In the wake of Monday’s bombing of the Boston Marathon, staff at the Willard Intercontinental hotel in downtown Washington drafted a letter Tuesday to guests alerting them to the fireworks scheduled that night as part of the District’s Emancipation Day celebration.

The notice was meant to prevent visitors from being alarmed by the booming noise.

Meanwhile, spokesmen for Hilton Worldwide and Marriott International said their companies had beefed up security at local hotels and at other properties nationwide.

Sports fans and concertgoers might notice changes in procedure at upcoming events. A spokesman for Monumental Sports & Entertainment said Tuesday that security at Verizon Center events will be “enhanced” following the terrorist attack. The entertainment venue, which hosts the Washington Wizards and Capitals as well as dozens of other events, requires patrons to empty pockets, undergo bag searches and go through security-wand checks.

But it will do more.

“We also will institute measures that will be readily visible to the public as well as some that are not, but all will add to the safety and security of our patrons,” the team said in a statement.

Businesses in the Washington area’s travel and event industry are taking fresh steps to ensure that visitors feel safe, mindful of the hit the sector took after the Sept. 11, 2001, terrorist attacks. Airlines, in particular, hemorrhaged jobs and revenue as would-be travelers remained on the sideline, unsure about whether it was safe to take a trip.

“Terrorism has had effects historically on travel, but until we know more about exactly what happened, I don’t know that you could really make a judgment call on how it would affect travel going forward,” said Mike McKean, founder and chief executive of the Knowland Group, a District-based data company that gathers information on meetings and events in the travel industry.

Gloria Bohan, founder and president of Omega World Travel in Fairfax, worried the bombings could discourage some from attending big events.

The bombing “causes doubt, apprehension. It’s got to have an economic impact,” Bohan said, especially if the hassles of entering the United States dissuade foreigners from vacationing here.

Still, because this week’s attack took place in a public space, and not on airplane or other form of transport, it may not deal a blow to the travel industry in the same way that the Sept. 11, 2001, attacks did. Indeed, that seemed to be the view of investors. Indexes that track airline and hotel stocks fell roughly 4 percent on Monday before bouncing back Tuesday.

“I don’t think travelers will at all be concerned about this,” said Fred Malek, chairman of Thayer Lodging, a private equity firm that invests in the hotel industry. “It’s an isolated incident and not related to travel.”

Destination D.C., a tourism marketing organization for the region, said that Tuesday was mostly business as usual for it. Robin McClain, the organization’s director of communications, said the group’s visitor information number received three phone calls Tuesday inquiring about any repercussions here.

“We really aren’t handling anything differently, we’re just trying to assure anyone that may inquire that Washington is at a heightened state of alert,” McClain said, but that its tourist attractions remain open and ready for business.

Their hope, McClain said, is that travelers are receptive to their message.

“Our hearts go out to the folks that are affected yesterday by what happened,” McClain said. However, “People in the tourism industry, we don’t want the takeaway to be to not go and travel and have those experiences that can be so great.”