ENVIRONMENTAL PROTECTION AGENCY APTI 435: Atmospheric Sampling Course Student Manual
Table of Contents Chapter 1: An Introduction to Atmospheric Sampling... 1-1 1.1 Introduction... 1-2 1.2 Sampling Train Design... 1-2 References... 1-5 Chapter 2: Basic Gas Properties and Mathematical Manipulations... 2-1 2.1 Temperature... 2-1 The Fahrenheit and Celsius Scales... 2-1 Absolute Temperature... 2-1 2.2 Pressure... 2-3 Definition of Pressure... 2-3 Barometric Pressure... 2-3 Torricelli Barometer... 2-4 Fortin Barometer... 2-4 Aneroid Barometer... 2-7 Pressure Transducers... 2-8 Gauge Pressure... 2-10 Absolute Pressure... 2-10 The Concept of Pressure-Head... 2-12 Dalton s Law of Partial Pressure... 2-12 2.3 The Ideal Gas Laws... 2-13 Boyle s Law... 2-13 Charles Law... 2-13 The Law for Ideal Gases... 2-13 Molar Volume... 2-14 2.4 Gas Density... 2-15 Standard Conditions for Atmospheric Sampling... 2-16 Origin and Definition of Viscosity... 2-16 Kinematic Viscosity... 2-17 Liquid Viscosity versus Gas Viscosity... 2-18 2.5 Reynolds Number... 2-20 2.6 Summary of Useful Equations... 2-22 Temperature... 2-22 i
Pressure... 2-22 Ideal Gas Law... 2-23 Gas Density... 2-23 Viscosity, µ... 2-23 Reynolds Number... 2-23 2.7 Units of Measurements... 2-24 Recommended Units... 2-24 Conversion Problems... 2-26 References... 2-29 Chapter 3: Air Measuring Instruments... 3-1 3.1 Introduction to Air Movers... 3-1 Relationship of Air Movers to Other Sampling System Components... 3-1 Air Mover Classification... 3-2 3.2 Air Mover Selection Criteria... 3-2 Pollutant Concentration and Sampling Time... 3-2 Sampling Rate Required... 3-3 Physical and Chemical Nature of Air to be Sampled... 3-3 Portability of Air Mover... 3-3 Air Mover Noise... 3-3 Air Mover Maintenance... 3-4 Resistance... 3-4 Constant Flow Rate... 3-4 3.3 Pumps... 3-5 Definition and Classification... 3-5 Positive Displacement Pumps... 3-5 Centrifugal Pumps... 3-7 Driving Forces for Pumps... 3-9 Characterisitic Curves... 3-9 Selecting a Pump... 3-10 Pump Gauges... 3-11 3.4 Ejectors... 3-12 Principle of Operation... 3-12 Driving Forces... 3-13 Sampling Use of Ejectors... 3-13 3.5 Liquid Displacers... 3-13 Principle of Operation... 3-13 Sampling by Use of Liquid Displacement... 3-14 3.6 Air Displacers... 3-14 ii
Evacuated Flasks: Principle of Operation... 3-14 Sampling by Use of Evacuated Flasks... 3-15 Plastic Bags: Principle of Operation... 3-14 Sampling by Use of Plastic Bags... 3-15 3.7 Flow Rate Control... 3-15 Control by Diversion... 3-15 Resistance Control... 3-16 Driving Force Control... 3-16 3.8 Flow Rate for Sampling... 3-16 Need for Control... 3-16 Control Mechanisms... 3-17 3.9 Air Measuring Instruments... 3-18 Introduction... 3-18 Types of Air Measuring Devices... 3-18 Calibration... 3-19 3.10 Volume Meters... 3-20 The Spirometer (or Bell Prover ) Primary Standard... 3-20 Displacement Bottle Technique Primary Standard... 3-22 Frictionless Pistons Primary Standard... 3-23 Automated Bubble Flowmeters... 3-27 Automated Dry-Piston Flowmeters... 3-28 Wet Test Meter (WTM) Secondary Standard... 3-28 Roots Meter Secondary Standard... 3-31 Dry Test Meter Secondary Standard... 3-33 3.11 Rate Meters... 3-35 Variable-Pressure Meters Head Meters... 3-35 Variable Area Meters... 3-38 Mass Flow Meters Heat Transfer Meters Hot-Wire Meters 3-40 3.12 Velocity Meters... 