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FEDERAL

REGISTER

VOLUME 36 - NUMBER 84

Friday, April 30, 1971 * Washington, D.C.

PART Il

ENVIRONMENTAL

PROTECTION AGENCY

National Primary and Secondary

Ambient Air Quality Standards

No. 8.--Pt. r -1
RULES AND REGULATIONS

Title 42-PUBLIC HEALTH

Chapter IV-Environmental Protection

Agency

PART 41 O-NATIONAL PRIMARY AND

SECONDARY AMBIENT AIR QUALITY STANDARDS

Notices of proposed Irule-making published in the FEDERAL REGISTER on January 30, 1971 (36 F.R. 1502) and

MVarch 26, 1971 (36 F.R. 5867) set forth

regulations prescribing national primary

and secondary ambient air quality

standards proposed for adoption as Part

410 of 42 CFR. Interested persons were

afforded an opportunity to participate

in the rule-making by submitting comments. Following review of the proposed

standards and consideration of the comments, the standards have been revised

as described below and are being

promulgated today.

National primary ambient air quality

standards are those which, in the judgment of the Administrator, based on the

air quality criteria -and allowing an adequate margin of safety, are requisite to

protect the public health.

National secondary ambient air quality

standards are those which, in the judgment of the Administrator, based on the

air quality criteria, are requisite to protect the public welfare from any known

or anticipated adverse effects associated

with the presence of air pollutants in

the ambient air.

The comments submitted to the Environmental Protection Agency reflect

divergences of opinion among interested

and informed persons as to the proper

interpretation of available data on the

public health and welfare effects of the

six pollutants for which national ambient air quality standards are being established. A number of comments question the feasibility of implementing the

proposed standards. Because the Clean

Air Act, as amended, does not permit any

factors other than health to be taken

into account in setting -the primary

standards, no revisions were made on

this basis. In reviewing the proposed

standards, the Environmental Protection

Agency limited its consideration to comments concerning the validity of the

scientific basis of the standards.

Current scientific, knowledge of the

health and welfare hazards of these air

pollutants is imperfect. To increase and

improve this knowledge, the Environmental Protection Agency will continue

to conduct and support relevant research. At the same time, the need for

increased knowledge of the health and

welfare effects of air pollution cannot

justify failure to take action based on

knowledge presently available. The

Clean Air Act, as amended, requires

promulgation at this time of national

standards for six air pollutants on the

basis of available data set forth in air

quality criteria documents. Thus, the

Administrator is required to make judgments as to the proper interpretation of

presently available data and to establish

national primary standards which include an adequate margin of safety to

protect human health. Where the validity of available research data has been

questioned, but not wholly refuted, the

Administrator has in each case promulgated a national primary standard which

includes a margin of safety adequate to

protect the public health from adverse

effects suggested by the available data.

The national primary standard for

carbon monoxide, proposed on January

30, 1971, was based on evidence that low

levels of carboxyhemoglobin in human

blood may be associated with impairment

of ability to discriminate time intervals.

This evidence is reflected in "Air Quality

Criteria for Carbon Monoxide" (35 FR.

4768). In the comments, serious questions

were raised about the soundness of this

evidence. Extensive consideration was

given to this matter. The conclusions

reached were that the evidence regarding

impaired time-interval discrimination

had not been' refuted and that a less restrictive national standard for carbon

monoxide would therefore not provide

the margin of safety which may be

needed to protect the health of persons

especially sensitive to the effects of elevated carboxyhemoglobin levels. The

only change made in the national standards for carbon monoxide was a modification of the 1-hour value. The revised

standard affords protection from the

same low levels of blood carboxyhemoglobin as a result of short-term exposure. The national standards for carbon

monoxide,, as set forth below, are intended to protect against the occurrence

of carboxyhemoglobin levels above 2 percent. It is the Administrator's judgment

that attainment of the national standards for carbon monoxide will provide

an adequate safety margin for protection of public health and will protect'

against known and anticipated adverse

effects on public welfare.

