Meetprincipes: NOx: Cross-Flow Modulation Chemiluminescence Detection Method SO2, CO: Cross-Flow Modulation Non-Dispersive Infrared Absorption Method CO2: Non-Dispersive Infrared Absorption Method O2: Galvanic, Zirconia or Paramagnetic Method Measuring ranges (standard model) NOx A-range 0-25/50/100/250/500/1000/2500ppm（standard spec.） B-range 0-50/100/250/500/1000/2500/5000ppm SO2: 0-200/500/1000ppm CO A-range 0-200/500/1000/2000/5000ppm （standard spec.） B-range 0-0.5/1/5/10/15 vol% （B-range is not available for PG-350） CO2: 0-5/10/20 vol% O2 0-5/10/25 vol%（Galvanic or Zirconia method) 0-10/25 vol%（Paramagnetic method）