Can particle birth be limited to a specific area, then allowed to move outside that area?

[AbeVigo]

Wondering if it is possible to limit particle birth to a specific area - for example, the bottom 25% of the canvas - then allow the birthed particles to move outside that area?

Ideally, not all particles would float up to the top, but a smaller portion. Possibly basing this on lifespan so all particles don't survive long enough to float up.

Here's an image to help illustrate the idea:

[matteobruni]

You can se a lot of samples of different sized emitters on my CodePen (https://codepen.io/matteobruni)

Here some samples:

https://codepen.io/matteobruni/pen/eYBaGxy
https://codepen.io/matteobruni/pen/NWRPKQW
https://codepen.io/matteobruni/pen/KKMrPON
https://codepen.io/matteobruni/pen/PoZgQea <-- this is a full screen emitter, particles will be created on all canvas area so you can see different emitters size options

[AbeVigo]

Thank you for the fast and helpful reply! The example at https://codepen.io/matteobruni/pen/NWRPKQW is right where I need to start.

Thanks again