National standards for photochemical

oxidants have also been revised. The revised national primary standard of 160

pg./m?. (0.08 p.pm.) is based on evidence

of increased frequency of asthma attacks in some asthmatic subjects on days

when estimated hourly average concentrations of photochemical oxidant

reached 200 pg./m? (0.10 p.pm.). A number of comments raised serious questions

about the validity of data used to suggest impairment of athletic performance

at lower oxidant concentrations. The

revised primary standard includes a margin of safety which is substantially below the most likely threshold level suggested by this data. It is the Administrator's judgment that a primary standard

of 160 pg./m? (0.08 p.pm.) as a 1-hour

average will provide an adequate safety

margin for protection of public health

and will protect against known and anticipated adverse effects on public

welfare.

National standards for hydrocarbons

have been revised to make these standards consistent with the above modifications of the national standard for photochemical oxidants. Hydrocarbons are

a precursor of photochemical oxidants.

The sole purpose of prescribing. a hydrocarbon standard is to control photochem- ical oxidants. Accordingly, the abovedescribed revisions of the national

standards for photochemical oxidants

necessitated a corresponding revision of

the hydrocarbon standards.

National standards for nitrogen dionide have been revised to eliminate the

proposed 24-hour average value. No adverse effects on public health or welfare

have been associated with short-term

exposure to nitrogen dioxide at levels

which have been observed to occur in the

ambient air. Attainment of the annual

average will, in the Administrator's judgment, provide an adequate safety margin for protection of public health and

will protectagainst known and anticipated adverse effects on public welfare.

Appendices A through F, which describe measurement methods, have been

revised to clarify many technical points.

As revised, each appendix describes a

complete reference method for evaluating the ambient concentration of a pollutant for which national ambient air

qualIV standards are being established.

Nine months after the date of publication of this notice, the States are required to submit to the Administrator,

in accordance with section 110 of the

Act, implementation plans for the attainment and maintenance of the national primary and secondary standards

specified in this part. Requirements for

the preparation, adoption, and submittal

of Implementation plans were published

by the Administrator, as proposed rulemaking, in the FEDrnRAL REoisrn on April

7, 1971 (36 F.R. 6680).

In consideration of the foregoing and

in accordance with the statements In the

notice of proposed rule-making, the national primary and secondary ambient

air quality standards, Part 410, are hereby promulgated effective upon publication.

Dated: April 28, 1971.

WILLiAm D. RUOIMLSUAUS,

Administrator.

A new Part 410 is added to Chapter IV,

Title 42, Code of Federal Regulations as

follows:

Sec.

410,1 Definition,.

410.2 Scope. 410.3 Reference condition5.

410.41 National primary ambient air quality standards for sulfur oxides (sulfur

dioxide).

410.5 National secondary ambient air qtality standards for sulfur oxide

(sulfur dioxide).

410.6 National primary ambient air quality standards for particulate matter.

410.7 National secondary ambient air qual- ity standards for partloulate

matter.

410.8 National primary and secondary am- bient air quality standards for

carbon monoxide.

410.9 National primary and secondary am- bleat air quality standard for

photochemical oxidants.

410.10 National primary and secondary ambient air quality standard for

hydrocarbons.

410.11 National primary and secondary am- blent air quality standard for

nitrogen diodde %

FEDERAL REGISTER, VOL. 36, NO. 84-FRIDAY, APRIL 30, 1971
RULES AND REGULATIONS

Appendix A-Peference Method for the Determination of Sulfur Dioxide in

the Atmosphere (PararosanllIne

Method).

Appendix B--eference Method for the Determination of Suspended Particulates in the Atmosphere (High Volnime Method).

Appendix C-Reference Metl-nd for the Continuous leasurcmet of Carbon

monoxide in the Atmosphere (Nondispersive Infrared Spectrometry).

Appendix D-Reference Method for the

Measurement of Photochemical

Oxidants Corrected for Interferences Due to Nitrogen Oxide and

Sulfur Dioxide.

Appendix F-Reference Method for the Determination of Hydrocarbons Corrected for Methane.

Appendix F-Reference Method for the Determination of Nitrogen Dioxide

(24 -Hour Sampling Method).

AuTron=: The provisions of this Part

410 issued under sec. 4, Public Law 91-004,

Stat. 1679. -

§ 410.1 Definitions.

(a) As used in this part, all terms not

defined herein shall have the meaning

given them by the Act.

(b) "Act" means the Clean Air Act, as

amended (Public Law-91-604; 84 Stat.

1676).

(c) "Agency"- means the Environmental Protection Agency.

