None of that "plan" or "test" actually needs to release any sulfur dioxide, especially because they don't seem to be doing any kind of measurements of the substance once released. Pretending this is anything but an intentional act of provocation isn't "pretty open about exactly what they're doing". This is really all somebody needs to read to know what is going on:

> Luke Iseman, a serial inventor and the former director of hardware at Y Combinator, believed all of that research was not happening fast enough. So he started tinkering with releasing sulfur dioxide particles into the atmosphere with balloons, raised venture capital to fund the startup, and brought on co-founder Andrew Song to manage sales.