Nephelometer

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Nephelometer

• Introduction Operation

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What is a Nephelometer?

• The Nephelometer is an analytical instrument used
  to measure the light-scattering coefficient of
  atmospheric and indoor aerosols. It measures the
  particulates in the air.
• The main uses of Nephelometers relate to air
  quality measurement for pollution monitoring,
  climate monitoring and visibility.  
• A nephelometer has different levels of
  sensitivity depending on the design.

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Why the Strange Name?

• The term nephelometer is derived from the Greek
  word nephos, meaning cloud.
• The first nephelometers were developed about 100
  years ago to measure the turbidity level
  (cloudiness) of water samples.
• The first application for dust in air came along
  about 50 years ago. The first dust nephelometer
  used a Jeep headlight as a light source. Today,
  we use a small laser.

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3 Types of Dust

• Heavy Dust - The layer of dust on furniture and
  floors.
• Settling Dust - Particulates in the air floating
  around before it turns into heavy dust.
• Suspended Atmospheric Dust - Minute particles
  slowly settling or suspended by slight currents
  and existing in varying amounts in all air.

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Airborne Particulate

• Airborne particles are commonly either biological
  contaminants, particulate contaminants, gaseous
  contaminants or dust.

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The Human Airway System
Head Airways Region
Trachea-Bronchial Region
Alveolar Region
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Design Intention

• Our Nephelometers Are Designed such that Their
  Response Has Strong Overlap with Human Alveolar
  and Trachea-Bronchial Deposition

GizNeph Engine
Trachea-Bronchial
Alveolar
Met One Instruments Proprietary
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Theory of Operation
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Why Sheath Air is Important

• Prevents Engine Contamination.
• Improves Response Time.

Fig. 1
Fig. 2 W/OUT SHEATH
AIR W/ SHEATH
AIR
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Handheld Nephelometer
Protective Inlet
Iso-kinetic Inlet
Flow Adjust
Charging Jack
Select/Mode
ON/OFF / Sample
Zero Cap
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Operation

• Be sure the inlet is open
• Depress the Start/Stop Key for a few seconds to
  power up the unit.
• The display will show the units (µg/M3), the
  sample mode (Manual) and the selected K Factor
  (Arizona Road Dust)
• Use the select key to change settings.
• Use the Start/Stop key to start a sample.

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K Factors

• The K factor corrects the reading to a certain
  type of dust
• The unit comes with 3 K-factors already in the
  library.
• These are Arizona Road Dust (ARD), Limestone and
  Coal Fly Ash.
• Other K factors may be determined through
  side-by-side sampling with a gravimetric sampler.

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Sampling Mode

• There are three sampling modes
• The Manual Mode takes a one minute sample and
  shuts off automatically
• The STEL Mode takes a 15 minute sample and shuts
  off automatically
• The Continuous Mode runs until you shut it off

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Datalog PC Interface

• The data from the Nephelometer may be downloaded
  to a PC
• The software is included with each unit sold
• It allows storage of data, the addition of new K
  factors to the library, and the setting of the
  functions like the clock
• You can also export data as a .csv file, which
  can be converted to Excel.

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Filter Replacement

• The Dust Monitor has a 0.2 micron filter to
  produce the clean air for the sheath system.
  This filter will normally need to be changed on
  an annual basis but may require a more frequent
  change if used in extremely dirty environments.

USB Port
Filter Port
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Reliability
COMPONENT NORMAL USAGE CONTINUOUS USAGE
ELECTRONICS gt10 YEARS gt5 YEARS
FIRMWARE / SOFTWARE FIELD UPGRADABLE FIELD UPGRADABLE
BATTERY gt3 YEARS gt1 YEAR
PUMP gt3 YEARS gt1 YEAR
CONTAMINATION VARIABLE VARIABLE
AMBIENT LIGHT VARIABLE VARIABLE
ZERO STABILITY VARIABLE VARIABLE
LASER DIODE gt10 YEARS gt5 YEARS
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Benefits

• Portable light weight unit
• Easy Operation
• Instant Readings
• Highly Sensitive
• Competitively Priced
• Monitoring Software Included

• Low Cost of Ownership
• Long Life Pump
• Automatic Power Save
• Selectable Sample Modes
• Sheath Air w/ user replaceable filter

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Common Applications

• Indoor Air Quality Investigation
• Industrial Hygiene Quality Control
• Occupational Health Control
• Walk Through Surveys
• Particulate Matter Study
• Workplace Plant Monitoring
• Evaluating Dust Generation / Suppression
• Emissions Monitoring
• HazMat Investigations

• Emergency Response
• Site Boundary Monitoring Environmental
  Measurement
• Industrial Process Monitoring
• Testing Air Filtration Efficiency
• Aerosol Research Studies
• Personal Exposure Monitoring
• Remediation Personal Surveillance
• Outdoor Environmental Monitoring
• Baseline Trending Screening

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Thank You