They also only implement serial sending (so the Arduino receives) so far, although they mention the next step would be to build the other side of the connection.

An Arduino Uno provides the processing power and drives the serial monitor. A joystick and a Hitachi H48C accelerometer are mounted on a breadboard and wired to the Uno.

Now you can build your own room temperature monitor using an Arduino board. The circuit is a combination of an Arduino UNO board, LM35 temperature sensor, and a 16×2 Hitachi compatible LCD. It will ...

Full instructions on how to build your very own DIY Arduino air pollution monitor have been kindly published to the Thingyverse website and can be accessed via the link below.

He uses a cheap, $12 sensor with an Arduino and a Radiation shield and monitors the data on his computer.