1.90×105ppm1.90 \times 10^{5} \mathrm{ppm}1.90×105ppm
1.90×103ppm1.90 \times 10^{3} \mathrm{ppm}1.90×103ppm
1.16×104 ppm1.16 \times 10^{4} ~\mathrm{ppm}1.16×104 ppm
2.90×105ppm2.90 \times 10^{5} \mathrm{ppm}2.90×105ppm