Wonder what's going on, they've been down a couple times in the last week.
And they offer a model with a SD Card so you can have local data too.
Also, I've found it pretty good at sensing pollution. For what it is, I think it's pretty good.
Also, I think the inventor was working on getting those numbers down, but of course a $250 item will never compare in accuracy to a $25K machine. It's one of those "good enough" thing I guess.