Parts Per Million — Definition, Formula, Properties & Uses | AllChemicals | AllChemicals

Q: What is the formula for Parts Per Million?

The formula or notation for Parts Per Million is: ppm = mg/L (water) or mg/kg; = (mass solute/mass solution) × 10⁶

Formula / Notation	ppm = mg/L (water) or mg/kg; = (mass solute/mass solution) × 10⁶
Also Known As	ppm, parts per million, mg/L, mg/kg, μg/mL, concentration unit

What is Parts Per Million?

A concentration unit (ppm) expressing the number of parts of a substance per million parts of the mixture. Used for trace quantities of contaminants in water, air, and solutions. 1 ppm = 1 mg/kg or 1 mg/L for aqueous solutions. Related units: ppb (parts per billion).

Formula & Notation

ppm = mg/L (water) or mg/kg; = (mass solute/mass solution) × 10⁶

Other Names / Synonyms: ppm, parts per million, mg/L, mg/kg, μg/mL, concentration unit

Properties & Characteristics

Parts per million (ppm) is a dimensionless concentration unit expressing the ratio of the amount of a solute to the total amount of the solution, multiplied by 10⁶. In aqueous solutions: 1 ppm ≈ 1 mg/L (mg per litre of water). In air: 1 ppm = 1 mL/m³ (by volume) or expressed in mg/m³ (by mass). For solid mixtures: 1 ppm = 1 mg/kg. Parts per billion (ppb = 10⁻⁹), trillion (ppt = 10⁻¹²), and billion (ppb) are used for trace analysis.

Uses & Applications

ppm is used in: expressing trace contaminant concentrations (drinking water standards: arsenic 10 ppb, lead 10 ppb), occupational exposure limits (CO: 25 ppm TLV, Cl₂: 0.5 ppm TLV), environmental monitoring (SO₂ in air, mercury in fish), spectroscopic calibration (NMR chemical shift in ppm relative to TMS), and analytical chemistry detection limits.

Safety Information

At ppm concentrations, many substances are acutely toxic (HCN: IDLH = 50 ppm; H₂S: IDLH = 100 ppm; phosgene: IDLH = 25 ppm). The very low concentrations at which some compounds pose hazards make sensitive analytical detection essential in environmental and occupational health monitoring.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Parts Per Million

Formula ppm = mg/L (water) or mg/kg; = (mass solute/mass solution) × 10⁶

Index All "P" terms

Synonyms ppm, parts per million, mg/L, mg/kg, μg/mL, concentration unit

Frequently Asked Questions

What is Parts Per Million?

A concentration unit (ppm) expressing the number of parts of a substance per million parts of the mixture. Used for trace quantities of contaminants in water, air, and solutions. 1 ppm = 1 mg/kg or 1 mg/L for aqueous solutions. Related units: ppb (parts per billion).

What is Parts Per Million used for?

Is Parts Per Million hazardous?

What is the formula for Parts Per Million?

More "P" Terms

P-type Semiconductor Pairing Pairing Energy Palladium Pd Parachor [P] = M(γ)^(1/4) / (ρ_L - ρ_V) Paramagnetic χ_m > 0; unpaired electrons; μ = √(n(n+2)) BM (n = unpaired electrons) Paramagnetism Partial Ionic Character % ionic = (1 - e^(-Δχ²/4)) × 100% Partial Pressure Partial Pressure p_i = x_i × P_total; P_total = Σp_i Particulate Matter Pauli Exclusion Principle

View all "P" terms →