Air analyzer PAX

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Overview
The PAX is a sensitive, high-resolution, fast-response instrument for direct in‑situ measurement of aerosol optical properties relevant to climate studies and carbon particle analysis.

FEATURES AND BENEFITS

• Direct in‑situ measurements – simultaneous, accurate measurement of light absorption and scattering in a single instrument to enable correlation with black carbon mass concentration.
• Autonomous continuous operation – no filter collection required, eliminating filter artifacts.
• Real‑time results – one‑second resolution and live data display on a high‑resolution touch screen.
• High sensitivity – excellent scattering sensitivity using a reciprocal wide‑angle nephelometer combined with photoacoustic absorption detection.
• Configurable wavelengths – standard 870 nm with optional 532 nm or 405 nm to target black carbon, visual-range observations, or organic/brown carbon.
• Lifecycle support option – instrument lifecycle care and maintenance program available.

TECHNOLOGY

• Modulated diode laser measures particle light scattering and photoacoustic absorption simultaneously.
• Photoacoustic principle: absorbing particles convert absorbed light to heat, producing pressure waves detected by a sensitive microphone to quantify light absorption.
• Reciprocal wide‑angle integrating nephelometer measures the light scattering coefficient across 6°–174°.
• Laser wavelength options:
  
  • 870 nm – absorption specific to black carbon (soot); optimal scattering response for larger particles.
  • 532 nm – visual‑range measurement similar to human eye response.
  • 405 nm – absorption correlated with organic/brown carbon; effective scattering for fine and ultrafine particles.

MAIN APPLICATIONS

• Visibility and fog research
• Human health and exposure studies
• Climate forcing and aerosol radiative studies

PAX Software

• Integrated control software with intuitive front‑panel touchscreen UI and web browser access on networked computers.
• Real‑time display of measured and derived data, instrument status and configurable operating parameters.
• Password‑protected remote access for full operation and configuration.
• Data output to easy‑to‑read ASCII files for download, archiving and external processing.
• Functions for uploading calibration data and performing maintenance tasks.

ACCESSORIES

• Hard‑shell shipping case for frequent transport.
• PM1.0 cyclone inlet (1 L/min) for particle size selection.
• PM2.5 cyclone inlet (1 L/min) for particle size selection.

CHARACTERISTICS / TECHNICAL SPECIFICATIONS

• Measured parameters: Absorption coefficient (Babs), Scattering coefficient (Bscat)
• Auxiliary parameters: Temperature, Pressure, Relative Humidity
• Derived parameters: Black carbon (BC) mass, Extinction coefficient (Bext), Single scattering albedo (SSA), Dew point
• Measurement range (absorption & scattering): < 1 Mm-1 – 10,000 Mm-1 (870 nm, 60 s averaging)
• Laser: 870 nm (1.4 W) standard; modulation frequency 1500 Hz nominal (square wave); optional 532 nm and 405 nm
• Angular integration for scattering: 6° to 174°
• Sample flow: 1 L/min. Flow control: critical orifice; diaphragm pump
• Response time: < 10 s; one‑second resolution
• Data averaging time: 1, 10 or 60 s (user selectable)
• Zero check: on demand or automated at user‑selectable intervals (5, 15, 20, 30, 60 min) using high‑efficiency filtered air
• Front panel: graphical color touch‑panel display, two USB‑A ports, power switch; UI via touch screen or keyboard
• Rear connections: sample inlet (compression fitting for 1/4" tube), pump exhaust (compression fitting for 1/4" tube), AC/DC power, RS‑232, Ethernet, two analog BNC inputs, four analog BNC outputs
• Data storage: > 200 days
• Communications: Ethernet 100/10 Mbps, RS‑232 serial
• Power: 90–264 V AC, 47–63 Hz or 12 V DC; consumption 45 W
• Dimensions: 18 cm H x 48 cm W x 61 cm D (7" H x 19" W x 24" D); rack mountable
• Weight: 18 kg (40 lb)
• Operating conditions: 0 – 40°C; RH 0 – 90% non‑condensing
• Computer requirements for software: Windows XP/Vista/7; minimum 1 GB RAM