SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT

METHOD 5.1

DETERMINATION OF PARTICULATE MATTER EMISSIONS FROM

STATIONARY SOURCES USING A WET IMPINGEMENT TRAIN

OFFICE OF OPERATIONS

TECHNICAL SERVICES DIVISION

MARCH 1989
METHOD 5.1

DETERMINATION OF PARTICULATE MATTER EMISSIONS FROM

STATIONARY SOURCES USING A WET IMPINGEMENT TRAIN

TABLE OF CONTENTS

Section

1. Overview

1.1 Principle

1.2 Applicability

2. Field Procedures

2.1 Sampling Apparatus

2.2 Sampling Reagents

2.3 Pretest Determinations

2.4 Gas Volume Meter Checks

2.5 Pretest Preparation

2.6 Leak Checks

2.7 Sampling Train Operation

2.8 Calculation of Percent Isokinetic

2.9 Sample Handling

2.10 Calibration

3. Laboratory Procedures
3.1 Apparatus

3.2 Reagents

3.3 Pretest Preparation

3.4 Preparation of Sample Collection Train

3.5 Sample Collection Train Leak Check

3.6 Sample Recovery

3.7 Analysis

3.8 Calculations and Reporting

3.9 Calibrations

4. Engineering Calculations and Reporting

4.1 Calculations

5.1-1

METHOD 5.1

DETERMINATION OF PARTICULATE MATTER EMISSIONS FROM

STATIONARY SOURCES USING A WET IMPINGEMENT TRAIN

Section 1 of 4

1. Overview

1.1 Principle

A sample of stack gases is withdrawn

isokinetically from the source through a sample

train. Particulate matter is collected in

impingers containing deionized water and on a

backup filter. The impingers are contained in an

ice bath to maintain a sampled gas temperature of

approximately 15oC (60oF). The filter is not

heated.

Total particulate matter mass is defined as the

sum of the mass collected in the impingers and

probe, and on the filter after removal of

combined water, plus extractable organic matter.

Solid particulate matter mass is defined as the

total particulate matter mass minus extractable

organic matter and sulfuric acid. An adjustment

to the total particulate matter mass is allowed
5.1-2

for sulfuric acid formed from reactions between

SO2 and SO3 with the sample train components.

When ammonia is injected to enhance the

efficiency of a control device, a second

adjustment is allowed for neutral sulfates.

This adjustment is allowed for fluid catalytic

cracking units only.

Because of the complexity of this method,

personnel involved in both the collection and

analysis of samples must be trained and

experienced in the test procedures.

1.2 Applicability

This method is used to measure particulate

emissions from stationary sources, except when

determining compliance with New Source

Performances Standards. When the particulate

matter is hygroscopic, SOx is present in

concentrations greater than 10 ppm, or ammonia is

injected to enhance control device efficiency, an

in-stack filter or a heated filter before the

impingers is recommended.
5.1-3

METHOD 5.1

DETERMINATION OF PARTICULATE MATTER EMISSIONS FROM

STATIONARY SOURCES USING A WET IMPINGEMENT TRAIN

Section 2 of 4

2. Field Procedures

2.1 Sampling Apparatus

2.1.1 Sampling Train

A schematic of the sampling train used in

this method is shown in Figure 5.1-1.

The sampling train consists of the

following components:

a. Probe Nozzle

The nozzle material should be 316

stainless steel or glass, with a

sharp, tapered leading edge. The

taper angle should be < 30o and on the

outside, to preserve a constant

internal diameter. The stainless
5.1-4

steel nozzle should be constructed

from seamless tubing. Other materials

which will not be corroded by the

sampled gases or interfere with sample

recovery may be used.

A range of nozzle sizes suitable for

isokinetic sampling should be

available in increments of 0.16 cm

(1/16 in.), e.g. from 0.32 to 1.27 cm

(1/8 to 1/2 in.) or larger if higher

volume sampling trains are used.

Each nozzle must be calibrated before

its use in the field. Measure the

inside diameter of the nozzle with a

micrometer to the nearest 0.025 mm

(0.001 in.). Make three separate

measurements using different diameters

each time, and obtain the average.

The difference between the high and

low numbers shall not exceed 0.1 mm

(0.004 in.). Nicked, dented, or

corroded nozzles must be reshaped,

sharpened, and recalibrated before

use.
5.1-5

Connect the nozzle to the liner with a

leak-free fitting resistant to heat

and chemicals.

b. Probe Liner

Use borosilicate or quartz probe

liners for stack temperatures up to

about 480oC (900oF); use quartz liners

for temperatures between 480 and 900oC

(900 and 1,650oF). If high

temperatures are encountered see

Chapter X section on Sampling High

Temperature Sources.

Whenever practical, use borosilicate

or quartz glass probe liners.

Otherwise, use metal liners made of

seamless tubing (e.g. 316 stainless

steel, Inconel 825, or other corrosion

resistant metals) when acid

particulates are present in

concentrations less than 1 mg/m3 at

probe conditions or SO2 is less than

20 ppm.
5.1-6

When assembling the probe and nozzle,

verify that all components, including

ferrules and other connectors, are

heat-resistant, leak-free and noncontaminating for the sample.

The liner may be connected to the

impingers rigidly with glass, or

flexibly with inert vacuum tubing.

c. Pitot Tube

Use an S-type Pitot tube as described

in Section 1.1 of Method 2.1, or other

device approved by the Executive

Officer. Attach the Pitot tube to the

probe, as shown in Figure 5.1-1, to

allow constant monitoring of the stack

gas velocity. If this is not

practical see Chapter X, section on

Flue Factor.

