Average concentration - NO2 - PM2.5 - PM10 - O3 from 2015

Dataset of annual average pollutant concentrations (rolling average of the last 3 years) for the nitrogen dioxide NO2, PM10 particles, PM2.5 fine particles and Ozone O3 from...
- https://www.iana.org/assignments/media-types/application/json
- https://www.iana.org/assignments/media-types/text/csv

You can also access this registry using the API (see API Docs).