1. Session 4: Air Pollution Measurements
CE AIR POLLUTION CONTROL Fall 2008
Session 4: Air Pollution Measurements
Fall 2008
By Wen-Whai Li
Air Pollution Effects

2. De Nevers Problems 4.7; 4.8; 4.15; 4.16;4.17 Reading Assignment:
H.W. #4: Due Sep. 24, 2008
De Nevers Problems 4.7; 4.8; 4.15; 4.16;4.17
Reading Assignment:
De Never: Chapter 4
U.S. EPA siting regulations (Appendices D and E to Part 58), p
Fall 2008
By Wen-Whai Li
Air Pollution Effects

3. Ambient Monitoring Measurements of Air Pollutants.
Time-integrated Air Monitoring
Particulate Matter
Hi-vol: 1 m3/min
Mid-vol: 100 l - 1 m3/min
Low-vol: 10 l l /min
Personal: < 10 l/min
Vapor
Grab samples
Canister
Media
Continuous Air Monitoring
Fall 2008
By Wen-Whai Li
Air Pollution Effects

4. Ambient Monitoring Meteorological Measurements. Surface Meteorology
Wind Direction
Wind Speed
Atmospheric Temperature
Atmospheric Humidity
Atmospheric Pressure
Vertical Temperature Profile
Upper Air Measurement
Balloon Measurements
Radiosonde:
Rawinsonde:
Rocket-fired Equipment falling through the atmosphere:
Remote Sensing:
Fall 2008
By Wen-Whai Li
Air Pollution Effects

5. Air Monitoring Objectives
Provide air pollution data to the general public in a timely manner
Support compliance with NAAQS and emission strategy development
Support for air pollution research studies
Fall 2008
By Wen-Whai Li
Air Pollution Effects

6. Types of Air Monitoring Sites
Highest concentration
Population-oriented community exposure
Source impacts
Background
Regional transport
Welfare impacts on visibility, vegetation, wild life, etc
Fall 2008
By Wen-Whai Li
Air Pollution Effects

7. Air Monitoring Design Stage of Air Monitoring
Pre-construction/remediation (Background) Monitoring
Post-construction/remediation Monitoring
Monitoring during Construction/remediation Activities
Pollutants to be Monitored
Criteria Pollutants
Non-criteria Pollutants
Monitoring Locations
Case I: Free from the impacts from other sources
Case II: Multisource emissions in flat terrain
Case III: Multisource emissions in complex terrain
Fall 2008
By Wen-Whai Li
Air Pollution Effects

8. Air Monitoring Design Duration Sampling Methods Sampling Locations
Sampling Plan
Sampling Media
Fall 2008
By Wen-Whai Li
Air Pollution Effects

9. Distance to PM Sampler
Fall 2008
By Wen-Whai Li
Air Pollution Effects

10. Distance to Other Samplers
Fall 2008
By Wen-Whai Li
Air Pollution Effects

11. Siting Summary
Fall 2008
By Wen-Whai Li
Air Pollution Effects

12. Isokinetic Sampling
When the sampling inlet axis is aligned parallel to the air stream and the air velocity entering the probe is the same as the free stream velocity approaching the inlet, the sampling procedure is called isokinetic sampling.
Fall 2008
By Wen-Whai Li
Air Pollution Effects

13. Anisokinetic Sampling
Fall 2008
By Wen-Whai Li
Air Pollution Effects

14. Anisokinetic Sampling: Superisokinetic
Fall 2008
By Wen-Whai Li
Air Pollution Effects

15. Anisokinetic Sampling: Subisokinetic
Fall 2008
By Wen-Whai Li
Air Pollution Effects

16. Dichotomous Air Monitors
Fall 2008
By Wen-Whai Li
Air Pollution Effects

17. Dichotomous Air Monitors
Fall 2008
By Wen-Whai Li
Air Pollution Effects

18. Principle of Operation
Operation Principle
Large particles with greater inertia cannot follow the sharp turn made by the air steam and continue to move in their initial directions and therefore are separated from the air stream.
Virtual Impaction
The air stream is forced to make a turn not by physical obstruction but by the reduction of flow velocity, a virtual impaction.
Aerodynamic Diameter
The behavior of a particle in the air stream is based on its aerodynamic properties rather than the physical size and shape.
Fall 2008
By Wen-Whai Li
Air Pollution Effects