(d) "Administrator" means the Administrator of the Environmental Protection Agency.

(e) "Ambient air" means that portion

of the atmosphere, external to buildings,

to which the general public has access.

(f) "Reference method" means a

method of sampling and analyzing for

an air pollutant, as described in an appendix to this part.

(g) "Equivalent method" means any

method of sampling and analyzing for

an air pollutant which can be demonstrated to the Administrator's satisfaction to have a consistent relationship to

the reference method.

§ 410.2 Scope.

(a) National primary and secondary

ambient air quality standards under section 109 of the Act are set forth in this

part.

(b) National primary ambient air

quality standards define levels of air

quality which the Administrator judges

are necessary, with an adequate margin

of safety, to protect the public health.

National secondary ambient air quality

standards define levels of air quality

which the Administrator judges necessary-to protect the public welfare from

any known or anticipated adverse effects

of a pollutant. Such standards are subject to revision, and additional primary

and secondary standards may be promulgated as the Administrator deems neces- sary -to protect the public health and

welfare.

(c) The promulgation of national

primary and secondary ambient air qtlality standards shall not be considered in

any manner to allow significant deterioration of existing air quality in any portioui of any State.

(d) The proposal, promulgation, or revision of national primary and secondary ambient air quality standards shall

not prohibit any State from establlshing

ambient air quality standards for that

State or any portion thereof which are

more stringent than the national

standards.

§ 410.3 Reference conditions.

All measurements of air quality are

corrected to a reference temperature of

25* C. and to a reference pressure of 7GO

millimeters of mercury (1,013.2 millibars).

§ 410.4 National primary ambient air

quality standards for sulfur oxides

(sulfur dioxide).

The national primary ambient air

quality standards for sulfur oxides,

measured as sulfur dioxide by the reference method described in Appendix A to

this part, or by an equivalent method, are:

(a) 80 micrograms per cubic meter

(0.03 p.p.m.)-annual arithmetic mean. (b) 365 micrograms per cubic meter

(0.14 p.p.m.)-Maximum 24-hour concentration not to be exceeded more than

once per year.

§ 410.5 National secondary ambient air

quality standards for sulfur oxides

(sulfur dioxide).

The national secondary ambient air

quality standards for sulfur oxides,

measured as sulfur dioxide by the reference method described in Appendix A to

this part, or by an equivalent method, are:

(a) 60 micrograms per cubic meter

(0.02 p.p.m.)-annual arithmetic mean. (b) 260 micrograms per cubic meter

(0.1. p.p.m.)-maximum 24-hour concentration not to be exceeded more than once per year, as a guide to be uced in

assessing implementation plans to achieve

the annual standard.

(W) 1,300 micrograms per culba meter

(0.5 p.pam.)-maximum 3-hour concentration not to be exceeded more than

once per year.

§ 410.6 National primary ambient air

quality standards for particulate

matter.

The national primary ambient air

quality standards for particulate matter,

measured by the reference method described in Appendix B to this part, or by an equivalent method, are: (a) 75 micrograms per cubic meterannualgeometrlc mean. (b) 260 micrograms per cubic metermaximum 24-hour concentration not to

be exceeded more than once per year.

§ 410.7 National secondary ambient air

quality standards for particulate

matter.

The national secondary ambient air

quality standards for particulate matter,

measured by the reference method described in Appendix B to this part, or by

an equivalent method, are: (a) 60 micrograms per cubic meterannual geometric mean, as a guide to be

usedin assessing implementation plans to

achieve the 24-hour standard.

(b) 150 mlcrorams per cubic metermaximum 24-hour concentration not to

be exceeded more than once per yea -.

410.3 National primary and secondary

nmbient air quality standards for carbon monoxide.

The national primary and secondary

ambient air quality standards for carbon

monoxide, meaured by the reference

method dczcrlbed in Appendix C to this

part, or by an equivalent method, are: (a) 10 millIgrams per cubic meter (9

p.p.m.)-maximum 8-hour concentration not to be exceeded more than once per year.

(b) 40 millI ms per cub c meter (35

p.px.)-maximum 1-hour concentration not to be exceeded more than once

per year.

§ 410.9 National primary and secondary

ambient air quality standards for

photochemical oxidants.

