Particle Size Analysis in Estimating the Significance of Airborne Contamination

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TECHNICAL REPORTS SERIES No. 1 79
Particle Size Analysis
in Estimating the Significance
of Airborne Contamination
INTERNATIONAL ATOMIC ENERGY AGENCY, VIENNA, 1978

PARTICLE SIZE ANALYSIS
IN ESTIMATING THE SIGNIFICANCE
OF AIRBORNE CONTAMINATION
The following States are Members of the International Atomic Energy Agency:
AFGHANISTAN HOLY SEE PHILIPPINES
ALBANIA HUNGARY POLAND
ALGERIA ICELAND PORTUGAL
ARGENTINA INDIA QATAR
AUSTRALIA INDONESIA ROMANIA
AUSTRIA IRAN SAUDI ARABIA
BANGLADESH IRAQ SENEGAL
BELGIUM IRELAND SIERRA LEONE
BOLIVIA ISRAEL SINGAPORE
BRAZIL ITALY SOUTH AFRICA
BULGARIA IVORY COAST SPAIN
BURMA JAMAICA SRI LANKA
BYELORUSSIAN SOVIET JAPAN SUDAN
SOCIALIST REPUBLIC JORDAN SWEDEN
CANADA " KENYA SWITZERLAND
CHILE KOREA, REPUBLIC OF SYRIAN ARAB REPUBLIC
COLOMBIA KUWAIT THAILAND
COSTA RICA LEBANON TUNISIA
CUBA LIBERIA TURKEY
CYPRUS LIBYAN ARAB JAMAHIRIYA UGANDA
CZECHOSLOVAKIA LIECHTENSTEIN UKRAINIAN SOVIET SOCIALIST
DEMOCRATIC KAMPUCHEA LUXEMBOURG REPUBLIC
DEMOCRATIC PEOPLE'S MADAGASCAR UNION OF SOVIET SOCIALIST
REPUBLIC OF KOREA MALAYSIA REPUBLICS
DENMARK MALI UNITED ARAB EMIRATES
DOMINICAN REPUBLIC MAURITIUS UNITED KINGDOM OF GREAT
ECUADOR MEXICO BRITAIN AND NORTHERN
EGYPT MONACO IRELAND
EL SALVADOR MONGOLIA UNITED REPUBLIC OF
ETHIOPIA MOROCCO CAMEROON
FINLAND NETHERLANDS UNITED REPUBLIC OF
FRANCE NEW ZEALAND TANZANIA
GABON NICARAGUA UNITED STATES OF AMERICA
GERMAN DEMOCRATIC REPUBLIC NIGER URUGUAY
GERMANY, FEDERAL REPUBLIC OF NIGERIA VENEZUELA
GHANA NORWAY VIET NAM
GREECE PAKISTAN YUGOSLAVIA
GUATEMALA PANAMA ZAIRE
HAITI PARAGUAY ZAMBIA
PERU
The Agency's Statute was approved on 23 October 1956 by the Conference on the Statute of the IAEA
held at United Nations Headquarters, New York; it entered into force on 29 July 1957. The Headquarters of
the Agency are situated in Vienna. Its principal objective is "to accelerate and enlarge the contribution of
atomic energy to peace, health and prosperity throughout the world".
<Q IAEA, 1978
Permission to reproduce or translate the information contained in this publication may be obtained by
writing to the International Atomic Energy Agency, KSrntner Ring 11, P.O. Box 590, A-1011 Vienna, Austria.
Printed by the IAEA in Austria
January 1978
5 3 0 4 4
TECHNICAL REPORTS SERIES No. 179
PARTICLE SIZE ANALYSIS
IN ESTIMATING THE SIGNIFICANCE
OF AIRBORNE CONTAMINATION
INTERNATIONAL ATOMIC ENERGY AGENCY
VIENNA,! 978
PARTICLE SIZE ANALYSIS IN ESTIMATING THE
SIGNIFICANCE OF AIRBORNE CONTAMINATION
IAEA, VIENNA, 1978
STI/DOC/lO/179
ISBN 92-0-125078-9
FOREWORD
A better understanding of the exposure pathways leading to internal irradia-
tion is needed. Assessing the hazards is a complicated task which involves both
biological and physical considerations. Aerosols play the most important role in
the transport of radioactivity to man. They can enter the human body by a
direct pathway through inhalation or by indirect pathways through deposition in
the food chain. Their toxicity depends not only on their physical and chemical
properties but also on their aerodynamic characteristics. One of the most impor-
tant aerosol properties governing aerodynamic characteristics is the particle size
distribution.
In this report information on pertinent methods and techniques for analys-
ing particle size distributions is compiled. It is hoped that the publication will
make for the more reliable evaluation, assessment and control of the potential
hazards of suspended particulate matter.
A detailed outline of the work was prepared by a panel of experts. Certain
members of the group then worked on specific chapters. The Agency is parti-
cularly indebted to Mr. T.T. Mercer of the United States of America for writing
Chapters 2, 3, 4, 9 and 10, to Mr. O. Preining of Austria for writing Chapters 5,
6 and 7, and to Mr. J. Sisefsky of Sweden for writing Chapter 8. The many
detailed comments on the resulting draft that were then received from the ori-
ginal panel members were studied by the Chairman, Mr. Mercer, and the Vice-
Chairman, Mr. Preining, who together prepared the final version of the report.
The Agency's officer responsible for co-ordinating the work was F.N. Flakus
from the Radiological Safety Section of the Division of Nuclear Safety and
Environmental Protection.