19. Conceptual diagram of particle deposition mechanisms
Fall 2008
By Wen-Whai Li
Air Pollution Effects

20. Schematics of Dichotomous Air Monitor
PM10 inlet
Fall 2008
By Wen-Whai Li
Air Pollution Effects

21. Example for Dichotomous PM Measurements
Cc= 30 μg/m3
CF= 10 μg/m3 FT= 16.7l/min or 1m3/hr
t = 24 hrs
MF= CF · FF· t
= (10 μg/m3)· (0.9 m3/hr) · (24 hrs)
= 216 μg
MC= (CC · FT· t) + (CF · FC· t)
= (30 μg/m3)· (1.0 m3/hr) · (24 hrs) +
= (10 μg/m3)· (0.1 m3/hr) · (24 hrs)
= 720 μg + 24 μg
= 744 μg
Mc= 744 μg
MF= 216 μg
Fall 2008
By Wen-Whai Li
Air Pollution Effects

22. Derivation of the Concentration Equations
CF, CC FF FC
t = sampling time, hr
A= Actual mass to be collected, μg
M= mass collected on the filter, μg
F= flowrate, m3/hr
Subscript:
C: coarse particulate
F: fine particulate
T: total
Fall 2008
By Wen-Whai Li
Air Pollution Effects

23. Bioassay Implication PM2.5 Filter
The mass collected on the PM2.5 filter represents FF/FT of the actual ambient concentration. Under standard operating conditions, FF/FT is 0.9 (or 90 %). In other words, if the average ambient PM2.5 concentration is 10 μg/m3, the dose retained on the filter for bioassay analysis is equivalent to an ambient PM2.5 concentration of 9 μg/m3.
PM Filter
The mass collected on the PM filter represents the sum of actual coarse PM (PM10-2.5) plus a fraction of fine PM (PM2.5), an amount of (FT-FF)/FT collected during the sampling period. Under standard operating conditions, (FT-FF)/FT is 0.1 (or 10 %). In other words, if the average ambient PM concentration is 30 μg/m3 and PM2.5 concentration is 10 μg/m3, the dose retained on the filter for bioassay analysis is equivalent to 30 μg/m3 of PM plus 1 μg/m3 of PM2.5.
Fall 2008
By Wen-Whai Li
Air Pollution Effects

24. Data Processing for Chemical Concentrations
Determine the concentration of each compound on either filter (CF or CC) by multiplying the compound concentration in solution by the amount of solution
Determine the air concentration of each compound in either size category by using paired concentrations and the two dichotomous equations.
Fall 2008
By Wen-Whai Li
Air Pollution Effects

25. Composite Samples
Composite each pair of PM2.5 and PM samples for bioassay effects of PM10 for the same sample duration at the same location.
Composite multiple PM2.5 filters for bioassay effects of concentrations at k·(FF/FT)·∑CF, where k is a dilution factor.
Composite multiple PM filters for bioassay effects of concentrations at
k·{(FT-FF)/FT)·∑CF + ∑CC}, where k is a dilution factor.
May be used together to evaluate incremental effects.
Fall 2008
By Wen-Whai Li
Air Pollution Effects

26. Uncertainties Instrumentation Field Operations Laboratory Operations
Loss of mass
Size cut-off
Humidity
Field Operations
Flow Rates
Filter Handling
Laboratory Operations
Gravimetric Weighing
Temperature
Electrostatics
Fall 2008
By Wen-Whai Li
Air Pollution Effects