Helsinki vs Lahti AQI Comparison

Side-by-side OpenAQ-derived air quality comparison for Helsinki and Lahti. Values use mapped daily PM2.5 and PM10 observations normalized to US EPA AQI.

Lower average AQI: Lahti (7-pt gap)PM2.5: Helsinki 5.8 ug/m3 · Lahti 4.5 ug/m3

Source: OpenAQ local exports mapped to AQI Now cities; city summaries cover 2024-01-01–2024-12-31 and 2024-01-01–2024-12-31.

Compare two cities

City A

City B

Helsinki vs Lahti

Helsinki

Uusimaa, Finland

PM2.5: 5.8 ug/m3
PM10: 14.3 ug/m3
Worst month: May
Trend: n/a

EPA category: Good

Lahti

Päijät-Häme, Finland

PM2.5: 4.5 ug/m3
PM10: 11.7 ug/m3
Worst month: April
Trend: n/a

EPA category: Good

Lower average AQI in this selected period: Lahti. Values are historical OpenAQ-derived city summaries, not live readings.

Yearly EPA AQI trend

Seasonal EPA AQI heatmap

JanFebMarAprMayJunJulAugSepOctNovDec

Helsinki

Lahti

What this comparison measures

Average EPA AQI — city-level daily AQI values averaged across the OpenAQ coverage window.
PM2.5 and PM10 — mapped monitor concentrations aggregated to daily city averages.
Seasonality — worst and cleanest months from the monthly city rollups.
Trend — difference between the earliest and latest yearly AQI average in this build.