The national primary and secondary

ambient air quality standard for photochemical oxidants, measured and corrected for interferences due to nitrogen

oxides and sulfur dioxide by the reference

method decribed in Appendix D to this

part, or by an equivalent method, is: 160

micro-rams per cubic meter (0.03

pp.m.)-maximum 1-hour concentraion not to be exceeded more than once

per year.

§ 410.10 National primary and secondary ambient air quality standard for

hydrocarbons.

The hydrocarbons standard is for use

as a guide in deviinfg implementation

plans to achieve oxidant standards.

The national primary and secondary

ambient air quality standard for hydrocarbons, measwured and corrected for

methane by the reference method described in Appendix E to this part, or by

an equivalent method, is: 160 mlcrograms

per cubic meter (0.24 p.pa.)-maximum

3-hour concentration (6 to 9 a.m.) not to

be exceeded more than once per year.

§ 410.11 National primary and secondary ambient air quality standard for

nitrogen dioxide.

The national primary and secondary

ambient air quality standard for nitrogen

dioxide, measured by the reference

method dezcrlbed in Appendix F to this

part, or by an equivJent method, is: 100

mlcro7rams per cubic meter (0.05

p.pm.)-annual arithmetic mea l.

Ar-.oz'ia (P na.o2.tzzax 2lcr-xcn)

1. Prlfeipac cra AV!fcaTbZftY. 1.1 Sulfur dtddo 13 ab:arbsi from air in a colutfon of

pot"-'um tct-cblo oarcurato (TC21). A

dlccl .u ftom.rta comylcz.,which rersliz oxidation by tho o..Tyn In the air, is

formcs (1. 2). Onc3 formci, this complex is

stablo to ctr oag o z 2nt3 (e., ozone, ozlds

oef nitrcgen). 'lbs comp'cz t; rsactcd rlth

pararc :anlllno and formnldehydo to form Intenaly colorcd parare:nillno methyl ualfontc acld (3). 'lbs abz7,rbsnca of the zzlutVon ia measured rc,7ctrofhotomscticcily.

1.2 The matheId L7, cppllcb1e to the m=---

urement of sultr diozfdo in amblent air

uzlngicmpllnz pcrlc., up to 21 houro.

FEDERAL REGISTER, VOL 36, NO. 04-FRIDAY, AFMIL 30, 1971
8188

2. Range and Sensitivity. 2.1 Concentrations of sulfur dioxide in the range of 25 to 1,050 pg/m. (0.01 to 0.40 p.p.m.) can be meas- ured under the conditions given. One can measure concentrations below 25 gg./m.3 by

sampling larger volumes of air, but only if

the absorption efficiency of the particular system is first determined. Higher concentra- tions can be analyzed by using smaller gas

samples,, a larger collection volume, or a suitable aliquot of the collected sample. Beer's

Law is followed through the working range

from 0.03 to 1.0 absorbance units (0.8 to 27

pg. of sulfite ion in 25 nil. final solution computed as S02).

2.2 The lower limit of detection of sulfur

dioxide in 10 ml. TOM is 0.75 pg. (based on

twice the standard deviation) representing a concentration of 25 Ag./m.aO 2 (0.01 p.p.m.)

in an air sample of 30 liters.

3. Interferences. 3.1 The effects 9f the

principal known interferences have been

minimized or eliminated. Interferences by

oxides of nitrogen are eliminated by sulfamic

acid (4, 5), ozone by time-delay (6), and

heavy metals by EDTA (ethylenediaminetetroacetic acid, disodium salt) and phosphoric acid (4, 6,). At least 60 pg. Fe (III),

10 pg. Afn(II), and 10 /pg. Cr(III) in 10 ml.

absorbing reagent can be tolerated in the

procedure. No significant interference was

found with 10 pg. CU.(Il) and 22 pg. V(V).

.4. Precision, Accuracy, and Stability. 4.1

Relative standard deviation at the 95 percent

confidence level is 4.6 percent for the analytical procedure using standard samples. (5)

4.2 After sample collection the solutions are relatively stable. At 22 ° C. losses of sulfur

dioxide occur at the rate of 1 percent per

day. When samples are stored at 5° C. for

30 days, no detectable losses of sulfur dioxide occur. The presence of EDTA enhances

the stability of S02 in solution, and the rate

of decay is independent of the concentration

of SO2. (7)

5. Apparatus.

5.1 Sampling.

5.1.1 Absorber. Absorbers normally used

in air pollution sampling are acceptable for

concentrations above 25 pg./m.; (0.01 p.p.m.).

