As of my last update in January 2022, there isn't a widely recognized "National Fart Day" celebrated in the United States or globally. While the topic of flatulence occasionally garners attention in humorous contexts, it hasn't been formalized into an official holiday or observance.
However, in a lighthearted sense, some individuals or groups may choose to celebrate a day dedicated to humor or comedy, including playful references to bodily functions like farting. Keep in mind that any such celebration would likely be informal and may vary widely in its observance and acceptance depending on cultural norms and personal preferences.
If you're interested in commemorating such a day, it's important to approach it with humor and sensitivity, respecting the boundaries and comfort levels of others. Additionally, creating a day focused on laughter and joy can be a fun way to bring people together, as long as it's done in good spirits and with mutual respect.