CDC/NIOSH respiratory health and safety research needs carbon dioxide gas analyzers to support air quality evaluation in occupational environments, especially enclosed cab settings. The instruments must provide precise, stable, continuous CO2 monitoring from 0 to 10,000 ppm with research-grade sensitivity and a low detection limit. They must also offer multiple communication and output options for integration into laboratory and field research setups. The analyzers will be used to assess ventilation performance and support studies on worker exposure and respiratory health where CO2 monitoring can indicate poor air quality or inadequate ventilation.