Air Quality Meter

Airatom Table-Top Air Quality Meter 

1) Purpose & Function

The Airatom Table-Top Air Quality Meter is designed to provide real-time monitoring of particulate matter (PM2.5 & PM10), carbon dioxide (CO₂), temperature, humidity, and the calculated Air Quality Index (AQI). It helps users assess indoor air quality, detect pollution events, and take corrective actions such as increasing ventilation or using air purification.

2) Measurement Principles

a) PM2.5 & PM10 (µg/m³)

• Principle: Laser Scattering

  • A laser beam passes through the sampled air.

  • Suspended particles scatter light at various angles.

  • A photodetector measures scattered light intensity, which correlates to particle concentration and size.

• PM2.5: Fine particles ≤ 2.5 µm, which penetrate deep into the lungs.

• PM10: Inhalable particles ≤ 10 µm, which can cause respiratory irritation.

• Significance: Elevated levels are linked to respiratory and cardiovascular problems.

b) CO₂ (ppm)

• Principle: NDIR (Non-Dispersive Infrared) Sensing

  • CO₂ molecules absorb infrared light at a wavelength of ~4.26 µm.

  • The reduction in light intensity is proportional to the CO₂ concentration.

• Range: 400–10,000 ppm (typical).

• Significance: High CO₂ (>1000 ppm) indicates inadequate ventilation and can cause fatigue, reduced concentration, and discomfort.

c) Temperature & Humidity

• Principle: Digital CMOS sensor

  • Temperature via bandgap or thermistor element.

  • Humidity via capacitive polymer sensor that changes dielectric constant with water vapor.

• Significance: Comfort metrics; also used for CO₂ compensation and PM sensor correction.

3) AQI (Air Quality Index)

• Definition: A standardized index that converts PM2.5 and PM10 concentrations into a single score for health interpretation.

• Color Coding on Display:

  • Green (0–50): Good

  • Yellow (51–100): Moderate

  • Orange (101–150): Unhealthy for sensitive groups

  • Red (151–200): Unhealthy

  • Purple (201–300): Very Unhealthy

  • Maroon (>300): Hazardous

• Purpose: Simplifies complex particulate data into an easy-to-understand visual indicator.

4) Device Features

• Real-Time Display: Large color LCD with clear readings for AQI, PM2.5, PM10, CO₂, temperature, and humidity.

• Trend Awareness: Continuous updates for changes in air quality.

• User Alerts: Visual AQI ring + optional buzzer for poor air quality or high CO₂.

• Portability: Compact, table-top design for home, office, classrooms, and labs.

• Ease of Use: Plug-and-play operation, no special installation required.

5) Application Scenarios

• Indoor air quality assessment in homes, offices, schools.

• Monitoring ventilation efficiency in conference rooms.

• Air purifier performance evaluation.

• Environmental health studies and awareness programs.

6) Health Reference Ranges

7) Working Summary

1. Air Inlet: Fan or convection draws ambient air into sensor chamber.

2. Sensing:

   • Laser scattering detects PM2.5 and PM10 levels.

   • NDIR measures CO₂ concentration.

   • Digital sensor measures temperature and humidity.

3. Processing: Microcontroller calculates AQI, applies compensation algorithms, and updates display.

4. Output: Values shown on LCD with AQI color ring; optional alerts when thresholds exceeded.