3-41 Pitot Tube Primary Velocity Standard... 3-42 Standard Pitot Tube Secondary Velocity Standard... 3-43 S-Type Pitot Tube Secondary Velocity Standard... 3-45 Thermal Anemometer Secondary Velocity Standard... 3-46 3.13 Sample Problems... 3-47 Problem 1: Volume Conversion to Standard Conditions... 3-47 Problem 2: Orifice Conversion When Used at Other Calibration Conditions... 3-47 Problem 3: Conversion for Different Gas Used with a Rotameter... 3-48 Problem 4: Pump Capacity... 3-49 iii
3.14 Additional PM 2.5 Flowmeters and Devices... 3-50 Bubble Flowmeters... 3-50 Piston Flowmeters... 3-50 Mass Flowmeters... 3-50 Orifice Devices... 3-50 Laminar Flow Elements... 3-51 Wet Test Meters... 3-51 Dry Gas Meters... 3-51 References... 3-52 Chapter 4: Particulate Matter Sampling... 4-1 4.1 Introduction... 4-1 Principles of Inertial Collection... 4-5 4.2 Inertial Sampling Devices... 4-6 Impaction Devices... 4-6 Impingement Devices... 4-14 Centrifugal Separation Devices... 4-14 Virtual Impactors Dichotomous Sampler... 4-16 4.3 Collection Efficiency and Penetration Efficiency of Inertial Sampling Devices... 4-21 Definition of Collection Efficiency and Penetration Efficiency 4-21 Impactor Performance Characteristics... 4-22 Properties of Aerosols Affecting Inertial Collection Efficiency... 4-22 Properties of the Collecting Device Influencing Collection Efficiency... 4-23 4.4 Limitations and Sources of Error in Inertial Collection 4-24 Inherent Errors in Sample Collection... 4-24 Errors Associated with the Calibration of Collection Devices... 4-25 Errors in Sample Analysis... 4-25 Size-Selective Inlets and Devices for Aerosol Sampling... 4-25 4.5 Filtration Sampling... 4-32 Introduction... 4-32 General Considerations... 4-32 The Theory of Filtration... 4-33 Collection Efficiency of Filters... 4-34 Characteristics of Filter Media... 4-38 Sample Problems... 4-54 4.6 Gravitational Sampling... 4-55 Dustfall Bucket or Jar... 4-55 Precipitation Collectors... 4-55 iv
4.7 Electrostatic Precipitators... 4-56 Introduction... 4-56 Principles of Electrostatic Precipitation... 4-56 Collection Efficiency... 4-57 Specific Applications... 4-57 4.8 Thermal Precipitators... 4-58 Introduction... 4-58 Collection Efficiency and Depostion Pattern... 4-58 Advantages and Disadvantages of Thermal Precipitators... 4-59 4.9 Summary... 4-59 References... 4-60 Chapter 5: Methodologies and Instrumentation for Particulate Matter Sampling... 5-1 5.1 Introduction... 5-1 5.2 High-Volume Sampling for Suspended Particulate Matter (SPM) and Air Toxics... 5-1 5.3 High-Volume Air Sampling... 5-3 Introduction... 5-3 Development of the High-Volume Sampler... 5-3 Sampler-Shelter Combination... 5-5 Filter Media for High-Volume Sampler... 5-6 Precautions in Filter Handling... 5-8 Calibration... 5-10 U.S. EPA High-Volume Sampling Procedure for TSP... 5-18 Sample Problems... 5-22 Analysis of High-Volume Filters... 5-24 Sampling Accuracy and Precision... 5-25 Accuracy... 5-25 Precision... 5-30 Maintenance... 5-30 Summary... 5-32 5.4 FRM for the Determination of Particulate Matter as PM 10... 5-32 Applicability... 5-32 Principle... 5-32 Range... 5-34 Precision... 5-34 Accuracy... 5-35 Potential Sources of Error... 5-36 v
