Fourth of July fireworks may be fun to watch, but along with all those festive sparks, these colorful pyrotechnics also suffuse the air with tiny particles that can be dangerous to our health, warn health officials in a new study published by the Environmental Protection Agency (EPA) and reported by Yahoo News.

For the study, EPA field workers measured levels of airborne microscopic particles at 315 Independence Day celebrations across the country.

Researchers found that between 9 and 10 p.m. on the holiday, quantities of these particles measured on average more than twice the normal level. (Levels of the particles returned to normal by noon the following day.)

But the agency’s warning wasn’t issued to suck the fun out of Fourth of July celebrations forever. “We want everyone to enjoy their local fireworks displays,” said an EPA statement.

The report simply advised that those who are sensitive to particle pollution, such as people with respiratory and cardiovascular issues, as well as children and elderly people, make sure they watch fireworks displays upwind of blast sites.

Now, here’s the real downer: Fireworks-related injuries send thousands of people to the hospital on the Fourth of July every year. Click here to read some safety tips.