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ENGI 9628

Environmental Laboratory

Lab # 7

TSP and PM10

Faculty of Engineering & Applied Science

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Part I: PM10 Critical Flow High-Volume Sampler

OBJECTIVE

To determine concentration of particulate matters which are less than or equal to 10

micron (μm) in the air using PM10 Critical Flow High-Volume Sampler.

WHAT IS PARTICULATE MATTER?

Particulate Matter (PM) can be defined as all airborne liquid and solid particles, except

pure water, that are microscopic in size.

Coarse inhalable particulate matters are in the range of diameter < 10 µm and > 2.5 µm

whereas fine PM are of diameter < 2.5 µm. Both coarse and fine PM is of greatest

concern to human health, and in visibility reduction. In common terminology PM10 refers

to all particles less than or equal to 10 µm.

BACKGROUND

Particulate matter is ubiquitous, and is emitted both from natural and anthropogenic

sources. Mostly the fine fraction of PM10 and its precursor gases are originated from

combustion processes and vegetative burning. Whereas the coarse fraction of PM10 are

associated with mechanical processes such as wind erosion, breaking ocean waves and

grinding operations, as shown in the following table.

Figure 1, Illustrates the chemical composition of PM according to size, and also the

contribution of precursor gases to PM2.5

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Extremely small (ultrafine) particles less than 0.1 µm in diameter (the nuclei mode) are formed primarily from the condensation of hot vapours during high temperature combustion processes.

Particles of size 0.1-2.0 µm result from the coagulation of particles in the nuclei mode and from the condensation of vapours onto existing particles, which then grow into this size range. These fine particles can remain in the atmosphere for days to weeks. Particles larger than 2.5 µm (coarse) are in the atmosphere for shorter periods of few hours to few days. They contribute little to particle number concentrations but significantly to the total particle mass.

HUMAN HEALTH EFFECTS OF PARTICULATES MATTER

Particulate matters affect the cardio-respiratory (heart-lung) system of human body.

Smaller the particles, deeper it penetrate into the lungs, and causes greater risk of

inducing a negative reaction. Particles greater than 10 µm are mostly caught in the nose

and throat, but particles smaller than 10 µm (PM10) are breathed into the lungs and are

called inhalable particles. The bigger particles in these are caught by cilia lining (walls

of the bronchial tubes) which moves these particles up and out. PM2.5 can penetrate

deeper into the lungs where there are no cilia, these particles are removed by slower

mechanism. PM2.5 is sometimes called as respirable particles. Studies show that the

effects of PM on human health are lung infections, asthma, chronic bronchitis and

emphysema (the later two are known as Chronic Obstructive Lung Disease) and various

forms of heart diseases.

Table-2 describes the mean particle levels and health effects. It has not yet been possible

to conclude absolutely that what aspect of PM (size, mass, or composition) is directly

responsible for the observed health impacts, but still sufficient information exists about

human health effects to force the reduction of emission of PM.

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DESCRIPTION AND OPERATION OF PM10 (CFHVS)

The Critical Flow High Volume Sampler (CFHVS) contains three major components

i) Inlet

ii) Shelter

iii) Critical Flow Device

1. Inlet

The inlet (Figure-1) utilizes an omni-directional cyclone for fractionation, which allows aerosol/air entry from all angles of approach. Air entering through the aerodynamic inlet pathways passes through an insect screen, then into the evenly spaced entrance vanes of two-dimensional nature. As the aerosol enters the inlet it follows the fluid streamlines along the lower radius and enters the cyclone fractionator through the vane system- The oil-coated surface of the cyclone tube acts as a perfect absorber, which eliminates particle bounce and re-entrainment. The flow with un-removed particles then enters to an intermediate tube where the trajectory is altered to an upward direction. An additional turn is made to alter the flow to a downward trajectory to allow the remaining aerosol (PMio fraction) ultimately to deposit on a filter substrate for subsequent analysis.

2. Shelter

A one-piece shelter provides strength and protects the sampler from dust. A blower

out let baffle plate is installed in it. Air exits through six sides exhaust ports. This

protects the filter contamination from re-aerosolized dust.

