Direct-reading air quality instruments or monitors provide information at the time of sampling, enabling rapid decision-making. These instruments provide the trained and experienced user the capability to determine if site personnel are exposed to airborne concentrations which exceed instantaneous exposure limits for specific hazardous air contaminants. Air quality monitors can be useful in identifying oxygen-deficient or oxygen-enriched atmospheres, immediately dangerous to life or health conditions, elevated levels of airborne contaminants, flammable atmospheres, and radioactive hazards. Direct reading instruments are particularly useful for identifying point source contamination or emissions such as gas leaks. Periodic monitoring of airborne levels with a real-time monitor is often critical, especially before and during work activities. Direct-reading instruments are useful for performing screening surveys to determine areas where additional evaluation is warranted.
Photoionization Detectors (PIDs) |
PIDs use a fan or a pump to draw air into the instrument's detector. A high energy ultraviolet (UV) light source ionize the chemicals in the airstream. The charged molecules are collected on a charged surface, which generates a current that is directly proportional to the concentration of the chemical in the air being sampled. The ionization potential (IP) describes the amount of energy needed to induce ionization in a particular chemical.
PIDs are used for:
- Site characterization
- Exposure monitoring
- Soil and water sample screening
- Soil gas monitoring
Single Gas Monitors and Tubes |
Single or dual gas monitors are available from Geotech which can monitor carbon dioxide, carbon monoxide, hydrogen sulfide, and a variety of additional toxic gases. The sample concentration is displayed in ppm, percent oxygen or percent LEL (Lower Explosive Limit), as applicable.
Multi-gas Hand-held Monitors |
Multi-gas monitors incorporate separate sensors for oxygen, combustible atmosphere, and up to three toxic gases in the same handheld monitor.
These monitors may operate in passive (diffusive) mode, or in active mode, in which a pump module draws air across the sensors.
Many flammable gas sensors do not provide reliable readings in an oxygen deficient atmosphere. Therefore, oxygen content must always be determined before taking combustible gas readings. Flammable gases and vapors are tested second for fire or explosion risk. Monitoring for toxicity is conducted last. This monitoring process is greatly simplified by using a multi-gas monitor containing sensors for oxygen, LEL, and the relevant toxic gases.
FID (Flame Ionization Detection) |
These units use a flame to ionize airborne contaminants. Once they are ionized, they can be detected and measured.
FIDs are the most sensitive for saturated hydrocarbons (alkanes), unsaturated hydrocarbons (alkenes and alkynes), and aromatic hydrocarbons.
Particulate Monitors |
Aerosol photometers operate by detecting scattered light. The amount of light reaching the detector is proportional to the number of particles passing through the detection chamber. Also known as nephelometers, these instruments are used to monitor particulate matter such as dusts, smokes, mists, and fumes. They can be used for monitoring the respirable fraction of dust, and are small enough to use for personal exposure monitoring. Results are reported in μg/m3 or mg/m3.
Air Velocity & Indoor Air Quality Meters |
Velocity meters (hotwire anemometers) are handheld devices with an extendable wand probe used to measure air speed (velocity). They can be used to monitor the effectiveness of ventilation systems and local exhaust systems.
Calibration Tools, Gases and Accessories |
A complete line of gas meter accessories for your air quality instruments.
- RAE Calibration Stations
- Rechargeable and Replacement Batteries
- Automotive Adapter Cable
- Tedlar® and ALTEF Gas Sampling Bags
- Charcoal⁄Watertrap Filters
- Maintenance Kits
- Calibration Gases
- Gas Flow Controllers
- UV Discharge Lamps for Photoionization Detectors
- Replaceable Toxic Gas and Combustible Gas Sensors
- Hard-sided Waterproof Case
Mercury Vapor Analyzer |
Ion Science MVI (Mercury Vapor Indicator)
The world's ONLY mercury vapor surveyor, the popular hand-held Mercury Vapor Indicator is established as a firm favorite with a world-wide following.
You do not need to know where mercury is before measuring, the MVI finds the contamination and measures it quickly and accurately. The high performance pump lets you know immediately when tiny levels of mercury vapor are present.
- Large Digital Display
- Continuous Readings
- "One-Hand" Operation
- Audible Alarm Warns of High Mercury Level
- High Performance Pump – For fast indication and recovery
- PTFE Probe with Moisture Trap Filter
- Highly Accurate Measurement – Other monitors may only be accurate to plus or minus 20%!
- Very Fast – Almost instantaneous reaction to mercury, other monitors may require up to 1 minute to get a reading!
- Not Just a "Spot" Checker – MVI gives continuous readings
- No need to regenerate between readings
Call 1.800.833.7958
Ion Science MVI Specifications
Ion Science MVI User Manual