What does the term 'airburst' refer to in pyrotechnics?

The term 'airburst' in pyrotechnics specifically describes a type of pyrotechnic device that is designed to explode in the air rather than on the ground. This is significant for creating visual effects such as colorful bursts and patterns that are visible to the audience from a distance, as the explosion takes place above the ground level. Airbursts are carefully designed to release their effects at a predetermined height, which enhances the visual spectacle of fireworks displays, making them a popular choice for professional performances.

By contrast, the other options describe different aspects of pyrotechnics. Hazardous debris typically comes from devices that may not be designed for safe aerial effects. Devices that explode on the ground do not match the definition of an airburst, as they lack the aerial aspect pivotal to that term. Lastly, handheld fireworks are distinct entities that are meant to be held by users and ignited, which is unrelated to the concept of an airburst in terms of its aerial explosion characteristics.