Yes that might be a good idea but I am very happy that so many people are interested in building one and that we can increase the awareness on air quality so I am happy to do the work ;)

Yeah, this is an interesting enough problem to me that I recently started researching how to build an arduino version of what this person is offering - in my head, I basically reinvented the product they're offering, without all of the nasty bits of actually having any idea how it works. I would definitely pay a reasonable amount of money for a set of sensors that Just Worked that would collect data in my house.