The impact (high pressure) opening

plane of the Pitot tube must be even

with or above the nozzle entry plane

(see Method 2.1) during sampling. The

S-type Pitot tube assembly must have a
5.1-7

known coefficient, as determined in

Method 2.1.

d. Differential Pressure Gauge

Use an inclined manometer or

equivalent device, as described in

Method 2.1, for stack velocity head

readings, and a separate manometer for

orifice differential pressure

readings.

e. Filter Holder

Use a borosilicate glass filter

holder, with a glass frit filter

support and a silicone rubber gasket.

Other materials such as stainless

steel, Teflon, or Viton may be used if

they do not react with the particulate

matter or sample gases. (Reactions

normally are not a problem after the

impingers.) The holder design

provides a positive seal against

leakage from the outside or around the

filter. Attach the holder after the

dry impinger in the impinger train.
5.1-8

f. Impinger Train

The train consists of four GreenburgSmith design impingers connected in

series with leak-free ground glass

fittings, or any similar leak-free

non-contaminating fittings. The first

and second impingers must be of the

Greenburg-Smith design with the

standard tip. The third and fourth

impingers must be of the GreenburgSmith design, modified by replacing

the tip with 1.3 cm (1/2 in.) ID glass

tube extending to about 1.3 cm (1/2

in.) from the bottom of the flask.

Acceptable modifications include the

following: using non-reactive flexible

connections between the impingers,

using materials other than glass, or

using flexible vacuum lines to connect

the filter holder to the impinger

train.

The first and second impingers contain

100 ml of deionized water (run blanks

prior to field use), the third is
5.1-9

empty, and the fourth contains a known

weight of 6 to 16 mesh indicating-type

silica gel or equivalent. Place a

thermometer capable of measuring

temperature to within 1oC (2oF) at the

outlet of the fourth impinger to

monitor outlet gas temperature. In

certain applications an extra dry

impinger with a shortened straight

stem may be placed before the wet

impinger to act as a drop out for

particulates that cause excessive

foaming, or when there is excessive

moisture.

Instead of using silica gel the

moisture leaving the third impinger

may be measured by monitoring the

temperature and pressure at the exit

of the impinger train and using

Dalton's law of partial pressures.

Even if means other than silica gel

are used to determine the amount of

moisture leaving the impinger train,

silica gel, or equivalent should be

used between the impinger system and
5.1-10

pump to prevent moisture condensation

in the pump and metering devices.

g. Metering System

The metering system includes vacuum

gauge, leak-free pump, thermometers

capable of measuring temperature to

within 3oC (5.4oF), dry gas meter

capable of measuring volume to within

2 percent, and related equipment, as

shown in Figure 5.1-1. An alternative

to the thermometer and dry gas meter

is an equivalent temperaturecompensated dry gas meter. When the

metering system is used in conjunction

with a Pitot tube, the system should

allow for checks of isokinetic rates.

2.1.2 Barometer

A mercury, aneroid, or other barometer

capable of measuring atmospheric pressure

to within 2.5 mm (0.1 in.) Hg is used.

The barometric pressure may be obtained

from a nearby National Weather Service

(NWS) station. Request the station value
5.1-11

(which is the absolute barometric

pressure) and adjust for elevation

difference between the NWS station and the

sampling point at the rate of minus 2.5 mm

(0.1 in.) Hg per 30 m (100 ft) elevation

increase or plus the same adjustment for

elevation decrease.

2.1.3 Temperature Determination Equipment

Use the temperature sensor described in

Method 2.1. Preferably, the temperature

sensor should be permanently attached to

the Pitot tube or sampling probe so that

the tip of the sensor extends beyond the

leading edge of the probe sheath and

touches no metal. Alternatively the

sensor may be attached just prior to use

in the field. If the temperature sensor

is attached in the field, place it in an

interference-free arrangement with respect

to the S-type Pitot tube openings (see

Method 2.1).

As another alternative, if a difference of

not more than 1 percent in the average

measurement and resulting stack flow rate
5.1-12

calculation would be introduced, the

temperature gauge need not be attached to

the probe or Pitot tube.

2.1.4 Gas Molecular Weight - Determination

Equipment

Same as Method 3.1. Concurrent

determination is not required when the

process is steady state and molecular

weight varies less than 2 percent.

2.2 Sampling Reagents

a. Filters

Glass fiber filters, without organic binder.

The filters should be at least 99.95 percent

efficient (< 0.05 percent penetration) on 0.3

micron dioctyl phthalate smoke particles.

Conduct the filter efficiency test in

accordance with ASTM Standard Method

D2986-71, or use test data from the

supplier's quality control program. Low

sodium filters are recommended when SO2 is

present.
5.1-13

b. Silica Gel

Indicating-type silica gel, 6 to 16 mesh.

Use new silica gel as received. If previously

used, dry at 175oC (350oF) for 2 hours.

Other types of desiccants may be used subject

to the approval of the Executive Officer.

c. Water

Deionized, distilled water to conform to ASTM

specification D1193-77 Type 3.

At the option of the chemist, the KMnO4 test

for oxidizable matter may be eliminated when

high concentrations of organic matter are not

expected to be present. Reference to water

throughout this method implies deionized,

distilled water.

Run blanks prior to field use to eliminate a

high blank on test samples.

d. Crushed Ice or Dry Ice Pellets
5.1-14

e. Stopcock Grease

Stopcock grease is not recommended and not

necessary if screw-on connectors with Teflon

sleeves or similar are used. Acetoneinsoluble, heat-stable silicone grease may be

used. Other types of grease may be used,

subject to the approval of the Executive

Officer.