3. Critical Flow Device

The Wedding Critical Flow Device (Figure-2) is one-piece molded fiberglass with a highly polished inner surface. A motor/blower is installed, and a precision orifice is available as an option for the constant monitoring of flow rate characteristics with a pressure-recording device.

When the pressure drop across the orifice/throat is very large (and especially for fairly

small orifice area less than 1/25 of the upstream area) then the velocity reaches to

sonic velocity. The flow at sonic velocity is said to be chocked and

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maintains steadily across the throat. Whenever this condition occurs, a stable shock

wave is created and is maintained within the throat portion of the Wedding Critical Flow

Device. If a sufficient vacuum is maintained downstream of the throat, then the shock

wave will limit the flow of air through the device to an absolute maximum. In this

situation, the flow rate is unaffected by the changes in the exhaust condition, such as

motor/blower speed or exit pressure.

Thus, whenever you turn on the sampler the flow remains constant in the choked

condition with no adjustment required and no detailed calibration is then required (rather,

a one point check would be sufficient).

LABORATORY TASKS

In this lab you are required to provide:

1. The location of sampling point

2. All the sampling and calibration calculations

3. Your result and analysis, and recommendations to control any particulate matters observed in this lab

4. Information on other materials on the filter, which can be analyzed.

PM10 SAMPLE PROCEDURE

i. Weigh the filter paper prior to use. Ensure that the scale doors are closed and

that the weight has stabilized.

ii. Calibrate the PM10 according to the information provided on the handout and the

specifications outlined in the users manual.

iii. Place a 8 inch by 10 inch clean filter (rough side up) on the screen located in the

lower piece of the filter cassette of the PM10 sampler. Record the time on the

PM10 timer. Leave the sampler running for a period of approximately 24

hours.

iv. After 24 hours, note the time on the timer, remove the filter paper, carefully fold

it in half (particulate sides together) and weigh it.

v. Calculate the air particulate loading averaged over 24 hours in µg/m3.

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CALIBRATION

1. Connect the sampler motor/blower power line from the timer to the high

volume sampler.

2. Install one micro-quartz filter in the sampler.

3. Leave the motor/blower to run for five minutes to achieve the actual run

temperature conditions.

4. Attach the monometer to the stagnation pressure tap on the sampler. Make

sure that the monometer reads zero.

5. Record the monometer reading in inches of water (ΔP = RHS + LHS). If ΔP

is determined in inches of water, then

in Hg = in H2O/13.6

6. Determine the ambient atmosphere pressure (Po = Pa) in inches of Hg on the

calibration worksheet form

Pa(mmHg) = Po = [29.92- Elevation of Sampler (feet) / 1000] * 25.4

7. Calculate the stagnation pressure (P1) as:

P1 = Po - ∆P

8. Read the ambient temperature (To) in degrees Fahrenheit or Celsius and

change it into R or K

R = oF + 460 or K =

oC + 273

9. Calculate the ratio P1/P0 and proceed to the look up table and read the Qo

value given in cubic feet per minute (CFM) or m3/min. Qo represents the

volumetric flow rate for these condition of P1 and To

10. Calculate the flow rate at EPA standard conditions by the following method

Qstd = Qo(Po/To)(Tstd/Pstd)

Where

Tstd = 298 K or 537 R and Pstd = 760 mmHg or 29.92 in. Hg

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After finishing the one-point calibration, the remaining calculations are straightforward.

Calculate the total volume of air that is sampled through the filter in the sampling time

from the equation given below

Vstd = Qstd * t

Where

Vstd = total air sampled (m3)

t = sampling time in minutes

To calculate the PM10 concentration, use the following relationship:

PM10 = (Wf – Wi)* 106/Vstd

Where

PM10 = Mass concentration of PM10 (µg/std m3)

Wf, Wi = final and initial weight of filter (gm)

REFERENCES

1. Environment Canada and Health Canada, May 2000. Priority Substances List Assessment Report, "Respirable Paniculate Matter Less Than or Equal to 10 Microns". (Cat. No. En40-215/47E)

2. Environment Canada, September 1990. A State of the Environment Report,

"Canadian Perspectives on Air Pollution". (Report No. 90-1)

3. Gregory D.W., 1994. Fundamentals of Air Sampling, Lewis Publisher London, U.K

4. Environment Canada, Ambient Particulate Matter An Overview

5. Wedding and Associates, 1992. Operation and Maintenance Manual for Critical Flow High-Volume sampler.

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CALCULATION SHEET

Site: Date: Operator (Group):

Site Elevation = ft

Weight of Clean Filter (Wi) = gm

Weight of Sampled Filter (Wf) = gm.

