Nephelometer Introduction & Operation. What is a Nephelometer? The Nephelometer is an analytical instrument used to measure the light-scattering coefficient.

NephelometerNephelometerIntroduction & Operation

What is a Nephelometer?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.

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.

3 Types of Dust3 Types of Dust

• Heavy Dust - The layer of dust on furniture and floors.• Settling Dust - Particulate’s 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.

Airborne ParticulateAirborne Particulate

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

The Human Airway SystemThe Human Airway System

Met One Instruments Proprietary

AlveolarRegion

AlveolarRegion

Trachea-Bronchial Region

Trachea-Bronchial Region

Head AirwaysRegion

Head AirwaysRegion

Design IntentionDesign Intention

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

AlveolarAlveolar

Trachea-BronchialTrachea-Bronchial

GizNeph EngineGizNeph Engine

Met One Instruments Proprietary

Theory of OperationTheory of Operation

Why Sheath Air is ImportantWhy Sheath Air is Important

• Prevents Engine Contamination.• Improves Response Time.

Fig. 1 Fig. 2W/OUT SHEATH AIR W/ SHEATH AIR

Handheld NephelometerHandheld Nephelometer

Protective Inlet

Flow Adjust

Charging Jack

Iso-kinetic Inlet

Select/Mode

ON/OFF / Sample

Zero Cap

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.

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.

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

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.

USB Port

Filter Port

Filter ReplacementFilter 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.

ReliabilityReliability

COMPONENT NORMAL USAGE CONTINUOUS USAGE

ELECTRONICS >10 YEARS >5 YEARS

FIRMWARE / SOFTWARE FIELD UPGRADABLE FIELD UPGRADABLE

BATTERY >3 YEARS >1 YEAR

PUMP >3 YEARS >1 YEAR

CONTAMINATION VARIABLE VARIABLE

AMBIENT LIGHT VARIABLE VARIABLE

ZERO STABILITY VARIABLE VARIABLE

LASER DIODE >10 YEARS >5 YEARS

BenefitsBenefits

• 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

Common ApplicationsCommon 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

Thank You