Calculator Inputs
Use presets for quick estimates, or switch to custom values for detailed planning.
Example Data Table
Sample scenarios to illustrate typical use. Values are illustrative and depend on your site conditions.
| Scenario | Area (m²) | Height (m) | Duration (h) | Preset | Control (%) | Wind / ACH | Total mass (g) | Avg conc. (mg/m³) |
|---|---|---|---|---|---|---|---|---|
| Outdoor moderate cutting | 500 | 3 | 4 | Moderate | 40 | 2.5 m/s | 720.00 | 0.0780 |
| Indoor heavy grinding | 200 | 3 | 2 | Heavy | 60 | 10 ACH | 280.00 | 0.1550 |
| Outdoor demolition burst | 800 | 4 | 1 | Demolition | 30 | 3.5 m/s | 2352.00 | 0.1140 |
Formula Used
1) Emission rate
E (mg/s) = EF (mg/m²/s) × Area (m²) × Activity × (1 − Control%)
2) Total emitted mass
M (mg) = E (mg/s) × Duration (s)
3) Mixing volume
V (m³) = Area (m²) × Mixing height (m)
4) Removal rate
λ (1/h) = Exchange (1/h) + Deposition (1/h)
5) Concentrations (mass balance)
Css (mg/m³) = E (mg/h) ÷ [λ (1/h) × V (m³)]
Cavg = Css × [ 1 − (1 − e−λT) ÷ (λT) ]
Outdoor exchange estimate
Exchange ≈ k × (Wind ÷ √Area) × 3600
The factor k adjusts how strongly wind refreshes the mixing volume.
How to Use This Calculator
- Choose Outdoor for open sites, or Indoor for enclosed spaces.
- Enter the working area, mixing height, and exposure duration.
- Select a preset, then adjust the activity multiplier for intensity.
- Set control efficiency to reflect dust suppression measures.
- Tune wind/ACH and deposition rate to match ventilation and settling.
- Click Calculate, then export CSV/PDF for reporting.
Dust Load as a Planning Metric
Airborne dust load quantifies how much particulate mass becomes suspended during construction activities. Estimating load helps compare tasks, schedule controls, and document decisions for safety. The calculator converts an emission factor per square meter into a site emission rate using area, activity intensity, and control efficiency. Results provide total emitted mass, average concentration, and steady state concentration over the selected exposure period for reporting for teams.
Source Controls and Efficiency
Controls reduce emissions at the source and usually deliver the largest benefit on busy projects daily. Water misting, foam, surface wetting, covered conveyors, and localized capture can be represented with a control efficiency percentage. The model applies this efficiency directly to the emission rate, so a forty percent control reduces both total mass and concentrations by forty percent. Pair controls with housekeeping to prevent re suspension.
Ventilation, Dilution, and Removal
Ventilation and dilution govern how quickly airborne dust is removed from the mixing volume. For indoor spaces, air changes per hour represent mechanical ventilation or open door exchange. For outdoor sites, wind speed and a dispersion factor estimate how rapidly air refreshes a characteristic area. The calculator combines exchange with deposition losses to form a total removal rate, improving realism versus simple mass divided by volume.
Particle Fractions and Dose Insight
Particle size fractions matter because health impacts and regulatory focus differ across ranges on most sites. PM10 represents inhalable particles, while PM2.5 represents finer particles that penetrate deeper into the lungs. The calculator splits total mass by user defined fractions and can estimate an inhaled dose using breathing rate and optional respirator efficiency. Use monitoring data, material tests, and observations to tune fractions before final deployment.
Using Results for Reporting
Outputs are best used for relative comparisons, planning, and communication rather than absolute compliance determinations alone. Calibrate emission factors to materials, moisture, equipment, and work practices, then run scenarios for different controls and schedules. Exported CSV and PDF summaries support toolbox talks, method statements, audits, and client reporting. Re run calculations when weather, ventilation, or activity intensity changes during shifts and update assumptions in documentation promptly.
FAQs
1) What does the emission factor represent?
It is the dust mass released per square meter per minute for a given activity. Use presets for quick planning or set a custom factor from site measurements or supplier guidance.
2) Why do concentration results change with wind or ACH?
Wind and ACH estimate how fast fresh air replaces dusty air. Higher exchange increases removal, lowering average and steady state concentrations for the same dust generation.
3) How should I choose the mixing height?
Use the effective air layer where dust is expected to mix. Indoors, use room height. Outdoors, use a practical near field height based on work elevation and dispersion conditions.
4) Does control efficiency affect all outputs?
Yes. It reduces the emission rate before dilution is applied, so total emitted mass and modeled concentrations drop proportionally. Respirator efficiency affects only the inhaled dose estimate.
5) Are PM fractions always known?
Not always. Start with conservative estimates, then refine using monitoring, material characteristics, and moisture conditions. Keep PM10% plus PM2.5% at or below one hundred percent.
6) Can I use this for regulatory compliance decisions?
Use it for screening, planning controls, and documenting assumptions. For compliance, compare against your applicable standards using calibrated inputs, validated monitoring, and professional industrial hygiene review.