ARA Instruments N-FRM Sampler


ARA Instruments N-FRM Sampler


A portable, rapidly deployable, battery-powered sampling and monitoring device for measuring sampling parameters, meteorological data and particulate counts

  • Versatile inlet configurations for PM₂.₅, PM₁₀, or TSP sampling
  • FRM quality 24-hour sampling at 16.7 LPM
  • Cost effective at a fraction of traditional site-based FRM samplers
  • Defensible data logging capabilities for all sampling parameters
  • Deployable compact size and battery power allows for remote use
  • Flexible mounting options for rapid deployment

It delivers Federal Reference Method (FRM) level of performance and integrates many additional functions for unmatched versatility.

The compact-sized sampler collects 24-hour TSP, PM₁₀, or PM₂.₅ filter samples and can simultaneously measure local meteorological parameters. It can also be equipped with a light scattering particle sensor to log temporal particulate variations. For added versatility, the N-FRM can be operated in directional sampling mode and also has the capability of remote turn on. For more utility, the N-FRM can be operated in sensor only mode for long term collection of meteorological and particulate data.

How it works

The N-FRM Sampler is specifically designed to meet the US-EPA operational specifications for PM10 and PM2.5 air sampling. To meet the EPA specifications, the N-FRM Sampler is designed to operate at 16.7 LPM and collect 24-hour samples to compare to EPA National Ambient Air Quality Standards. The ARA N-FRM Sampler is a microprocessor-controlled portable air sampler, which can be operated manually or programmed to collect scheduled samples. As specified by the EPA, all critical air sampling parameters are continuously monitored and logged as time indexed 5-min averages to validate the sample. These parameters include: flow rate, temperature, barometric pressure, and accumulated volume. Other sampler related performance parameters are also logged.

If the N-FRM Sampler is equipped with the Real-Time Particulate (RTP) Profiler and meteorological sensors, then PM10, PM2.5, wind speed, and wind direction are also included in the data record. The N-FRM sampler can be easily deployed. It can be mounted on a variety of structures using our universal mounting bracket that can be screwed, clamped, or attached to utility poles, trees, fence posts, etc. Another option is to use a freestanding tripod.

The N-FRM Sampler is equipped to operate from either AC or DC power sources. In the DC mode, the sampler operates from an internal battery pack. A charged battery pack is capable of operating the sampler for about 30-40 hours. This robust capacity allows the sampler to be used in cold weather and high altitude applications. A charger is supplied so the batteries can be re-charged in approximately one hour. 

Particulate Matter Sampling

The N-FRM Sampler can be set up for TSP, PM₂.₅, or PM₁₀, particulate sampling by configuring the sampling inlet components prior to the filter medium. To measure TSP, the omnidirectional Louvered Inlet is all that is required. For PM₁₀ sampling, an FRM style inertial separator (PM10 Impactor) is added. To collect PM₂.₅, the sharp-cut ARA VIS-A Cyclone is attached, which physically selects particles 2.5 microns and below.

Common N-FRM inlet configurations are shown in FIG. 1. The N-FRM inertial separators (PM10 Impactor) are designed to operate at a nominal sampling rate of 1 cubic meter per hour (16.7 liters per minute). The N-FRM Sampler incorporates a microprocessor-based active flow control to maintain the sampling rate as ambient conditions and filter loading changes. The sampling rate is monitored and adjusted several times a second and logged at 5-min intervals along with all other important sampling parameters.

Applications for the ARA N-FRM Sampler

  • Urban Air Monitoring Networks
  • National Air Monitoring Networks 
  • Roadside Air Monitoring
  • Industrial Perimeter Monitoring 
  • Environmental Impact Assessments
  • Research Projects 
  • Short-Term Hot Spot & Emergency Monitoring Industrial Hygiene


  •  Real-Time Particle Sensor (RTP) option for PM₂.₅ and PM₁₀
  • Directional sampling capability with meteorological sensor
  • Sensor-only mode enables long-term meteorological & dust surveys
  • Easy data retrieval via USB flash drive
  • Programmable with intuitive user interface
  • Low maintenance particulate separators require no grease or oil
  • Rechargeable batteries complete full charge in 1 hour
  • Uses standard FRM 47mm filter media and cassette


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