2.3 Pretest Determinations

Select the sampling site and the minimum number

of sampling points according to Method 1.1. If

it is not possible to follow Method 1.1, or more

than one sample site must be tested, see Chapter

X. Determine the stack pressure, temperature,

and the range of velocity heads using Method 2.1.

Determine the moisture content, using Method 4.1

or its alternative, to make sampling rate

settings.

Determine the stack gas dry molecular weight as

described in Method 3.1. If integrated sampling

(Method 3.1) is used for molecular weight

determination, take the integrated bag sample
5.1-15

throughout the total time of the particulate

sample run, unless the effect on the velocity

measurement and resulting stack flow rate

calculation is less than 1 percent. In that case

take the integrated sample immediately before,

after, or for a shorter time during the

particulate sample run.

Select a nozzle size based on the range of

velocity heads encountered, so that it is not

necessary to change the nozzle size to maintain

isokinetic sampling rates. Do not change the

nozzle size during the run. Choose the

differential pressure gauge appropriate for the

range of velocity heads encountered (see Method

2.1).

Select a probe length suitable for sampling all

traverse points. Consider sampling large stacks

from opposite sides (four sampling port holes) to

reduce probe lengths.

Select a total sampling time equal to or greater

than the minimum total sampling time specified in

test procedures for the specific industry. The

sampling time per point must not be less than 2

minutes and the total sample volume taken
5.1-16

(corrected to standard conditions) must not be

less than 30 ft3.

To avoid timekeeping errors, it is recommended

that the number of minutes sampled at each point

should be an integer or an integer plus one-half

minute. The sampling time should be the same at

each point. In some circumstances, e.g. batch

cycles, it may be necessary to sample for shorter

times at the traverse points, resulting in

smaller gas sample volumes. In these cases, test

two or more cycles.

2.4 Gas Volume Meter Checks

Check the meter against the −H@ orifice

calibration obtained in Chapter III without the

probe, filter and train connected. A pretest

check is recommended. A post test check is

mandatory.

Check the calibration of the metering system by

performing calibration runs at three different

flow rates. Set the flow rates at 0.4 cfm + 10

percent, 0.7 cfm + 10 percent, and

1.0 cfm + 10 percent. The calibration will be
5.1-17

used to calculate −H@ at these three flow rates,

where −H@ is calculated as follows:

TmO2

∆H@ = 0.0319 _∆H --------------

Pbar (Y2Vm

2A2)

where:

−H@ = Average pressure differential across the

orifice meter, in. H2O at 0.75 scfm

(528oF, 29.92 in. Hg)

Tm = Absolute average dry gas meter

temperature, oR

Pbar = Barometric pressure, in. Hg

O = Total sampling time, min

Y = Dry gas meter calibration factor,

dimensionless, obtained from percent

Chapter III

−H = Pressure differential across the

orifice, in. H2O
5.1-18

Vm = Volume of gas sample as measured by

dry gas meter, dcf

0.0319 = (0.0567 in. Hg/oR) x (0.75 cfm)2

A = 1, if meter is not temperature

compensated

Tm

= ,

Compensated Temp. (oR)

if temperature compensated.

If the measured −H@ differs by more than + 3

percent of the actual −H@ obtained in Chapter

III, the results of the tests are voided.

An alternative procedure (e.g. using an orifice

meter with a known K-Factor) may be used, subject

to the approval of the Executive Officer.

2.5 Pretest Preparation

Set up the train as in Figure 5.1-1.

Mark the probe with heat resistant tape or by

some other method to denote the proper distance
5.1-19

to insert the probe into the stack or duct for

each sampling point.

Place crushed ice or dry ice pellets around the

impingers.

2.6 Leak Checks

2.6.1 Pretest Leak Check

If a Viton A O-ring or other leak-free

connection is used in assembling the probe

nozzle to the probe liner, leak check the

train at the sampling site by plugging the

nozzle and drawing a 380 mm (15 in.) Hg

vacuum.

A lesser vacuum may be used if it is not

exceeded during the test. The probe may

be leak checked separately at a pressure

equal to the stack pressure minus 25 mm (1

in.) Hg. Alternatively, the probe may be

leak checked with the rest of the sampling

train, at 380 mm (15 in.) Hg vacuum.

A leakage rate in excess of either 4

percent of the average sampling rate or
5.1-20

0.00057 m3/min (0.02 cfm), is

unacceptable.

Start the pump with the bypass valve fully

open and the coarse adjust valve

completely closed. Partially open the

coarse adjust valve and slowly close the

bypass valve until the desired vacuum is

reached. Do not reverse direction of

bypass valve; this will cause water to

back up into the probe. If the desired

vacuum is exceeded, either leak check at

this higher vacuum or end the leak check

as shown below and start over.

When the leak check is completed, slowly

remove the plug from the inlet to the

probe, and then turn off the vacuum pump.

This prevents the water in the impingers

from being forced backward into the filter

holder and silica gel from being entrained

into the third impinger.

Perform a leak check of the Pitot lines.

(See Method 2.1).

2.6.2 Leak Check During Sampling Run
5.1-21

If a component change (e.g. filter

assembly or impinger) becomes necessary

during the sampling run, conduct a leak

check immediately before the change is

made. Use the pretest leak check

procedure, but use a vacuum equal to or

greater than the maximum value recorded up

to that point in the test.

If the leakage rate is not greater than

either 0.00057 m3/min (0.02 cfm) or 4

percent of the average sampling rate, the

results are acceptable and no correction

has to be applied to the total volume of

dry gas metered. However, if the leakage

rate exceeds either of these limits, the

tester must either record the leakage rate

and correct the sample volume as shown in

Chapter X, Section 7, or void the sampling

run immediately after component change.

