Air Quality & Particle Counters

Air quality meters for indoor environmental checks — CO, CO₂, O₂, temperature/humidity, and particulate instruments used by HVAC, facility, and IAQ survey teams. Products below are live REED SKUs on this site.

Common tools on this site

• Multi-gas / IAQ meters — REED R9905 and R9920 air quality meters; R9910SD data logging air quality meter for documented multi-point surveys.
• Particle counter — REED R9930 air particle counter with R9930-FILTER, R9930-ADP power adapter, and R9930-7.4V replacement battery when OEM pairing is clear.
• Replacement probes (R9910SD family) — R9910SD-CO (CO), R9910SD-CO2 (carbon dioxide), R9910SD-O2 (oxygen), and R9910SD-TH (temp/humidity) for R9910SD and SD-9901 when stocked.
• R9905 probe — R9905-PROBE replacement temperature and humidity probe for the R9905.

What to measure

• Carbon monoxide (CO) — combustion appliance and safety checks.
• Carbon dioxide (CO₂) — ventilation and occupancy indicators.
• Oxygen (O₂) — confined-space and process checks when the OEM probe is listed.
• Particles — cleanroom / HVAC particulate surveys with the R9930 when stocked.
• Temp / humidity — ambient RH alongside IAQ gases.

Selection tips

• Match sensors and ranges to the contaminants you care about.
• Logging and alarms help when documenting multiple rooms or shifts.
• Calibrate or bump-check gas sensors per the manufacturer’s schedule; keep spare probes and filters when the OEM offers them.
• Pair with environmental meters when you need ambient RH alongside IAQ gases.

Models in this category

Indoor air quality meters

• REED R9905 Data Logging Indoor Air Quality Meter: triple LCD display simultaneously monitors carbon dioxide (CO2), temperature and relative humidity.
• REED R9910SD Data Logging Air Quality Meter: measures oxygen (O2), carbon dioxide (CO2), carbon monoxide (CO), temperature and humidity.
• REED R9920 Indoor Air Quality Meter: simultaneously monitors carbon dioxide (CO2), temperature and relative humidity.

Particle and dust meters

• REED R9930 Air Particle Counter: displays up to 6 particle sizes down to 0.3μm.

Accessories and replacement parts: REED R9905-PROBE Replacement Temperature And Humidity Probe For R9905, REED R9910SD-CO Replacement CO Probe For R9910SD & SD-9901, REED R9910SD-CO2 Replacement Carbon Dioxide Probe For R9910SD & SD-9901, REED R9910SD-O2 Replacement Oxygen Probe For R9910SD & SD-9901, REED R9910SD-TH Replacement Temp/Humidity Probe For R9910SD & SD-9901, REED R9930-7.4V Replacement Battery For R9930, REED R9930-ADP Replacement Power Adapter For R9930, REED R9930-FILTER Replacement Filter For R9930.

Calibration

Eligible meters can ship with ISO/IEC 17025 accredited calibration. Ask for the gases and ranges your procedure covers.

Frequently asked questions

Which meter should I use to check CO2 and ventilation?

Both of these meters use a nondispersive infrared (NDIR) CO2 sensor and also read temperature and relative humidity: - REED R9905: data logging indoor air quality meter; 0 to 5000 ppm at ±(75 ppm + 3% rdg.), extending to 30,000 ppm. - REED R9920: 0 to 9999 ppm at ±(5% rdg. + 75 ppm).

Which meter measures CO, CO2 and O2 together?

The REED R9910SD data logging air quality meter measures oxygen (O2), carbon dioxide (CO2), carbon monoxide (CO), temperature and humidity. REED lists replacement probes for each: R9910SD-CO, R9910SD-CO2, R9910SD-O2 and R9910SD-TH.

How small a particle can the R9930 count?

The REED R9930 Air Particle Counter displays up to 6 particle sizes, down to 0.3 μm.

Can I replace the probe on the R9905?

Yes. The R9905-PROBE is REED's replacement temperature and humidity probe for the R9905.