We don't usually think about manhole covers in terms of better designs or usefulness for environmental issues. But that's a bit of a shame because the things are all over the place and offer a perfect opportunity to be useful as sensors or other data-gathering functions. Luckily designers Wang Yi and Ji Ze have taken them into consideration and have come up with a manhole cover design that would be both a pollution safety indicator and they would harness energy to be used by maintenance workers.
The first use makes a lot of sense. These would be idea for collecting data on pollution levels and displaying those levels to pedestrians. The only problem is that they are low to the ground and the location could skew levels just slightly more than if the sensors were higher up where more air is circulating.
The second use, however, is far less realistic or useful. Yanko Design states, "Secondly it acts as a hub to harness biogas and kinetic energy that can be used by maintenance workers for their equipments, when they require it." The designers might be a little too hopeful about that one. There's very little likeliness that a manhole could gather any significant amount of electricity, especially enough to be used by maintenance workers with their heavy machinery.
If we delete that second notion, then the design is certainly an interesting concept that could be tested out as a prototype somewhere.