CONTENTS
CHAPTER 1. INTRODUCTION 1
CHAPTER 2. PARTICLE SIZE DISTRIBUTIONS 3
2.1. Definitions and descriptions 3
2.1.1. Populations
2.1.2. Random variables, probability density (relative frequency)
functions, and cumulative distribution functions
2.1.3. Sampling and sampling statistics
2.1.4. Distributions peculiar to particle size work
2.2. Number-size distributions 22
2.2.1. The log-normal distribution
2.2.2. The normal distribution
2.2.3. The power function distribution
2.2.4. The exponential distribution
2.3. Activity-size distributions 31
CHAPTER 3. METHODS OF LINEAR SIZE ANALYSIS 33
3.1. Collection of samples for linear size analysis 33
3.1.1. Thermal precipitation
3.1.2. Electrostatic precipitation
3.1.3. Filter methods
3.2. Definitions of linear particle size 56
3.2.1. Statistical geometric diameters
3.2.2. Non-statistical diameters
3.2.3. Particle morphology
3.3. Shape factors .'..! 59
3.3.1. Geometric shape factors relating measured diameters
to some geometric particulate property
3.3.2. Aerodynamic shape factors
CHAPTER 4. GRAVITATIONAL AND INERTIAL SEPARATION
OF PARTICLES 71
4.1. Some basic principles 71
4.1.1. Fluid resistance to relative particle motion
4.1.2. Motion of a particle subject to a constant force
4.2. Principles of instrument operation 74
4.2.1. Horizontal elutriation
4.2.2. Centrifugation
4.2.3. Impaction of particles from air impinging normally
on a plate
4.2.4. Equivalent size measured
4.3. Specific instrumentation : 81
4.3.1. Horizontal elutriators - cumulative type
4.3.2. Horizontal elutriators - discrete type
4.3.3. Aerosol centrifuges — cumulative type: the Goetz
"aerosol spectrometer"
4.3.4. Aerosol centrifuges - discrete type: conifuges
4.3.5. Multi-stage devices; impaction and cyclone devices
4.3.5.1. Rectangular jet impactors
4.3.5.2. Round jet impactors
4.3.5.3. The multicyclone
4.3.5.4. Treatment of data for multi-stage impactors
and cyclones
4.3.6. Single-stage impactor — discrete type
CHAPTER 5. ELECTROSTATIC SIZING DEVICES 129
5.1. Principles of operation 129
5.1.1. Cumulative sampling
5.1.2. Discrete sampling
5.2. Types of data and "size" measured 130
5.3. Specific instruments 132
'5.3.1. The Model 3000 Whitby aerosol analyser
5.3.2. The.Megaw-Wells parallel-plate instrument
5.3.3. The Mohnen-Stierstadt cylindrical instrument
5.4. Evaluation 138