# Air Quality Outlook

> Free air quality explorer: pick a city or one of about 14,000 OpenAQ monitoring stations and see the U.S. AQI day by day,
> PM2.5, PM10, ozone, NO2, SO2 and CO against WHO guidelines, the cleanest hours of the day and a statistical 3-day outlook.

URL: https://air-quality-outlook.skillsafe.ai/

## What it does

- Place picker: search 165 major cities or about 14,000 stations by name; "near me"; other stations within 25 km; seven
  bundled examples (Delhi, Lahore, London, Los Angeles, Mexico City, Paris, Seoul) that load without an account. Span: the
  last 30, 60 or 90 days.
- Latest reading: EPA NowCast AQI for PM2.5 and PM10 with its category and health advice, plus the latest value and
  sub-index of each pollutant.
- Daily AQI chart coloured by category (U.S. EPA, 2024 PM2.5 breakpoints), the main pollutant per day, worst and cleanest day.
- Pollutant chart: hourly values, the daily AQI metric (24-hour mean, highest 8-hour mean or highest hour), the WHO 2021
  guideline level and the AQI-100 level.
- Days by AQI category, mean and days above the WHO guideline per pollutant, and a time-of-day profile with the cleanest and
  dirtiest 3-hour windows.
- 3-day outlook: clearly labelled a statistical trend, not an official forecast. Each pollutant's daily value relaxes from
  its latest level toward its 14-day mean (log scale, persistence fitted per station, weekday pattern with 6+ weeks), with an
  80% range and the chance of AQI over 100. A rolling-origin backtest reports its error against repeating the last day.
- Your own CSV (long: time, parameter, value, units; or wide: a time column plus pm25, pm10, o3, no2, so2, co columns),
  read in the browser and never uploaded.
- Exports: daily AQI CSV, hourly CSV, every chart as SVG, a shareable link.

## Data

- OpenAQ open-data archive (hourly measurements from government, research and community monitors; each original provider is
  credited by OpenAQ; licences vary by provider). Published about two to four days behind real time.
- Live stations are fetched through the app's server function and need a free SkillSafe sign-in. No credits are used and
  nothing is stored.

## API

- https://air-quality-outlook.skillsafe.ai/api.html (GET /api/days?location=ID&start=YYYY-MM-DD&end=YYYY-MM-DD, CSV)