# Tomorrow.io, contact us: Air quality API

> Understand what precautions to take with respect to pollution, meet EPA standard regulations, and plan your outdoor activity.

Tomorrow.io's air quality API on its Enterprise plan. It returns 3 of the 6 key fields we check: US AQI, 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/tomorrow-io/contact-us
- [Best air quality API in 2026: pricing compared](https://datacircle.dev/best-air-quality-api.txt)
- Get it: https://www.tomorrow.io/weather-api/
- Request: `POST https://api.tomorrow.io/v4/timelines`
- API key: with the plan, on https://www.tomorrow.io/weather-api/
- Its API docs: https://docs.tomorrow.io/reference/post-timelines
- Sold by: Tomorrow.io (https://www.tomorrow.io)
- Checked: 2026-10-30

## In the answer

- Completeness: 50%
- US AQI: ✓
- Particles: ✓
- Gases: ✓

## Price

- Billing: contact

## Charges

- Also pays for: from the same budget: Realtime Weather · Weather Forecast

## In their words

- Their pitch: Understand what precautions to take with respect to pollution, meet EPA standard regulations, and plan your outdoor activity.

## Data

- Keep data: "store or otherwise collect or copy the unaltered Datafeed, unless otherwise expressly provided for in the Order or for permitted evaluation of DaaS, in which case Datafeed may only be stored for the duration of the Initial Term [...]" (terms, Restrictions).
- Use data: "Paid Solution offerings may be used for Subscriber's internal business purposes or, as specified in an Order, integrated into Subscriber proprietary commercial applications. Commercial use is strictly prohibited in the case of evaluation, proof of concept, or in connection with self-generated accounts originated on Company's website [...] The Solution may not be distributed, shared, or offered on a standalone basis" (terms, Permitted Use), "any portion of the Solution that incorporates and presents Datafeed shall prominently display the message "Powered by Tomorrow.io" in a legible manner near such data or any information derived from it" (terms, Attribution), "Subscriber acknowledges and agrees not to engage, directly or indirectly, or facilitate engagement by a third party, in the following prohibited activities: [...] Use the Solution to develop, or create, or permit others to develop or create, a product or service in any way similar or competitive to the Solution, as solely determined by Company, Offer any portion or all of the Solution to any third parties [...] including but not limited to reselling, licensing, renting, leasing, transferring, lending, timesharing, assigning or redistributing it or any part thereof or generating revenue thereform. [...] Use robots, crawlers and similar applications to scrape, harvest, collect or compile content or data from or through the Solution, Publish or disclose the results of any benchmark tests performed with respect to the Solution or otherwise use any testing results related to the Solution for commercial, competitive, or other purposes" (terms, Restrictions).

## Rate limit

- Batch: 1

## The call

- You send: fields, Accept-Encoding header "deflate, gzip, br". Optional: location, units, timesteps, startTime, endTime, timezone, dailyStartHour
- Method: POST
- Path: /v4/timelines

## About the plan

- Plan: Enterprise
- Who can get it: anyone

## The 17 fields the plan's answer can hold

timestep, start time, end time, interval start time, PM2.5, PM10, ozone, nitrogen dioxide, carbon monoxide, sulfur dioxide, China MEP AQI, China MEP primary pollutant, China MEP health concern, US AQI, US AQI primary pollutant, US AQI health concern, wildfire smoke index

## Tomorrow.io's plans (1)

- [Tomorrow.io, contact us](https://datacircle.dev/air-quality-apis/tomorrow-io/contact-us/llms.txt): 50% complete

## Tomorrow.io's calls for this API (1)

- `POST /v4/timelines`: [Tomorrow.io, contact us](https://datacircle.dev/air-quality-apis/tomorrow-io/contact-us/llms.txt)

## Tomorrow.io's APIs (3)

- [Tomorrow.io: current weather API pricing, 2 plans](https://datacircle.dev/current-weather-apis/tomorrow-io/free/llms.txt)
- [Tomorrow.io: weather forecast API pricing, 2 plans](https://datacircle.dev/weather-forecast-apis/tomorrow-io/free/llms.txt)
- [Tomorrow.io: air quality API pricing, 1 plan](https://datacircle.dev/air-quality-apis/tomorrow-io/contact-us/llms.txt)

## Tomorrow.io: air quality API alternatives

- [WeatherAPI.com, contact us](https://datacircle.dev/air-quality-apis/weatherapi-com/contact-us/llms.txt): 50% complete, live
- [Weatherbit, contact us, Enterprise, GET /v2.0/forecast/airquality](https://datacircle.dev/air-quality-apis/weatherbit/contact-us-enterprise-get-v2-0-forecast-airquality/llms.txt): 50% complete
- [ReefAPI, contact us](https://datacircle.dev/air-quality-apis/reefapi/contact-us/llms.txt): 50% complete, live
- [IQAir, contact us, Enterprise, GET /v2/nearest_city](https://datacircle.dev/air-quality-apis/iqair/contact-us-enterprise-get-v2-nearest-city/llms.txt): 50% complete
- [Meteomatics, contact us](https://datacircle.dev/air-quality-apis/meteomatics/contact-us/llms.txt): 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://docs.tomorrow.io/reference/data-layers-air
- https://docs.tomorrow.io/reference/post-timelines
- https://docs.tomorrow.io/reference/rate-limiting
- https://docs.tomorrow.io/reference/timeline-overview
- https://www.tomorrow.io/terms-of-service/
- https://www.tomorrow.io/weather-api/