2.6.3 Post Test Leak Check

A leak check is mandatory at the

conclusion of each sampling run. Follow

the procedures outlined in Section 2.6.1
5.1-22

at a vacuum equal to or greater than the

maximum value reached during the sampling

run.

Compare the leakage rate to the limits

indicated in Section 2.6.2 and follow the

procedure described there.

2.7 Sampling Train Operation

During the sample run, maintain an isokinetic

sampling rate within 10 percent of true

isokinetic.

For each run, record the data required on the

data sheet shown in Figure 5.1-4. Be sure to

record the initial dry gas meter reading. Record

the dry gas meter readings at the beginning and

end of each sampling time increment, when changes

in flow rates are made, before and after each

leak check, and when sampling is halted.

Record other data required by the sheet in Figure

5.1-4 at least once for each sample point during

each time increment. Take additional readings

when significant changes (20 percent variation in
5.1-23

velocity head readings) require adjustments in

flow rate.

Level and zero the manometer and make periodic

checks during the traverse because the manometer

level and zero may drift due to vibrations and

temperature changes.

Clean the portholes prior to the test run to

minimize the chance of contamination. To begin

sampling, remove the nozzle cap and verify that

the Pitot tube and probe are properly positioned.

During the period before sampling, the nozzle can

be pointed downstream. Position the nozzle at

the first traverse point and rotate the nozzle

until the tip is pointing directly into the gas

stream before turning on the sampling pump.

Immediately start the pump and adjust the flow to

isokinetic conditions.

Use calculators or nomographs to determine

correct adjustment of the isokinetic sampling

rate.

When the stack is under significant negative

pressure (height of water in impinger stem), take
5.1-24

care to close the coarse adjust valve before

inserting the probe into the stack to prevent

water from backing into the probe. If necessary,

the pump may be turned on with the coarse adjust

valve closed.

When the probe is in position, block off the

openings around the probe and porthole to prevent

flow disturbance and dilution of the gas stream.

Traverse the stack cross section, as required by

Method 1.1. Be careful to avoid bumping the

probe nozzle into the stack walls when sampling

near the walls or when removing or inserting the

probe through the portholes. This minimizes the

chance of extracting stack deposits.

During the test run, periodically add ice to

maintain a temperature less than 15oC (60oF) at

the condenser/silica gel outlet. Also,

periodically check the level and zero of the

manometer. Note and investigate any changes in

stack temperature or velocity pressure over those

measured during previous tests or traverses.

Changes can mean failure of sampling equipment or

a change in process.
5.1-25

If the pressure drop of the filter becomes too

high, making isokinetic sampling difficult to

maintain, the filter may be replaced during a

sample run. Use another complete filter assembly

rather than attempting to change the filter

itself. Before a new filter assembly is

installed, conduct a leak check (see Section

2.6.2).

The total particulate weight includes the

summation of all filter assembly catches. Use a

single train for the entire sample run, except

when sampling is required in two or more ducts or

at two or more locations within the same duct, or

when equipment failure necessitates a change of

trains. When two or more trains are used,

separate analyses of each train must be

performed.

At the end of the sample run, turn off the coarse

adjust valve, remove the probe and nozzle from

the stack, turn off the pump, record the final

dry gas meter reading, and conduct a post test

leak check, as outlined in 2.6.3. Also, leak

check Pitot lines as described in Method 2.1.

The lines must pass this leak check to validate
5.1-26

the velocity head data. Perform a gas volume

meter check as described in Section 2.4.
5.1-27

2.8 Calculation of Percent Isokinetic

Calculate percent isokinetic, using the equation

shown in Figure 5.1-6, to determine whether the

run was valid or another test run should be made.

2.9 Sample Handling

Proper clean-up procedure begins as soon as the

probe is removed from the stack at the end of the

sampling period.

Allow the probe to cool. When the probe can be

safely handled, wipe off all external particulate

matter near the tip of the probe nozzle and place

a cap over it to prevent losing or gaining

particulate matter. Do not cap off the probe tip

tightly while the sampling train is cooling down.

This would create a vacuum in the probe, drawing

water from the impingers into the probe.

Before moving the sample train to the clean-up

site, remove the probe from the sample train,

wipe off any stopcock grease, and cap the open

outlets of the probe. Be careful not to lose any

condensate that might be present. Wipe any
5.1-28

stopcock grease off of the impinger train inlet

where the probe was fastened and cap it. Remove

the umbilical cord from the last impinger and cap

the impinger. If a flexible line is used between

the first impinger and the probe, disconnect the

line at the probe and let any condensed water or

liquid drain into the impingers. After wiping

off any stopcock grease, cap off the open inlet

of the flexible line opening. Either ground

glass stoppers, plastic caps, or serum caps may

be used to close these openings.

Transfer the probe and filter-impinger assembly

to the clean-up area. This area should be clean

and protected from the wind to reduce chances of

contaminating or losing the sample. It is

recommended that sample recovery be performed in

a controlled laboratory environment.

2.10 Calibration

See Chapter III.
5.1-29

METHOD 5.1

DETERMINATION OF PARTICULATE MATTER EMISSIONS FROM

STATIONARY SOURCES USING A WET IMPINGEMENT TRAIN

Section 3 of 4

3. Laboratory Procedures

3.1 Apparatus

3.1.1 Sampling Train

See Section 2.1.1.

3.1.2 Sample Recovery

a. Balance

The balance must be accurate to the

nearest 0.5 g.

b. Nylon Bristle Brushes with Stainless

Wire Handles.

The probe brush must have extensions

at least as long as the probe, and
5.1-30

made of stainless steel, Nylon, or

Teflon, or similarly inert material.

