SmogRank / Aosta / Milan

Aosta vs Milan: PM2.5 compared

Over the last year, Milan's air was 49% more polluted than Aosta's: PM2.5 averaged 13.6 µg/m³ against 9.1, on the 139 days both cities were measured. Milan had the dirtier air on 114 of those days, Aosta on 25. Milan was over the WHO's daily guideline of 15 µg/m³ on 38 of them, Aosta on 20.

Right now

Aosta#178on the 24-hour board of 1,616, at 66 US AQI (16.9 µg/m³)
Milan–not on the 24-hour board right now

The last year, day by day

Aosta
Milan
Each city's daily mean from 6 Oct 2025 to 5 Oct 2026, one stripe a day, coloured by band. A blank stripe is a day without a daily mean.

Month by month

15Nov 2025DecJan 2026FebMarAosta, Apr: 8.1 µg/m³Milan, Apr: 13.2 µg/m³AprAosta, May: 6.1 µg/m³Milan, May: 9.3 µg/m³MayAosta, Jun: 8.5 µg/m³Milan, Jun: 10.0 µg/m³JunAosta, Jul: 8.8 µg/m³Milan, Jul: 11.5 µg/m³JulAosta, Aug: 8.9 µg/m³Milan, Aug: 11.9 µg/m³AugAosta, Sep: 10.9 µg/m³Milan, Sep: 13.8 µg/m³SepOct
Monthly means in µg/m³ over the days both cities were measured. Solid: Aosta. Faded: Milan. A month shows once both share 10 such days. Dashed line: the WHO daily guideline.

Year by year

YearAostaMilanDays both measuredDays Aosta was worse
2026 so far495712825
2025395717117
2024436316023

Means in US AQI over the days both cities were measured that year; a year shows once they share 30 such days.

Each city's worst days

Aosta

Milan

Daily means in US AQI, over the days both cities were measured in the last year. Each date opens that day's world board.

Compare either city with another

Aosta

Side by side with Passy, Gujranwala.

Milan

Side by side with Monza, Vinovo, Gujranwala.

Use this page

SmogRank, PM2.5 daily means compared, Aosta and Milan, 8 Oct 2025 – 4 Oct 2026, smogrank.com/compare/it-aosta/it-milan (accessed 6 Oct 2026).

You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.

The same rules as every SmogRank figure: reference monitors first, and a day counts with 18 measured hours. How we measure.

Updated 2026-10-06 21:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index.