At I/O, Google Will Be Tracking Things Like Noise Level And Air Quality With Hundreds Of Arduino-Based Sensors article tells that in the blog post, Michael Manoochehri, Developer Programs Engineer, outlines his team’s plan to place hundreds of Arduino-based environmental sensors around the conference space to track things like temperature, noise levels, humidity and air quality in real-time. This was spawned due to a fascination with wanting to know which areas of the conference were the most popular.
Data Sensing Lab at Google I/O 2013: Google Cloud Platform meets the Internet of Things page has some details on the plans. According to pictures the devices on the field use XBee wireless communications modules. Google App Engine Datastore, along with Google Cloud Endpoints, provides a scalable front end API for collecting data from devices. Google Compute Engine is used to process and analyse data with software tools such as R and Hadoop.
Google has history on using Arduino platform for different applications, good earlier example of that is Android Open Accessory Development Kit.