The brushes must be properly sized and

shaped to brush out the probe liner

and nozzle.

c. Wash Bottles

Glass wash bottles are recommended;

polyethylene wash bottles may be used

at the option of the tester.

d. Glass Sample Storage Containers

Use 500 ml or 1000 ml chemicallyresistant, borosilicate glass bottles.

Screw cap liners must be rubber-backed

Teflon or constructed to be leak-free

and resistant to chemical attack.

Narrow mouth glass bottles are less

prone to leakage. Alternatively,

polyethylene bottles may be used.
5.1-31

e. Petri Dishes

For filter samples, use glass or

polyethylene dishes, unless otherwise

specified by the Executive Officer.

f. Plastic Storage Containers

Air-tight containers to store silica

gel.

g. Funnel and Rubber Policeman

To aid in transfer of silica gel to

container; not necessary if silica gel

is weighed in the field.

h. Funnel

Glass or polyethylene, to aid in

sample recovery.

3.1.3 Analysis of Particulate Matter

a. Glass Weighing Dishes
5.1-32

b. Desiccator

Containing indicating-type calcium

sulfate or indicating-type silica gel

desiccant.

c. Analytical Balance

To measure to 0.1 mg.

d. Beakers

600 to 1000 ml, 150 ml.

e. Hygrometer

To measure the relative humidity of

the laboratory environment.

f. Temperature Gauge

To measure the temperature of the

laboratory environment.

g. Drying Oven

105oC+2oC (221 + 3.6oF).
5.1-33

h. Separatory Funnel

1000 ml.

i. Hot Plate

Heavy duty.

j. Ribbed Watch Glasses

k. Filtration Apparatus

Includes suction flask, filter holder

and vacuum pump.

l. Rubber Policeman

To aid in quantitative sample

transfer.

3.1.4 Acid and Sulfate Analysis

a. Beakers

400 or 600 ml.
5.1-34

b. Buret

10 ml or 50 ml (0.02 divisions), or

autotitrator.

c. Hot Plate

Heavy duty.

d. Furnace

800-900oC (1470-1650oF).

e. Crucibles

Gooch, 20-40 ml. Prepared with

asbestos mat and tared after 900oC

(1650oF) and 6 hours desiccation.

f. Crucible tongs.

g. Analytical Balance

To measure to 0.1 mg.
5.1-35

h. Desiccator

Containing indicating-type calcium

sulfate or indicating-type silica gel

desiccant.

i. Hygrometer

To measure relative humidity.

j. Temperature Gauge

To measure the temperature of the

laboratory environment.

k. Pipet

Graduated 25 ml, in 1 ml increments.

l. Sample Containers

To hold filter and impinger residue.

m. Stirring Rods

Glass.
5.1-36

n. Watch Glass

Ribbed, to cover beakers.

o. Filtration Apparatus

Includes suction flask, filter holder

and vacuum pump.

p. Steam Bath.

3.2 Reagents

3.2.1 Sample Collection Train Preparation

a. Filters

Same as Section 2.2 a.

b. Silica Gel

Same as Section 2.2 b.

c. Water

Same as Section 2.2 c.
5.1-37

d. Crushed Ice or Dry Ice Pellets

e. Stopcock Grease

Same as Section 2.2 e.

3.2.2 Sample Recovery

a. Water

Same as Section 3.2.1 c.

3.2.3 Analysis of Particulate Matter

a. Water

Same as Section 3.2.1 c.

b. Desiccant

Indicating-type anhydrous calcium

sulfate, or silica gel (see Section

3.2.1 b.
5.1-38

c. Organic Solvent

Reagent grade dichloromethane with

< 0.001 percent residue.

3.2.4 Reagents for Analysis of Sulfuric Acid and

Sulfates

a. Water

Same as 2.2 c.

b. Sodium Hydroxide 0.1N

Dissolve 4.00 grams of sodium

hydroxide in 200 ml of carbon-dioxide

free water. Dilute to 1 liter with

carbon dioxide free water.

Standardize and protect from exposure

to air.

c. Methyl Orange Indicator

Aqueous.
5.1-39

d. Barium Chloride Solution, 10 Percent

Dissolve 100 grams of barium chloride

dihydrate with 900 ml of water.

e. Hydrochloric Acid (HCl)

Concentrated.

f. Hydrochloric Acid (HCl) 0.1N

(Approximately)

Dilute 8.3 ml concentrated HCl to 1

liter water.

g. Silver Nitrate Test Solution

3.3 Pretest Preparation

All equipment, including balances, oven

temperature, glassware, and safety equipment

should be checked for readiness before

proceeding. Weigh several 200 to 300 g portions

of silica gel in air-tight containers to the

nearest 0.5 g. Record the total weight of the

silica gel plus container, on each container. As
5.1-40

an alternative, the silica gel may be weighed

directly in its impinger or sampling holder just

prior to train assembly.

Check filters visually against light for

irregularities, flaws, or pinhole leaks. Label

filters of the proper diameter on the back side

near the edge using numbering machine ink. As an

alternative, label the shipping containers (glass

or plastic petri dishes), and keep the filters in

these containers at all times except during

sampling and weighing.

Desiccate the filter at 15 + 5.6oC (60 + 10oF)

and ambient pressure for at least 24 hours.

