[OC] Interactive map of European Air Quality (NO2 & PM2.5) and Temperature trends using Copernicus CAMS/ERA5 data Hi everyone, I built this interactive explorer to make it easier to visualize, query, and compare historical air quality and climate data across Europe. Data Sources: Air Quality (NO2, PM2.5, PM10, O3): Copernicus Atmosphere Monitoring Service (CAMS) European reanalysis dataset at 0.1° resolution (2013-Present). Climate (Temperature, etc.): Copernicus Climate Change Service (C3S) ERA5 reanalysis dataset at 0.25° resolution. Tools Used: Frontend: Astro, Tailwind CSS, Leaflet for the map, and Chart.js for the graphs. Backend: Go API with a custom C++ query engine using io\_uring to achieve sub-20ms query latency across hundreds of gigabytes of compressed historical data. The tool lets you click anywhere on the map (or search for a city) to see annual averages against the WHO safety guidelines, as well as monthly seasonal trends.…