PM 10 Sampler Apparatus... 5-37 Filter Media... 5-38 Calculations... 5-38 Sample Problems... 5-39 5.5 FRM and FEM for the Determination of Fine Particulate Matter as PM 2.5... 5-41 Reference Methods for PM 2.5 (FRM)... 5-41 Designated Methods for PM 2.5... 5-45 Equivalent Methods for PM 2.5 (FEM)... 5-46 Limitations of PM 2.5 Reference and Class I Equivalent Methods5-47 Approved Regional Methods (ARMs)... 5-48 Calculations... 5-48 Sample Problems... 5-48 5.6 FRM and FEM for the Determination of Coarse Particles (PM 10 -PM 2.5 )... 5-50 5.7 PM 2.5 Speciation Sampling... 5-51 5.8 Continuous in situ Monitoring for Particulate Matter.. 5-55 National Core (NCore)... 5-56 State and Local Air Monitoring Stations (SLAMS)... 5-56 5.9 Automated Federal Equivalent Monitors... 5-56 Beta Attenuation Monitor (BAM)... 5-57 Tapering Element Oscillating Microbalance (TEOM )... 5-58 5.10 Other Automated PM Methods... 5-59 Mass and Mass Equivalent... 5-60 Visible Light Scattering... 5-61 Visible Light Absorption... 5-64 Electrical Mobility... 5-66 Multi-Elemental Analyzer... 5-69 References... 5-74 Chapter 6: Gaseous Sampling... 6-1 6.1 Principles of Absorption... 6-1 Introduction... 6-1 Types of Absorption... 6-1 Physical Absorption... 6-2 Chemical Absorption... 6-2 6.2 Collection Efficiency... 6-3 Factors Affecting Collection Efficiency... 6-3 Absorber Characteristics... 6-3 Chemical Characteristics... 6-4 vi
Physical Characteristics... 6-5 6.3 Determination of Collection Efficiency... 6-5 Absorption Devices... 6-5 Fritted-Glass Absorbers... 6-6 Impingers... 6-9 Summary... 6-10 Current Applications of Absorption in Atmospheric Sampling... 6-10 6.4 Principles of Adsorption... 6-10 Basic Principles... 6-10 Types of Adsorption... 6-11 Variables Affecting Gas Adsorption... 6-12 Adsorption Isotherms... 6-13 Adsorbate Characteristics... 6-14 Adsorbent Characteristics... 6-16 Typical Adsorbents... 6-17 Adsorption Losses in Air Sampling... 6-19 Current Applications of Adsorption in Atmospheric Sampling... 6-19 Summary... 6-22 6.5 Selection and Performance of Wet Collector Media.. 6-23 Introduction... 6-23 Solubility of Pollutant... 6-23 Rate of Reaction... 6-25 Collection Efficiency... 6-25 Retention Characteristics of Absorbent (Solvent)... 6-26 Retention of Gases and Vapor by Chemical Reaction... 6-28 Retention of Particulate Matter... 6-29 6.6 Principles of Grab Sampling... 6-29 Introduction... 6-29 Evacuated Containers... 6-29 Air Displacement or Purging... 6-33 Liquid Displacement... 6-34 Inflation Plastic Bag Sampling... 6-34 Syringes... 6-36 Grab Sampling Techniques... 6-36 Current Applications of Whole Air (Grab and Integrated) Sampling in Ambient Air... 6-36 6.7 Principles of Cryogenic (Freezeout) Sampling... 6-36 Introduction... 6-36 Concept... 6-37 Equipment... 6-37 vii
Single-Stage Units... 6-38 Multistage Units... 6-38 Efficiency... 6-40 Current Applications of Cryogenic (Freezeout) Sampling in Ambient Air... 6-41 Summary... 6-42 References... 6-43 Chapter 7: Standard Methods for Criteria Pollutants... 7-1 7.1 Introduction... 7-1 7.2 Reference Method and Equivalent Method... 7-1 Criteria Pollutants and Measurement Methods... 7-2 Particulate Matter... 7-4 Ozone... 7-6 Carbon Monoxide... 7-7 Nitrogen Dioxide... 7-7 Sulfur Dioxide... 7-8 Lead... 7-10 References... 7-11 Chapter 8 : Introduction to Ambient Air Sampling for Air Toxics... 8-1 8.1 Introduction... 8-1 What are Toxic Air Pollutants?... 8-1 Clean Air Act of 1990... 8-2 Timeline for Air Toxics Monitoring... 8-3 8.2 What is Risk?... 8-5 What is a Risk Assessment?... 8-6 Hazard Identification... 8-7 Weight of Evidence for Health Problems of Concern... 8-7 Exposure Assessment... 8-8 Dose-Response Assessment... 8-8 Dose-Response Relationships... 8-9 Risk Characterization... 8-9 8.3 Introduction to Air Toxics Methods... 8-10 Monitoring Program Goal and Objectives... 8-10 Description of the Methods... 8-13 Compendium Method TO-11A... 8-14 viii