Initial Reading in the Sampler Timer (Ti) = minutes.

Final Reading in the Sampler Timer (Tf) = minutes.

Total Time of Sampling (t) = Tf – Ti = minutes.

Total Volume of Air Sampled, Vstd = Qsid * t = m3.

Concentration = (Wf – Wi) * 106 / Vstd = µg / std m

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Part 2: Total Suspended Particulate (TSP) Monitoring

OBJECTIVE

To determine Total Suspended Particulate concentration in air using a Hi Volume

sampler (TSP Sampler)

BACKGROUND

Total suspended particulate (TSP) Matters are in the form of solid matters or in the

liquid droplets. The origins of TSPs are smoke, dust, fuel ash, or condensation of vapours

that are suspended in the air. TSP originates from natural sources such as sea, soil, or

from man-made sources like diesel exhaust, construction activities and factories. TSP

also originates from combustion, or from sulphates and nitrates formed during sulphur

dioxide or nitrogen dioxide emissions. TSPs include range of different sized particles.

The coarser particles are 50 - 100 pm in size and finer particles are smaller sizes, usually

less than 10 µm in diameter.

The National Ambient Air Quality Objectives (NAAQOs) and the Canada Wide

Standards (CWSs) have currently proposed an acceptable level of 120 µg/m3 based on

24-hour averaging.

PRINCIPLE

Settleable particulates are usually measured by means of a dustfall bucket, while suspended particulate matter is often sampled by means of a high volume sampler or a paper tape sampler. The high volume sampler works on the principle of gravimetric method. A known volume of air is passed through a piece of filter paper that has been weighed previously. The filter paper is weighted again in the end to determine the increase in weight due to trapped particulates on the filter paper. The increase in weight divided by the volume of air passed through the filter gives the concentration of particulates in the air. The volume of air that is passed through the filter is determined by measuring both the rate at which the air is pumped through the filter paper and the duration of the pumping. Usually a manometer is used to determine the airflow rate.

In this laboratory exercise, the basic high volume sampler is calibrated and then used for sampling air particulate. The basic "hi-vol" is often called a lead sampler as in the past it has been used for sampling lead particulate but can be used to sample other inorganics including asbestos. Unlike the PM-10 which samples only the inhalable particulate; the basic "hi-vol" or Total Suspended Particulate "TSP" sampler samples all of the particulates suspended in the air. The TSP samplers have very wide acceptable air flow operating limits; 1.10 to 1.70 m

3/min. The sample is drawn by a strong vacuum pump across a filter. The

particulate is collected on the filter during a period usually 24 hours.

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High-VOLUME SAMPLING PROCEDURE

i. Weigh the filter before use. Make sure that the scale doors are closed and that the

weight has stabilized.

ii. Calibrate the hi-volume sampler according to the information provided in the

handout . To obtain a standard calibration, the calibration coefficient should be at

least 0.99.

iii. Check the flow rate, it should be in the range of 1.1 to 1.7 m3/min. If not, adjust it

and recalibrate the equipment.

iv. Place the filter in the filter casing on the sampler top (rough side up). Record the

time on the hi-volume sampler timer and the inside manometer reading. Leave the

sampler for a period of approximately 24 hours.

v. After 24 hours, note the time on the timer and record the manometer reading.

Carefully remove the filter. Fold it and weigh it.

vi. Calculate the flow rate through the filter using the average readings from the

manometer.

vii. Calculate the total suspended particulate matters loading in µg/m3, averaged over 24

hours.

viii. The particulate matter can then be viewed through an electron microscope.