An all-glass midget impinger, as shown in

Figure Al, is recommended for 30-minute and

1-hour samples.

For 24-hour sampling, assemble an absorber from the following parts:

Polypropylene 2-port tube closures, special

manufacture (available from Bel-Art Products, Pequannock, N.J.).

Glass impingers, 6 mm. tubing, 6 inches

long, one end drawn to small diameter such

that No. 79 jewelers will pass through, but

No. 78 Jewelers will not. (Other end fire

polished.)

Polypropylene tubes, 164 by 32 mm. Nalgene or equal).

5.1.2 Pump. Capable of maintaining an

air pressure differential greater than 0.7 at- mosphere at the desired flow rate.

5.1.3 Air Flowmeter or Critical Orifice.

A calibrated rotameter or critical orifice capable of measuring air flow within ___2 per- cent. For 30-minute sampling, a 22-gauge

hypodermic needle 1 inch long may be used as a critical orifice to give a flow of about 1

liter/minute. For 1-hour sampling, a 23-

gauge hypodermic needle five-eighths of an inch long may be used as a critical orifice to give a flow of about 0.5 liter/minute. For

21 .hour sampling, a 27-gauge hypodermic

needle three-eighths of an inch long may be

used to give a flow of about 0.2 liter/minute.

Use a membrane filter to protect the needle

(Figure Ala).

6.2 Analysis.

5.2.1 Spectrophotometer. Suitable for measurement of absorbance at 548 rinm. with an effective spectral band width of less than

16 nm. Reagent blank problems may occur with spectrophotometers having greater

RULES AND REGULATIONS

spectral band width. The wavelength calibration of the instrument should be verified.

If transmittance is measured, this can be

converted to absorbance:

A=ogi0 (1/T)

6. Reagents.

6.1 Sampling.

6.1.1 Distilled water. Must be free from

oxidants.

6.1.2 Absorbing Reagent [0.04 M Potassium Tetiachloromercurate (TOM) ]. Dissolve

10.86 g. mercuric chloride, 0.066 g. EDTA

(thylenediaminetetraacetic acid, disodoumn

salt), and 6.0 g. potassium chloride in water and bring to mark in a 1,000-mi. volumetric

flask. (Caution: highly poisonous. If spilled on skin, flush off with water immediately).

The pH of this reagent should be approximately 4.0, but it has been shown that there

is no appreciable difference in collection

efficiency over the range of pH 5 to pH 3.(7)

The absorbing reagent is normally stable for

6 months. If a precipitate forms, discard the

reagent.

5.2 Analysis.

6.2.1 Sulfamic Acid (0.6 percent), Dissolve 0.6 g. sulfamic acid in 100 ml. distilled

water. Prepare fresh daily.

6.2.2 Formaldehyde (0.2 percent). Dilute

5 ml. formaldehyde solution (36-38 percent)

to 1,000 ml. with distilled water. Prepare

daily.

6.2.3 Stock Iodine Solution (01 N). Place

12.7 g. iodine in a 250-ml. beaker; add 40 g.

potassium iodide and 25 ml. water. Stir until

all is dissolved, then dilute to 1,000 mil. with

distilled water.

6.2.4 Iodine Solution (0.01 N). Prepare

approximately 0,01 I iodine solution by dlluting 50 m. of stok solution to G00 ml.

with distilled water.

6.2.5 Starch Indicator Solution. Trlturato

0.4 g. soluble starch and 0.002 g. mercuric

iodide (preservative) with a little water, and

add the paste slowly to 200 ml. boiling water. Continue boiling until the solution Ii clear

cool, and transfer to a glagu-stoppered bottle.