Compendium Method TO-13A... 8-16 Compendium Method TO-15A... 8-18 Compendium Method IO-3.5... 8-20 References... 8-23 Appendix A: Statistical Techniques Employed in Atmospheric Sampling...A-1 A.1 Introduction... A-1 A.2 The Data Quality Objective (DQO) Process... A-2 The Seven Steps of the DQO Process... A-2 Outputs of the DQO Process... A-3 A.3 Data Collection Design... A-3 Data Plotting... A-3 A.4 Graphical Analysis... A-4 Frequency Tables... A-4 The Frequency Polygon... A-6 The Histogram... A-6 The Cumulative Frequency Distribution... A-8 Distribution of Data... A-9 Transformation of Data... A-9 The Logarithmic Transformation... A-10 Probability Graph Paper... A-11 Least-Square Linear Regression... A-12 A.5 Measures of Central Tendency... A-14 Arithmetic Average, or Mean... A-14 Median... A-15 Geometric Mean... A-16 A.6 Measures of Dispersion... A-17 The Range... A-17 Standard Deviation... A-18 Coefficient of Variation... A-19 Standard Geometric Deviation... A-20 A.7 Distribution Curves... A-22 The Normal Distribution... A-22 Lognormal Distributions... A-24 References... A-26 Appendix B: Glossary and Acronyms...B-1 B.1 Glossary... B-1 ix
B.2 Acronyms... B-28 Appendix C: Conversion Factors and Useful Information... C-1 Appendix D: Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air, Second Edition... D-1 Appendix E: Compendium of Methods for the Determination of Inorganic Compounds in Ambient Air... E-1 Appendix F: Theory and Calibration Procedures for the Use of a Rotameter... F-1 F.1 Nomenclature... F-1 F.2 Description of a Rotameter... F-2 F.3 Development of Flow Equations... F-3 General Flow Rate Equations... F-3 Computation of Reynolds Number... F-5 F.4 Common Practices in the Use of a Rotameter for Gas Flow Measurement... F-6 Procedures for the Calibration of a Rotameter... F-7 A Universal Calibration Curve... F-8 Development of a Universal Calibration Curve... F-9 F.5 Use of the Universal Calibration Curve for a Rotameter... F-11 To Determine an Existing Flow Rate... F-11 To Establish a Required Sampling Rate... F-11 To Predict Calibration Curves... F-12 Appendix G: Significant Figures and Rounding Off... G-1 G.1 Working with Numbers Intro Problems... G-2 G.2 Approximate Numbers... G-2 Rule 1 (General)... G-3 Rule 2 (General)... G-3 x
G.3 Rounding Approximate Numbers... G-3 Rule for Rounding Approximate Numbers... G-3 G.4 Adding and Subtracting Approximate Numbers... G-4 Truncating Approximate Numbers Following Addition or Subtraction... G-4 G.5 Multiplying and Dividing Approximate Numbers... G-5 Significant Digits... G-5 Truncating Approximate Numbers Following Multiplication or Division... G-6 G.6 Reasonability... G-8 Rule to Meet the Conditions of Reasonability... G-8 G.7 Practice Exercises... G-9 G.8 Answers to Intro Problems... G-10 G.9 Answers to Practice Exercises... G-11 xi