165.5 ppb to ppm

165.5 ppb = 0.166 ppm

ppbppm
150.5 ppb0.15
155.5 ppb0.155
160.5 ppb0.161
165.50.166
170.5 ppb0.171
175.5 ppb0.176
180.5 ppb0.18

165.5 ppb = 0.166 ppm

Formula

1 ppm = 1 mg/L (aqueous, density ≈ 1 kg/L) · 1 ppb = 0.001 mg/L · 1% = 10,000 ppm