Concentration - Units Conversions

1.) is 47.8 ng/L = 0.0478ppb?

and if so

would that above concentration be above

10,000 ug/L (what would this be in ppb)

2.) is 6.77 ng/m^3 = 0.0066 ppb?

an if so, would that exceed

0.5-5g/Kg for a 70 kg person (which is a lethal concentration) (and what would this be in ppb)

and would that exceed

Lethal concentration (50 percent kill): 2,485 mg/m3/4 hour... this is for a rat

3.) and finally what is

78.4 ng/g in ppb

and is it more then

Lethal dose (50 percent kill): 4 gm/kg (and what would this be in ppb)