The balloon, manufactured by Aerophile, is located in the Parc Andre Citroen in Paris, and is filled with 6,000 cubic meters of of helium.
It is meant to serve as both a tourist attraction and as an eco-awareness tool.
There are three projectors inside the balloon that light and color it. When the balloon is green the air is very clean; light green when clean; yellow for moderate; orange for polluted; and red means the air is highly polluted. 
Air pollution data is collected from around the city by sensors set up and monitored by Airparif, an organization that measures air quality in France. That data is used to decide the color of the balloon.
There’s also a high-powered rotating laser that sweeps along the lower half of the balloon to signify the amount of traffic pollution.
The balloon will also provide rides for up to 30 passengers at a time (non-polluting rides). Aerophile says “flight aboard a tethered gas balloon is a unique experience full of sensations for the passengers. Silent and without vibration, the gondola is open to the air, allowing passengers to experience the sensation of being on a flying balcony 150m in the sky. A 360 degree panorama unfolds before them, and in a single gaze they can take in the whole landscape.”
I don’t think a ride like that is for me. If it was completely quiet while I was riding in the air I would think something is broken and that a free fall towards the ground is imminent, meaning I would probably freak – something the other passengers probably wouldn’t appreciate.
Related posts: