Statistics on pollution with ultrafine particles (the most common of the dangerous types of pollution (PM10, PM2.5)) in the form of an Excel table available for download and analysis:

https://www.who.int/airpollution/data/aap_air_quality_database_2018_v14.xlsx?ua=1

Database actual on 27.05.2023 (still old years): https://cdn.who.int/media/docs/default-source/air-pollution-documents/air-quality-and-health/who_aap_2021_v9_11august2022.xlsx?sfvrsn=9035996c_3