6.2.6 Stock Sodium Thiosullato Solution

(0.1 N). Prepare a stock solution by dissolving

25 g. sodium thiosulfato (Na 0.5Qv6O) In

1,000 ml. freshly boiled, cooled, distilled water and add 0.1 g. sodium carbonato to the solution. Allow the solution to stand 1 day beforo

standardizing. To standardize, accurately

weigh, to the nearest 0.1 mg., 1.5 g. primary

standard potassium iodato dried at 180 o 0.

and dilute to volume In a 500-ml. volumotrlo

flask. To a 500-ml. iodine flash, pipot 50 ml,

of Iodate solution. Add 2 g. potassium iodide

and 10 mi. of 1 N hydrochloric acid. Stopper

the flask. After 5 minutes, titrato with stock

thiosulfato solution to a pale yellow. Add 5

ml. starch indicator solution and continue

the titration until the blue color disappears,

Calculate the normality of the stook

solution:

W

X=-Y2.80

M

N=Normality of stock thiosulfato Colution.

I=Volume of thiosulfato required, ml.

W=Weight of potassium Iodate, grama.

I

103 (conversion of g. to mg.) X0.1 (fraction odato used) 35.67 (equivalent weight of potassium lodate)

6.2.7 Sodium Thiosulfate Titrant (0.01 N).

Dilute 100 ml. of the stock thlosulfate solution to 1,000 ml. with freshly boiled distilled

water.

Ndrmality=Normality of stock solution

X0.100.

6.2.8 Standardize Sulfite Solution for

Preparation of Working Sulfite-TOM Solution. Dissolve 0.3 g. sodium metabisulfite

(NaSO,) or 0.40 g. sodium sulfite (NaSO,)

in 500 ml. of recently boiled, cooled, distilled

water. (Sulfite solution is unstable; It is

therefore Important to use water of the highest purity to minimize this instability.) This

solution contains the equivalent of 320 to 400

Ag./ml. of SO. The actual concentration of

the solution is determined by adding excess iodine and back-titrating with standard

sodium thlosulfate solution. To back-titrate,

pipet 50 ml. of the 0.01 N iodine into each of

two 500-mi. iodine flasks (A and B). To flask

A (blank) add 25 mi. distilled water, and to flask B (sample) pipet 25 mi. sulfite solution.

Stopper the flasks and allow to react for 5

minutes. Prepare the working sulfite-TCM

SolutioA (6.2.9) at the same time iodine

solution is added to the flasks. By means of

a buret containing standardized 0.01 N thiosulfate, titrate each flask in turn to a pale

yellow. Then add 5 m. starch solution and

continue the titration until the blue color

disappears.

6.2.9 Working Sulflte-TOM Solution. Pipet

accurately 2 ml. of the standard solution into

a 100 ml volumetric flask and bring to mark

with 0.04 Mf TOM Calculate the concentration of sulfur dioxide in the working solution:

(A - B) (N) (32.000) 25X0.02

25

A=Volume thiosulfate for blank, niL

B=Volume thiosulfate for sample, nmL

N=Normallty of thiosulfato titrant,

32,000=Milllequivalent wt. of SO,, pg,.

25=Volume standard sulfito solution,

ml.

0.02=Dilution factor.

This solution is stable for 30 daya If kept at

50 C. (refrigerator). If not kept at 5

° 0,,

prepare daily.

6.2.10 Purified Pararosantline Stock SofutIon (0.2 percent nominal).

6.2.10.1 Dye Specflcations. The pararosanillne dye must meet the following performance specifications: (1) the dye must

have a wavelength of maximum absorbanco

at 540 nm. when assayed in a bufered volution of 0.1 At sodium acetate-acetlo acid,, (2)

the ibsorbanco of the reagent blank, which Is

temperature-sgnsitivo (0.015 abeorbance

unit/°C), should not exceed 0.170 ab."orbanco

unit at 22" 0. with a 1-oem, optical path

length, when the blank Is prepared according to the prescribed analytical procedure

and to the specified concentration of the dye:

(3) the calibration curve (Section 0,2.1)

should have a slope of 0.030±0.002 a1kurb- anco units/g. SOO at thl path length when

the dye is pure and the sulfite solution Is

properly standardized.

6.2.10.2 Preparation of Stock Solution. A

specially purified (99-100 percent pure) to- lutlon of pararosanilino, which meets the

above specifications, Is commercially available In the required 0.20 percent concen- tration (Harleco*). Alternatively, the dye

may be purified, a stool solution prepared

and then assayed according to the procedure of Scaringelli, ot al. (4)

6.2.11 Pararosaniline Reagent. To a 250-

ml. volumetric flask, add 20 ml. stock pararoaniline solution. Add an additional 0,2

ml. stock solution for each percent thle stocll

*Hartmen-Leddon, 60th and Woodland

Avenue, Philadelphia, PA 19143.

