Ozone Exposure Risk Calculator

Formula: Introduction: Ozone exposure screening model

This calculator estimates two separate educational quantities: an ambient ozone benchmark comparison and an estimated inhaled dose. Ambient ozone risk is usually discussed with air-quality benchmarks such as the U.S. EPA 8-hour ozone standard, while inhaled dose depends on breathing rate, exposure duration, and body weight. These are related, but they are not the same thing.

The output is not a medical diagnosis, treatment recommendation, occupational exposure determination, or regulatory compliance finding. People with asthma, chronic respiratory disease, children, older adults, and people exercising outdoors may be more sensitive than a simple screening model can show.

Source metadata: benchmark source: U.S. EPA ozone National Ambient Air Quality Standard, 8-hour concentration of 70 ppb; data year/effective basis: current standard retained in EPA ozone NAAQS materials; last updated for this calculator: May 13, 2026. Limitation: the dose conversion assumes ozone molecular weight 48 g/mol and 24.45 L/mol at about 25 C and 1 atm.

Inputs and units

1. Enter an ozone concentration in ppb or micrograms per cubic meter.
2. Enter breathing rate in cubic meters per hour. Resting adults are often below heavy-exercise values, so choose a scenario that matches the activity.
3. Enter exposure duration in hours.
4. Enter body weight in kilograms.

All numeric inputs must be finite and greater than zero. Defaults, if your browser supplies them, are examples only.

Effective dose model used

Plain-text formulas:

• concentrationUgM3 = concentrationPpb * 48 / 24.45 when converting ppb to micrograms per cubic meter.
• concentrationPpb = concentrationUgM3 * 24.45 / 48 when converting micrograms per cubic meter to ppb.
• inhaledVolumeM3 = breathingRateM3h * durationHours
• estimatedMassUg = concentrationUgM3 * inhaledVolumeM3
• doseUgKg = estimatedMassUg / bodyWeightKg
• ambientBenchmarkRatio = concentrationPpb / 70

Worked ozone example

For an 8-hour scenario at 70 ppb ozone, with breathing rate 0.8 m3/hour and body weight 70 kg:

• concentrationUgM3 = 70 * 48 / 24.45 = 137.42 micrograms/m3
• inhaledVolumeM3 = 0.8 * 8 = 6.4 m3
• estimatedMassUg = 137.42 * 6.4 = 879.49 micrograms
• doseUgKg = 879.49 / 70 = 12.56 micrograms/kg
• ambientBenchmarkRatio = 70 / 70 = 1.00

How to interpret the result

The benchmark ratio compares the entered ambient concentration with a population-level 8-hour ambient air standard. It does not prove an individual outcome. The inhaled dose estimate is a physical intake estimate, not an AQI category and not a diagnosis.

Use the result to decide whether to reduce exposure, choose cleaner-air times or locations, improve ventilation/filtration where appropriate, or consult air-quality and medical professionals for higher-risk situations.

How to use this calculator

1. Enter Ozone concentration using the unit or time period shown by the field.
2. Enter Concentration unit using the unit or time period shown by the field.
3. Enter Breathing rate (m3/hour) using the unit or time period shown by the field.
4. Run the calculation and compare the output with a second scenario before acting on it.

Limitations and assumptions

This tool is a planning estimate, not a complete model of every edge case. Results depend on accurate inputs, current rates or rules, and consistent units. It does not replace local policy, professional review, or source data that may change over time.