Finland City AQI Comparison
Rank cities side by side using OpenAQ PM2.5 and PM10 history normalized to US EPA AQI. This pilot covers 22 eligible cities with OpenAQ-derived daily AQI history.
Compare two cities
vs
Featured comparisons
Helsinki vs Vaasa→
Highest vs cleanest city
AQI gap 21350 / 329 days
Helsinki vs Pori→
Highest-AQI pair
AQI gap 0350 / 308 days
Helsinki vs Lahti→
High vs mid-range city
AQI gap 7350 / 345 days
Pori vs Vaasa→
Second-highest vs cleanest city
AQI gap 21308 / 329 days
Kauniainen vs Hamina→
High vs low-AQI city
AQI gap 10331 / 221 days
Pori vs Hamina→
High vs low-AQI city
AQI gap 12308 / 221 days
Pori vs Kauniainen→
Similar high-AQI cities
AQI gap 2308 / 331 days
Kauniainen vs Klaukkala→
High vs low-AQI city
AQI gap 8331 / 331 days
Kauniainen vs Vantaa→
Similar high-AQI cities
AQI gap 2331 / 346 days
Vantaa vs Tampere→
High vs low-AQI city
AQI gap 5346 / 342 days
Vantaa vs Lappeenranta→
Similar high-AQI cities
AQI gap 1346 / 331 days
Lappeenranta vs Oulu→
High vs low-AQI city
AQI gap 3331 / 346 days
Methodology
The extractor maps OpenAQ monitoring locations to the nearest AQI Now city in the same country, aggregates PM2.5 and PM10 to daily city averages, and converts those concentrations to US EPA AQI. Country tool pages use only city summaries that satisfy the configured minimum daily coverage threshold.