The pupils decided to focus upon the three types of particulate matter (PM) due to the extreme health impacts they can have on people who are young, elderly and those with existing health conditions.
Penderfynodd y disgyblion ganolbwyntio ar y tri math o ddeunydd gronynnol oherwydd yr effaith eithafol gallant ei chael ar iechyd pobl ifanc, pobl oedrannus, a'r rhai sydd â chyflyrau iechyd.