Findings of a new study have showed that levels of airborne microscopic particles increase because of July 4 fireworks around the country. For the study, the researchers looked into 315 locations and found that level of those particles at 9 p.m. and 10 p.m. on July 4 was double than normal, on average.

Results of smaller studies are also in line with this study, showing links between fireworks and particle pollution.

The study did not focus on any adverse effects on health because of high levels of airborne microscopic particles, said Dian Seidel of the National Oceanic and Atmospheric Administration. He reported the results in the journal Atmospheric Environment.

The study results led the Environmental Protection Agency to note Tuesday that health risk looms over children, older adults, and people with heart disease, asthma or other lung diseases because of particle pollution.

Dust, dirt, soot, smoke and liquid droplets make tiny particles known as particulate matter, said the Environmental Protection Agency. The agency has said that people can enjoy their local fireworks displays, but be a little careful to avoid any bad health effects.

Coughing, wheezing and shortness of breath, asthma attacks, heart attack and stroke could be experienced by those exposed to fine particles for longer durations.

"These results will help improve air quality predictions, which currently don't account for fireworks as a source of air pollution", said Seidel.

Health officials have suggested those who are affected by the particles must watch fireworks from upwind.