CALIBRATION

i. Connect the sampler motor to the power source.

ii. Place the top loading adaptor on top of the filter holder and tighten it down.

iii. Place the 5 orifice plate in the top loading adopter.

iv. Attach the water manometer to the sampler. Connect one end of the manometer to

the top loading adapter and the other end to the atmospheric pressure. Make sure

that the manometer reads zero.

v. Turn on the sampler. Take the reading on the outside water manometer and record

it in the column labelled H2O (in) on the attached calibration sheet. Similarly take

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the reading from the inside manometer and place it in the column labelled I on the

calibration sheet.

vi. Repeat the same procedure for 7, 10, 13, & 18 orifice plates and take manometer

readings on both inside after each change of plates.

vii. Take the air temperature, ambient atmospheric pressure, sampler elevation, sampler

and orifice serial numbers and the orifice Q std slope and intercept with the date last

certified on the worksheet.

viii. Convert the manometer readings H2O (in) to standard flows using the orifice

calibration data slop (m) = 1.99 and intercept (b) = - 0.005002, using the following

formula

Qstd = 1/m * {[H2O (Pa/760) (298/Ta)]0.5

– b}

Where Ta = 273 + 0C

Pa = (29.92 – elevation (in ft)/1000) * 25.4

Ta and Pa are actual temperature and pressure respectively during calibration.

Evaluation of the 2nd floor of the S.J. Carew building ≈ 200 ft

Qstd reading for each plate are recorded in the calibration column titled Qstd.

ix. Correct inside manometer readings for current metrological conditions using the

formula

IC = I [(Pa/760) (298/Ta)]0.5

x. Plot the Qstd (x) VS IC (y) on the respected “x” and “y” axis on a graph paper or on

the MS Excel.

xi. Calculate the value of slope (m) and intercept (r) of the line generated from the

following formulas

m= {Σxy – [(Σx *Σy)/n]}/{Σ(x)2 – [(Σx)

2/n]}

where

Σxy = (x1y1) + (x2y2) + …

Σ(x)2 = (x1)

2 + (x2)

2 + …

(Σx)2 = [(x1) + (x2) + …]

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n = number of readings

Similarly the intercept (b) can be calculated as

B = y* – mx*

where

y* =Σy/n

x* =Σx/n

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xii. Calculate the correlation coefficient (r) as known below for the line generated and it

should be greater than 0.990.

(r) = {Σxy – [(ΣxΣy)/n]}/{ [Σ(x)2 – (Σx)

2/n][Σ(y)

2 – (Σy)

2/n]}

0.5

xiii. Determine the actual air flow rate through the sampler. Note the inside manometer

initial and final reading and then calculate the air flow rate in m3/min using the

formila given below

Q = 1/m * { [I [Pav/760) (298/Tav)]0.5

– b}

The flow rate should be within the range of 1.1 to 1.7 m3/min. Where, Tav and Pav are the

daily average temperature and pressure respectively.

After calibration and actual flow rate “Q” determine the total suspended particulate

concentration in air using the following equation:

C = (Wf – Wi) * 106 /V

Where

Wf and Wi are the final and initial weights of the filter respectively (gms)

V = total volume of air sampled (m3) and

V = Q * t

t = time in minutes

Q = actual flow rate in m3/minute

REPORTING

The report should include all the calculations involved in the calibration, the estimation

of the flow rate and the air particulate loading (in µg/m3 & g/m

3). The sources and types of

air particulate should be described. The results are to be compared with those in the

literature and also with the standards.

REFERENCES

1) Peavy, H.S., Rowe, D.R., and G. Tchobanoglous, Environmental Engineering, McGraw

Hill.

2) Operations Manual, Graseby Model GL2000H Total Suspended Particulate Sampling

System, Cleves, Ohio.

3) Environment Canada, September 1990. A State of the Environment Report,

"CanadianPerspectives on Air Pollution". (Report No. 90-1)

4) Gregory D. W., 1994. Fundamentals of Air Sampling, Lewis Publisher London, U.K

5) Environment Canada, Ambient Particulate Matter An Overview

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CALCULATION SHEET

Site: Date: Operator (Group):

Site Elevation = ft

Weight of Clean Filter (Wi) = gm

Weight of Sampled Filter (Wf) = gm.

Initial Reading in the Sampler Timer (Ti) = minutes.

Final Reading in the Sampler Timer (Tf) = minutes.

Total Time of Sampling (t) = Tf – Ti = minutes.

Total Volume of Air Sampled, V = Q * t = m3.

Concentration = (Wf – Wi) * 106 / Vstd = µg / std m

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