1. What is a PPM to mg/m³ Calculator?

Definition: This calculator converts gas concentrations from parts per million (ppm) to milligrams per cubic meter (mg/m³).

Purpose: It helps environmental scientists, industrial hygienists, and safety professionals convert between these common concentration units.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( mg/m^3 \) — Concentration in milligrams per cubic meter
• \( PPM \) — Concentration in parts per million
• \( MW \) — Molecular weight of the gas (grams per mole)
• \( 24.45 \) — Molar volume of ideal gas at 25°C (liters per mole)

Explanation: The formula accounts for the molecular weight of the substance and the volume occupied by one mole of gas at standard conditions.

3. Importance of Unit Conversion

Details: Different regulations and instruments use different units, making conversion essential for compliance and accurate measurements.

4. Using the Calculator

Tips: Enter the PPM value and molecular weight of the gas. The calculation assumes standard conditions (25°C and 1 atmosphere pressure).

5. Frequently Asked Questions (FAQ)

Q1: Why is 24.45 used in the formula?
A: This is the molar volume (in liters) of an ideal gas at 25°C (298K) and 1 atmosphere pressure.

Q2: How do I find the molecular weight?
A: Check chemical reference tables or calculate by summing atomic weights of all atoms in the molecule.

Q3: Does temperature affect the conversion?
A: Yes, the 24.45 factor changes with temperature. For other temperatures, use: 24.45 × (298K/T), where T is temperature in Kelvin.

Q4: Can I convert mg/m³ back to PPM?
A: Yes, use the inverse formula: PPM = (mg/m³ × 24.45) / MW

Q5: Is this valid for all gases?
A: It works for ideal gases at standard conditions. For high pressures or non-ideal gases, additional corrections may be needed.