Key features

• Live map of Greece: 90 areas shown on a Leaflet map, each marker coloured by its current air quality, with a popup for the AQI and the weather.
• Overview at a glance: number of areas, average AQI for the whole country, and the areas with the best and the worst air right now.
• Weather & AQI per area: temperature, feels-like, humidity, wind and pressure, plus an AQI gauge with a short explanation of what the level means.
• Pollutants: NO₂, O₃, SO₂, PM2.5, PM10 and CO for the selected area, shown as cards and as a bar chart built with Chart.js.
• 5-day forecast: daily temperatures together with the expected air quality for each day.
• Activity assessment: pick a low, moderate or high sensitivity and get a recommendation for outdoor activities, with the dominant pollutant highlighted.
• Always up to date: data refreshes automatically every 15 minutes and is cached in the browser, with a manual refresh button.

How the AQI is calculated

The app follows the European Air Quality Index. For each pollutant it finds the band the measured concentration falls into (Good, Fair, Moderate, Poor, Very Poor, Extremely Poor) and converts it into a sub-index with linear interpolation. The highest sub-index becomes the AQI of the area, and that pollutant is reported as the dominant one. The same calculation colours the map, ranks the best and worst areas and drives the recommendations.

From version 1 to version 2

This is the second version of the project. The first version focused on 10 areas of Thessaloniki and worked with historical air quality and weather data stored in JSON files: you chose a date on a calendar and your sensitivity, and the map showed where it was best to go outside. Version 2 expands the idea to the whole of Greece and replaces the stored data with live measurements and forecasts.