PPT to PPM conversion

How to convert PPT to PPM:

1ppm = 1/10⁶ = 10^-6

1ppt = 1/10¹² = 10^-12

So

1ppm = 10⁶ppt

The number of parts-per million x_ppm is equal to the number of parts-per trillion x_ppt divided by 10⁶:

x _ppm = x _ppt / 10⁶

Example:

7000ppt is equal to 0.007ppm:

x _ppt = 7000ppt / 10⁶ = 0.007ppm