If someone is a baal keri [they had a seminal emission], and they clean themselves, they remain contaminated until evening (Lev 15:16). What does that entail? Does being contaminated until evening mean they can't go to work without the fear of contaminating others?
After immersion from a first-order impurity, a person or vessel remains somewhat impure until sundown (called "Tevul Yom"). (Rambam, Shar Avot HaTumah 10:1)
A Tevul Yom who touched Terumah renders it third-order impure, and if they touch Temple sacrifices they render them fourth-order impure (ibid. :3). A Tevul Yom does not affect people, vessels, standard food (Rambam, Tumat Ochlin 7:7), second-tithe food (Rambam, Mishkav uMoshav 5:6), or ashes of the Red Heifer (Rambam, Parah 1:13).
Additionally, unlike other impurities, body fluids of a Tevul Yom are pure (Rambam, Avot HaTumah, 10:6). A Tevul Yom is prohibited rabbinically from entering even the outer parts of the Temple, but they may go on the Temple mount (Rambam, Biat Mikdash 3:6). A Kohein who is a Tevul Yom is still fully prohibited from serving in the Temple (ibid. 4:4).
Even in Temple times, from immersion until nightfall their status is called tvul yom. They're just ever-so-slightly "impure" enough that they can't touch holy food such as terumah or sacrifices, but touching people wouldn't do anything.
Today this is all pretty much a moot point anyhow, and the best practice (halachically and psychologically) is to get back to a normal routine right away.