Weigh at intervals of at least 6 hours to a

constant weight (i.e. 0.5 mg change from previous

weighing); record each weight to the nearest 0.1

mg. During each weighing the filter must not be

exposed to the laboratory atmosphere for a period

greater than 2 minutes and a relative humidity

above 50 percent. Alternatively, the filters may

be oven dried at 105oC (220oF) for 2 to 3 hours,

desiccated for 2 hours, and weighed.
5.1-41

3.4 Preparation of Sample Collection Train

During preparation and assembly of the sampling

train, cover all openings wherever contamination

can occur until just prior to assembly. Assemble

the impingers in the tray as shown in Figure 5.1-

1. Load each of the first two impingers with

exactly 100 ml of water. Leave the third

impinger empty. Place approximately 200 to 300 g

of silica gel in the fourth impinger and record

its weight to the nearest 0.5 g. More silica gel

may be used, but ensure that it is not entrained

and carried out of the impinger during sampling.

If moisture content is to be determined

gravimetrically, weigh each impinger plus its

contents to the nearest 0.5 g and record the

weights.

Using a tweezer or clean disposable surgical

gloves, place a weighed and identified filter in

the filter holder. Be sure that the filter is

properly centered and the gasket properly placed

to prevent the sample gas stream from

circumventing the filter. Check the filter for

tears after assembly is completed.
5.1-42

When using a glass liner, install the selected

nozzle using a Viton A O-ring when stack

temperatures are less than 260oC (500oF), and an

asbestos string gasket when temperatures are

higher (consult with source testers). Teflon

ferrules may also be used for temperatures less

than 350oF. With metal liners, install the

nozzle as above or by a leak-free direct

mechanical connection. Set up the train as in

Figure 5.1-1 using a very light coat of stopcock

grease on ground glass joints, greasing only the

outer portion to avoid the possibility of

contamination by the stopcock grease. Use of

stopcock grease is not recommended unless it is

absolutely necessary. Connect the impingers, and

seal the train or its components for transport to

the sampling site.

3.5 Sample Collection Train Leak Check

The sample collection train may be leak checked

in the laboratory after assembly using the

procedure in Section 2.5.

3.6 Sample Recovery
5.1-43

In most cases the intact and secured train is

delivered to the laboratory for subsequent

recovery. Occasionally, conditions demand that

recovery be made by source testers in the field,

but this is not recommended as a standard

procedure. The following discussion is directed

to source test or laboratory personnel. The

latter should determine when laboratory recovery

methods should be used. If the train is

recovered in the field, collect the sample in

leak-free containers, which are subsequently

recovered in the laboratory (Section 3.6.5). If

the train is recovered in the laboratory, collect

the sample in analytical glassware, and delete

container recovery.

Inspect the train for general condition. Note if

the silica gel is completely expended, and if the

train or its components are sealed. Note any

unusual conditions that may affect results,

including torn filters, cloudiness in the

impinger liquids, etc.
5.1-44

3.6.1 Filter

Working in an area that is protected from

the wind and free from dust, disconnect

the filter holder from the rest of the

train. Carefully remove the filter from

the filter holder and place it in its

identified petri dish container. Use a

pair of tweezers and/or clean disposable

surgical gloves to handle the filter. If

it is necessary to fold the filter, fold

the particulate cake to the inside.

Carefully transfer to the petri dish any

particulate matter and/or filter fibers

which adhere to the filter holder gasket

by using a dry nylon bristle brush and/or

a sharp-edged blade. Seal the container.

3.6.2 Probe and Nozzle

Wipe the connection of the probe and

train, and disconnect the probe from the

train. During the probe and nozzle

recovery, keep the remainder of the train

sealed to prevent any contamination from

occurring. Wipe down the outside of the

probe and nozzle. Taking care to see that
5.1-45

dust on the outside of the probe or other

exterior surfaces does not get into the

sample, quantitatively recover particulate

matter or any condensate from the probe

nozzle, probe fitting, and probe liner by

washing these components with water and

placing the wash in a sample container.

Carefully remove the probe nozzle and

clean the inside surface by rinsing with

water from a wash bottle and brushing with

a Nylon bristle brush. Brush until the

rinse shows no visible particles, then

make a final rinse of the inside surface

with water. Similarly, brush and rinse

the inside parts of the Swagelok fitting

with water until no visible particles

remain.

Rinse the probe liner with water by

tilting and rotating the probe while

squirting water into its upper end so that

all inside surfaces are wetted. Let the

water drain from the lower end into the

sample container. A glass or polyethylene

funnel may be used to transfer liquid

washes to the container.
5.1-46

Follow the water rinse with a probe brush.

Hold the probe in an inclined position and

squirt water into the upper end as the

probe brush is being pushed with a

twisting action through the probe. Hold a

sample container underneath the lower end

of the probe and catch any water and

particulate matter which is brushed from

the probe. Run the brush through the

probe three or more times until no visible

particulate matter is carried out with the

water or until none remains in the probe

liner on visual inspection.

With stainless steel or other metal

probes, run the brush through in the above

prescribed manner at least six times,

since metal probes have small crevices in

which particulate matter can be entrapped.

Rinse the brush and quantitatively collect

these washings in the sample container.

After the brushing, make a final rinse of

the probe.

To reduce sample losses, it is recommend

that two people clean the probe. Between
5.1-47

sampling runs, keep brushes clean and

protected from contamination.

If the sample is recovered in the field,

tighten the sample container lid and mark

the fluid level to indicated if leakage

has occurred during transport. Label the

container to clearly identify its

contents.

3.6.3 Impinger Catch

Wipe any dust or grit or water from the

outside of the impingers, especially near

the impinger joint. Carefully disconnect

the impingers. Weigh the impingers plus

content to the nearest 0.5 g and record

the weights. Transfer the catch to a

sample container. Clean all surfaces by

rubbing them with a Nylon bristle brush

and rinsing with water three times or more

if necessary to remove visible

particulates. Make a final rinse of each

component and the brush.

If this recovery is performed in the

field, tighten the sample container lid

and mark the fluid level to indicate if
5.1-48

leakage has occurred during transport.

