# World Weather Online, free: Air quality API

> Real-time air pollution data including PM2.5, PM10, ozone, NO₂, SO₂, and CO concentrations for health-conscious apps and environmental monitoring solutions.

World Weather Online's air quality API on its Free plan. It costs $0.00 per 1,000 places. It returns 2 of the 6 key fields we check: Particles, Gases.
We rank 94 plans by price. [OpenWeather's £370 monthly plan](https://datacircle.dev/air-quality-apis/openweather/370-monthly-professional-get-data-2-5-air-pollution/llms.txt) is the cheapest paid plan per 1,000 places: $0.00049.
[WeatherAPI.com](https://datacircle.dev/air-quality-apis/weatherapi-com/7-monthly/llms.txt), [Open-Meteo](https://datacircle.dev/air-quality-apis/open-meteo/99-monthly-api-professional-get-v1-air-quality-air-quality/llms.txt) and [Weatherbit](https://datacircle.dev/air-quality-apis/weatherbit/495-monthly-business-get-v2-0-forecast-airquality/llms.txt) are the best air quality API providers in our benchmark.

- This page: https://datacircle.dev/air-quality-apis/world-weather-online/free
- [Best air quality API in 2026: pricing compared](https://datacircle.dev/best-air-quality-api.txt)
- Get it: https://www.worldweatheronline.com/weather-api/api/pricing.aspx
- Request: `GET https://api.worldweatheronline.com/premium/v1/weather.ashx`
- API key: with the plan, on https://www.worldweatheronline.com/weather-api/api/pricing.aspx
- Its API docs: https://www.worldweatheronline.com/weather-api/api/docs/local-city-town-weather-api.aspx
- Sold by: World Weather Online (https://www.worldweatheronline.com)
- Checked: 2026-10-30

## In the answer

- Completeness: 33%
- Particles: ✓
- Gases: ✓

## Price

- $ per 1,000 places: $0.00
- Per: call
- Billing: free

## Charges

- Also pays for: from the same budget: Local History API · Marine Weather API · Marine History API · Ski Weather API · Search API · Astronomy API · Time Zone API

## Not found

- $ per 1,000: $0.00

## In their words

- Their pitch: Real-time air pollution data including PM2.5, PM10, ozone, NO₂, SO₂, and CO concentrations for health-conscious apps and environmental monitoring solutions.

## Data

- Keep data: You may cache API responses for performance optimisation subject to the following limits: current conditions data — maximum 60 minutes, forecast data — maximum 24 hours, historical data — no restriction. Caching beyond these limits or storing data beyond your subscription term constitutes a breach of these Terms and Conditions.
- Use data: WorldWeatherOnline grants you a limited, non-exclusive, non-transferable right to access and use the Weather API services for your own internal business or personal purposes, subject to these Terms and Conditions and your selected subscription plan. Free API access is permitted for both commercial and non-commercial use within the stated request limits. Free API users must credit WorldWeatherOnline by name or brand logo as the source of data in all public displays. [...] You may not transfer, sublicense, resell, or redistribute the API service or raw data feeds to any third party without prior written consent from WorldWeatherOnline. Any use of the API beyond the scope of your subscription plan — including exceeding request limits or accessing endpoints not included in your tier — is prohibited and may result in account suspension. Attribution required for public display of weather data [...] Where you make weather data derived from the WorldWeatherOnline API available to your own end users — whether through a website, mobile application, API, dashboard, or any other channel — you must display a clear, conspicuous disclaimer to those end users.

## Plan

- Pay: $0

## Rate limit

- Batch: 1

## The call

- You send: q, aqi "yes". Optional: num_of_days, date, tp, fx, cc, fx24, extra, includelocation, showlocaltime, showmap, lang, date_format
- Method: GET
- Path: /premium/v1/weather.ashx

## About the plan

- Plan: Free
- Who can get it: anyone aged 16 or over

## The 16 fields the plan's answer can hold

time read, day, hour, US EPA index, UK DEFRA index, PM2.5 concentration, PM10 concentration, ozone concentration, nitrogen dioxide concentration, sulfur dioxide concentration, carbon monoxide concentration, area name, country, region, latitude, longitude

## World Weather Online's plans (3)

- [World Weather Online, free](https://datacircle.dev/air-quality-apis/world-weather-online/free/llms.txt): $0.00 per 1,000, 33% complete
- [World Weather Online, $1 monthly, Pro, GET /premium/v1/weather.ashx](https://datacircle.dev/air-quality-apis/world-weather-online/1-monthly-pro-get-premium-v1-weather-ashx/llms.txt): $0.067 per 1,000, 33% complete
- [World Weather Online, contact us, Enterprise, GET /premium/v1/weather.ashx](https://datacircle.dev/air-quality-apis/world-weather-online/contact-us-enterprise-get-premium-v1-weather-ashx/llms.txt): 33% complete

## World Weather Online's calls (2)

- `GET /premium/v1/weather.ashx`: [World Weather Online, free](https://datacircle.dev/air-quality-apis/world-weather-online/free/llms.txt)
- `POST /premium/v1/weather.ashx`: [World Weather Online, $1 monthly, Pro, POST /premium/v1/weather.ashx](https://datacircle.dev/air-quality-apis/world-weather-online/1-monthly-pro-post-premium-v1-weather-ashx/llms.txt)

## World Weather Online's APIs (3)

- [World Weather Online: air quality API pricing, 3 plans](https://datacircle.dev/air-quality-apis/world-weather-online/free/llms.txt)
- [World Weather Online: current weather API pricing, 3 plans](https://datacircle.dev/current-weather-apis/world-weather-online/free/llms.txt)
- [World Weather Online: weather forecast API pricing, 3 plans](https://datacircle.dev/weather-forecast-apis/world-weather-online/free/llms.txt)

## World Weather Online: air quality API alternatives

- [Meteosource, $29 monthly](https://datacircle.dev/air-quality-apis/meteosource/29-monthly/llms.txt): $0.048 per 1,000, 33% complete
- [Foreca, €3,509 yearly, Altocumulus, GET /api/v1/air-quality/forecast/hourly/{location}](https://datacircle.dev/air-quality-apis/foreca/3509-yearly-altocumulus-get-api-v1-air-quality-forecast-hourly-location/llms.txt): $0.066 per 1,000, 33% complete
- [Open-Meteo, €99 monthly, API Professional, GET /v1/air-quality, Air quality, full](https://datacircle.dev/air-quality-apis/open-meteo/99-monthly-api-professional-get-v1-air-quality-air-quality-full/llms.txt): $0.067 per 1,000, 100% complete, live
- [API Ninjas, $1,188 yearly](https://datacircle.dev/air-quality-apis/api-ninjas/1188-yearly/llms.txt): $0.099 per 1,000, 33% complete

## Sources

From each provider's own pricing page and docs, and from what providers tell us. We read this row from these pages on 2026-10-30.

- https://www.worldweatheronline.com/weather-api/api
- https://www.worldweatheronline.com/weather-api/api/api-t-and-c.aspx
- https://www.worldweatheronline.com/weather-api/api/docs/local-city-town-weather-api.aspx
- https://www.worldweatheronline.com/weather-api/api/free-api-terms.aspx
- https://www.worldweatheronline.com/weather-api/api/local-city-town-weather-api.aspx
- https://www.worldweatheronline.com/weather-api/api/pricing.aspx