What they are made of
No material identifications yet.
What these numbers can and cannot say
- Counts are raw. Control samples (nets and filters exposed without sampling) were collected and are shown alongside the data, but nothing has been subtracted from the sample counts.
- Concentrations count the particles that passed a hot-needle melt test (the lab's basis); every particle picked is available in the Advanced view.
- Manta nets sample the surface and keep particles larger than the mesh (330 µm, about a third of a millimetre). Smaller particles are not counted here.
- Data describe specific sites and dates; they are not a bay-wide or year-round average, and they say nothing about health or safety.