In environmental and industrial sectors, "OOOO" (often pronounced "four-O" or "oh-oh-oh-oh") refers to EPA standards for the oil and gas industry:
That was the year of the aftermath. It was the vaccine rollout, the second year of lockdowns for many, and a time of deep existential exhaustion. It was a year where we looked up and realized nearly a decade had vanished, and we weren't entirely sure who we were anymore. oooooh 2013 2021