Plume Labs has been working on air pollution for a while. In addition to its mobile app and air quality device, the startup is launching a paid API called Plume.io so that anybody can add air quality to their own service. Think about it as Dark Sky’s API, but for air quality.

Plume Labs has designed its own algorithm to predict air pollution around the world. The company relies on 12,000 environmental monitoring stations in 60 countries. Many agencies and local authorities share air quality data.

The company then combines this data with other factors, such as the time of the day, weather conditions, weather forecasts, geographical specifics and human activities. Plume Labs can always compare its predictions with actual pollution levels by waiting and pulling data later in the day.

And it turns out that many companies would like to use this sort of forecast for air quality. That’s why the company is opening up its API to third-party companies. You can get data for Particulate Matter (PM2.5 and PM10), Nitrogen Dioxide (NO2) and Ozone (O3) starting at $500 a month.

Many companies are interested in Plume.io, such as companies working on smart homes and smart cities, real estate companies, fitness companies, healthcare companies as well as cosmetics makers. And Plume Labs will also give free access to Plume.io to researchers, activists, etc.

“We believe that environmental health is deeply personal and an important emerging vertical for personal health and wellbeing, so our Air Report mobile app and our consumer air quality tracker will remain our core focus,” co-founder and CEO Romain Lacombe told me. “However more and more companies were reaching out to access our air quality forecasts, and opening the Plume API will give these corporate clients access to our advanced predictive platform. Working with API partners will also bring financial support to keep our core app free for consumers, and dramatically broaden our reach to raise awareness of the public health crisis of pollution.”

So if you’ve been using Plume Labs’ mobile app, it’s not going away any time soon. And you’ll also soon be able to pre-order a Flow, Plume Labs’ own device. Plume.io is just a new service for developers who need air quality data. In the future, Plume Labs would like to extend forecasting data beyond 24 hours and add other data points, such as pollen level.