Lombardy reports record ozone pollution levels in summer 2026

A report by Legambiente Lombardia reveals critical levels of ozone pollution across the Lombardy region during the summer of 2026. High temperatures and prolonged dry weather between May and September facilitated chemical reactions between pollutants such as methane and nitrogen oxides, leading to significant photochemical smog.

Many provincial capitals exceeded European regulatory limits, which permit no more than 25 days per year above 120 micrograms per cubic meter. Bergamo and Monza recorded the highest levels, with over 110 days of unhealthy air. Other cities, including Brescia, Lecco, Milan, Varese, Cremona, and Lodi, surpassed the limit for more than 90 days.

Varese showed a marked worsening of air quality, recording 96 days above the limit, a significant increase from 48 days in 2025. Additionally, Varese recorded 69 hours above the information threshold of 180 micrograms per cubic meter, the level at which authorities must alert the public to potential health risks.