Semi-parametric methods for long-term trend detection in air quality: The North-Eastern Italian Alps case.

Long-term air pollution trends in the North-East Italian Alps show a 50% decline in NO and 30% in PM, while O3 increased by about 20%, based on data from 2009 to 2023.

• Why it matters: Understanding these trends is crucial for evaluating the effectiveness of pollution control measures and addressing regional air quality challenges in complex terrains like the Alps.
• What they did: The study used 40 monitoring stations and applied Generalized Additive Models with Tobit likelihood and Box-Cox transformation to analyze daily measurements of NO, NO2, O3, PM10, and PM2.5, accounting for seasonal and weather effects.
• The result: Results reveal high variability driven mainly by autoregressive persistence and seasonality, with short-term factors dominating, indicating that local pollution changes are heterogeneous and influenced more by immediate conditions than long-term trends.