Label the container to clearly identify

its contents.

3.6.4 Silica Gel

Transfer the silica gel to its container

and tighten the lid. Alternatively, weigh

the impinger plus content to the nearest

0.5 g and record this weight, or seal the

impinger for return to the laboratory.

3.6.5 Container Recovery

If the sample has been recovered in the

field, check all the sample containers to

ensure that no sample was contaminated or

lost during transport.

For a liquid catch, note the liquid level

in the container and determine if

noticeable leakage has occurred. If so,

void the entire sample. Wipe the cap area

and transfer the sample to a beaker.

Carefully rinse the cap and container into

the beaker, tilting the container and

using a brush if necessary to dislodge
5.1-49

particulate matter. Record the total

volume to the nearest 10 ml, and proceed

with the analysis.

Combine the probe and impinger catches.

Note whether the silica gel, impinger, or

container was properly sealed; weigh and

record to the nearest 0.5 g.

3.7 Analysis

The South Coast Air Quality Management District

has separate rules regulating the emissions of

total and solid particulate matter and therefore

it is necessary to analyze for both solid and

liquid particulates from a single particulate

sample. The only liquid particulates routinely

analyzed are organics and sulfuric acid.

While the complete analysis for solid and liquid

particulates is described in sequence in the

following sections, not all steps are necessarily

applied to every sample.

Where organics are not expected to be a

significant portion of the combined probe and

impinger catch (greater than 5 mg or 5 percent),
5.1-50

the organic extraction procedure found in

Sections 3.7.2 and 3.7.3 may be eliminated, and

the probe and impinger catch analysis begun

directly with Section 3.7.4.

If the sampled gases contained SO2 in

concentrations less than 5 ppm, the analyses of

combined probe and impinger catch for acid and

sulfate found in Sections 3.7.6, 3.7.7, and 3.7.8

may be eliminated.

Finally, if the filter has collected more than

10 mg, it must be analyzed for acid and sulfate.

Filter preparation for subsequent analysis is

found in Section 3.7.5.

3.7.1 Filter Catch

Leave the contents in the shipping

container or transfer the filter and any

loose particulate from the sample

container to a tared glass weighing dish.

Desiccate for 24 hours in a desiccator

containing anhydrous calcium sulfate.

Weigh to a constant weight and report the

results to the nearest 0.1 mg. For this

method, the term "constant weight" means a
5.1-51

difference of no more than 0.5 mg or 1

percent of total weight less tare weight,

whichever is greater, between two

consecutive weighings, with no less than 6

hours of desiccation time between

weighings.

Alternatively, the sample may be ovendried at 105oC (220oF) for 2 to 3 hours,

cooled in a desiccator, and weighed to a

constant weight.

3.7.2 Probe and Impinger Catch - Insoluble

Particulates

If organic extraction is to be performed,

first filter the sample through a tared

fiberglass filter dried at 105oC. This

prevents any insolubles from interfering

with the organic extraction. Rinse the

filter and insoluble catch using

dichloromethane and combine this rinse

with the dichloromethane extract described

in the next section. Dry the fiberglass

filter at 105oC (220oF) and report as

"Insoluble Particulate".
5.1-52

3.7.3 Probe and Impinger Catch - Organic

Extraction

Transfer the aqueous filtrate from Section

3.7.2 to a separatory funnel.

Extract the aqueous catch five times with

25 ml portions of dichloromethane. Each

time, extract for 30 seconds with vigorous

shaking, then allow the layers to

separate. This may take up to 15 minutes

due to emulsion formation. When using

dichloromethane, use gloves and work in a

hood.

Drain the dichloromethane layers into a

tared 150 ml beaker. Save the aqueous

layer for use in Section 3.7.4. Evaporate

the organic extract under a stream of

clean filtered air at room temperature in

a hood. Place in a desiccator overnight.

Weigh the extract residue to the nearest

0.1 mg. Record the gross and tared

weights and report the net weight as

"Solvent Extract".
5.1-53

3.7.4 Probe and Impinger Catch - Soluble Residue

Quantitatively transfer the aqueous catch

to a beaker. If solvent extraction has

been performed, warm the sample on a hot

plate, being careful to prevent any

residual solvent from causing the sample

to "bump". Use a ribbed watch glass to

cover the beaker. This will allow

scrubbing of the beaker walls and protect

the sample from contamination.

Concentrate the sample to about 50 ml.

Quantitatively transfer the aqueous

concentrate to a tared 150 ml beaker and

evaporate in an oven at 105oC (220oF) to

dryness.

Weigh the residue to constant weight, to

the nearest 0.1 mg, and record the weight.

Desiccate the sample for 6 hours and

reweigh the sample. Repeat until the

weight changes less than 0.5 mg between

weighings.

Add the insoluble and soluble weights from

Sections 3.7.2 and 3.7.4 and report as
5.1-54

"Impinger Catch". Do not include the

solvent extract.

3.7.5 Filter Catch - Preparation for Acid and

Sulfate Analysis

Filters are analyzed for acid and sulfate

if the filter catch is greater than 10 mg.

The whole filter is processed. Cut the

filter into pieces into a 400 ml beaker,

being careful not to lose any sample.

Submerge it in distilled water. Add

5.0 ml of approximately 0.1N HCl and soak

the filter at least four hours, with

occasional stirring. Recover the liquid

quantitatively by vacuum filtration using

a 0.45 micron cellulose ester paper and

rinsing the sample filter at least three

times with water. Process a blank filter

at the same time following the same

procedure.

