The available datasets are described here.
The Urbansense Air Quality dataset consists of air pollution sensing data reported by low cost sensor devices designed by the University of Helsinki. The devices are stationary and located in and around the Kumpula campus area. The map below shows the locations of currently deployed sensors. All the devices are measuring outdoor air.
University of Helsinki has developed portable air quality sensing devices in the HOPE project. Several measurement campaigns have been conducted using these devices in which recruited citizens of Helsinki have been carrying the devices for a period of time. The resulting data is available as grid based aggregates.