1. What is Percent Transmittance?

Definition: Percent transmittance (%T) measures how much light passes through a medium (like air) compared to the initial light intensity.

Purpose: It helps quantify air clarity, pollution levels, and the transparency of the atmosphere for various applications.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \%T \) — Percent transmittance (%)
• \( I \) — Transmitted intensity (W/m²)
• \( I_0 \) — Incident intensity (W/m²)

Explanation: The ratio of transmitted to incident light intensity is multiplied by 100 to get a percentage value.

3. Importance of Percent Transmittance

Details: Measuring %T is crucial for atmospheric studies, pollution monitoring, optical measurements, and understanding light attenuation in air.

4. Using the Calculator

Tips: Enter both intensity values in W/m². The transmitted intensity must be less than or equal to the incident intensity.

5. Frequently Asked Questions (FAQ)

Q1: What does 100% transmittance mean?
A: 100% means all incident light passes through with no absorption or scattering (perfectly clear air).

Q2: What's a typical %T value for clean air?
A: Clean air typically has %T values close to 100% for visible light, varying with wavelength and path length.

Q3: How does pollution affect %T?
A: Pollutants (particulates, smog) decrease %T by absorbing and scattering light.

Q4: What instruments measure these intensities?
A: Spectrophotometers, photometers, or light meters measure light intensities.

Q5: Does this account for different wavelengths?
A: This is a general calculation - specific wavelengths may have different transmittance values.