3.7.6 Probe and Impinger Catch - Preparation for

Acid and Sulfate Analysis

Add distilled water to the 150 ml beaker

containing the residue from Section 3.7.4
5.1-55

until the beaker is three-fourths full.

Cover the beaker and allow it to soak at

least four hours.

3.7.7 Acid Analysis

Add several drops of methyle orange to

each extraction solution from Sections

3.7.5 and 3.7.6, including the blank

filter extract.

Titrate each solution with standardized

0.1N sodium hydroxide solution to a straw

yellow colored end point (pH 4.2). Record

the volumes to the nearest 0.02 ml.

Alternately, use an automatic titrator

known to be accurate.

Filter the aqueous catch through a 0.45

micron cellulose ester paper to remove any

insolubles, and quantitatively recover

this extract using at least three rinsings

with water.
5.1-56

3.7.8 Sulfate Analysis

Adjust each titrated solution from Section

3.7.7, to approximately pH 7 and add 2 ml

of concentrated HCl. Place each beaker on

the hot plate, add a stirring rod, and

cover with a ribbed watch glass. Heat

until the solution is nearly boiling.

While stirring, slowly add 15 ml of 10

percent barium chloride solution. Let the

precipitate settle. Add a ml of BaCl2; if

more precipitate forms, keep adding BaCl2

until no more precipitate is produced.

Allow the precipitate to digest several

hours on the steam bath.

Quantitatively filter through a properly

prepared Gooch crucible (see Section 3.1.4

e; use safety precaution while handling

the asbestos for the mat). Rinse the mat

thoroughly with hot distilled water and

test for chloride in the rinse, using

silver nitrate solution. If chloride is

absent, place the crucible in the furnace

and heat at 900oC (1650oF) for one hour.

Cool and place the crucible in a
5.1-57

desiccator for at least 6 hours. Weigh

until constant weight is reached (6 hours

desiccation between weighings). Record to

the nearest 0.1 mg.

3.8 Calculations and Reporting

Carry out calculations, retaining at least one

decimal figure more than that of the acquired

data. Round off figures after the final

calculation. Summarize the data to be reported

to source testers using the following listing:

Total Impinger Volume, ml (g)

Impinger Gain, ml (g)

Total Impinger Volume Incl. Washings, ml (g)

Silica Gel Gain, g

Organic Extract, mg

Insoluble Residue, mg

Soluble, or Total, Residue, mg

Acid, as H2SO4·2H2O, mg

Sulfate, as H2SO4·2H2O, mg

Filter Catch, mg

Acid, as H2SO4·2H2O, mg

Sulfate, as H2SO4·2H2O, mg
5.1-58

Calculate the above measurements as follows:

Wf - Wt

where:

Wf = Constant weight measurement of the

the sample plus container, to 0.1

mg

Wt = Tare weight of the sample

container, to 0.1 mg

Acid, as

134.11

H2SO4.2H2O= VxNx ------ x AF

2

where:

V = Volume of sample titration (minus

blank, where required), ml

N = Normality of NaOH used

134.11

------ = Equivalent weight of H2SO4·2H2O

2
5.1-59

AF = Aliquot factor (sample volume/

analysis volume), normally 1

Sulfate,

as,

134.11

H2SO4·2H2O = (Wf - Wt) x ------ x AF

233.43

Where:

Wf = Constant weight of barium sulfate

precipitate plus crucible to 0.1

mg

Wt = Tare weight of crucible, to 0.1 mg

134.11 H2SO4·2H2O

------ = Molecular weight of -----

233.43 BaSO4

3.9 Calibrations

3.9.1 Balance Calibration

Calibrate the analytical balance using NBS

traceable weights. Retain calibration

records for each balance. These records

are usually furnished yearly by a

professional service providing the
5.1-60

calibrations. Check at least monthly for

balance accuracy, using NBS traceable

weights.

3.9.2 Furnace Check

Check the furnace and oven operating

temperatures in accordance with the

manufacturer's instruction manuals.

3.9.3 Sodium Hydroxide Standardization

Standardize the sodium hydroxide using the

following procedure:

Dry crushed primary grade potassium acid

phthalate (KHP) in an oven at 105oC

(220oF) for two hours. Cool to room

temperature in a desiccator. Weigh 0.95 g

+ 0.05 g of KHP, to the nearest 0.1 mg,

into an Erlenmeyer flask. Dissolve in

70 ml of water and add 2-4 drops of

phenolphthalein indicator. Titrate

quickly to a faint pink end point using

0.1N NaOH. Repeat this titration using

another portion of KHP. Titrate duplicate

70 ml blanks of water using the above
5.1-61

procedure, and average the results.

Replicate blanks must agree within

0.05 ml. Calculate the normality for each

KHP aliquot as follows:

mg KHP/203.44

N = -----------

(ml std-avg. blank)

Values must agree within 0.5 percent.

Average the results and report to four

significant figures. Label the sodium

hydroxide with the normality, date of

standardization, and reference to the

data.

3.9.4 Autotitrator

Calibrate the pH meter of the autotitrator

using pH 4 and pH 7 buffers and following

the manufacturer's instructions.
5.1-62

METHOD 5.1

DETERMINATION OF PARTICULATE MATTER EMISSIONS FROM

STATIONARY SOURCES USING A WET IMPINGEMENT TRAIN

Section 4 of 4

4. Engineering Calculations and Reporting

4.1 Calculations

Carry out calculations, retaining at least one

extra decimal figure beyond that of the acquired

data. Round off figures after the final

calculation. Other forms of the equations may be

used as long as they give equivalent results.

See Figure 5.1-4, 5.1-5 and 5.1-6.
5.1 - 63
5.1 - 64
5.1 - 65
5.1 - 66
5.1 - 67
5.1 - 68