FEDERAL REGISTERr VOL 36, NO. 84--FRIDAY, APRIL 30, 1971
RULES AND REGULATIONS

assays below 100 percent. Then add 25 ml.

3 M phosphoric acid and dilute to volume

with distilled water. This reagent Is stable

for at least 9 months.

7. Procedure.

7.1 Sampling. Procedures are described

for short-term (30 minutes and 1 hour) and

for long-term (24 hours) sampling. One can select different combinations of sampling rate and time to meet special needs. Sample

volumes should be adjusted, so that linearity

Is maintained between absorbance and con- centration over the dynamic range.

7.1.1 30-Minute and 1-Hour Samplings.

Insert a midget impinger into the sampling

system, Figure Al. Add 10 ml. TCM solution to the impinger. Collect sample at 1 liter/

minute for 30 minutes, or at 0.5 liter/minute

for 1 hour. using either a rotameter, as shown. in Figure Al, or a critical orifice, as shown in Figure Ala, to control flow. Shield

the absorbing reagent from direct sunlight

during and after sampling by covering the

impinger with aluminum foil, to prevent

-- deterioration. Determine the volume of air

sampled by multiplying the flow rate by the

time in minutes and record the atmos- pheric pressure and temperature. Remove

and stopper the impinger. If the sample must be stored for more than a day before

analysis, keep it at 5' C. in-a refrigerator (see42).

7.12 24-Hour Sampling. Place 50 ml.

TCM solution in a large absorber and collect the sample at 0.2 liter/minute for 24

hours from midnight to midnight. Make sure no entrainment of solution results with the

impinger. During collection and storage pro- tect from direct sunlight. Determine the

total air volume by multiplying the air flow rate by the time in minutes. The correction

of 24-hour measurements for temperature

and pressure is extremely difficult and Is not ordinarily done. However, the accuracy of

the measurement will be improved if meaningful corrections can be applied. If storage

is necessary, refrigerate at 5' C. (see 4.2).

7.2 Analysis.

7.2.1 Sample Preparation. After collection,

if a precipitate is observed in the sample,

remove it by centrifugation.

7.2.1.1 30-Minute and 1-Hour Samples.

Transfer the sample quantitatively to a 25-

ml. volumetric flask; use about'S ml. distilled water for rinsing. Delay analyses for 20 minutes to allow any ozone to decompose.

7.2.1.2 24-Hour Sample. Dilute the entire

sample to 50 ml. with absorbing solution.

Pipet 5 ml- of the sample into a 25-ml.

volumetric flask for chemical analyses. Bring

volume to 10 ml. with absorbing reagent.

Delay analyses for 20 minutes to allow any ozone to decompose.

7.2.2 Determination. For each set of determinations prepare a reagent blank by adding 10 ml. unexposed TCM solution to a 25-

ml. volumetric flask. Prepare a control solution by adding 2 ml. of working sulflte-TOM

solution and 8 ml. TOM solution to a 25-mi.

volumetric flask. To each flask containing either sample, control solution, or reagent

blank, add 1 ml. 0.6 percent sulfamlo

acid and allow to react 10 minutes to destroy the nitrite from oxides of nitrogen.

Accurately pipet in 2 ml. 0.2 percent

formaldehyde solution, then 5 ml. par- arosaniline solution. Start a laboratory

timer that has been set for 30 minutes. Bring

all flasks to volume with freshly boiled and

cooled distilled water and mix thoroughly.

After 30 minutes and before 60 minutes, determine the absorbances of the sample (de- note as A), reagent blank (denote as Ao) and

the control solution at 548 nm. using 1-cm.

optical path length cells. Use distilled water, not the reagent blank, as the reference.

(NoTE! This is important because of the color

sensitivity of the reagent blank to tempera- ture changes which can be induced in the

cell compartment of a spectrophotometcr.)

Do not allow the colored solutlon to stand

in the absorbance cells, becauce a film of dye

may be deposited. Clean cells with alcohol

after use. If the temperature of the detcrmlnations does not differ by more than 2" C.

from the calibration temperature (8-). the

reagent blank should be within 0.03 abzo rbance unit of the y-lntercept of the calibration curve (8.2). If the reagent blank differs

by more than 0.03 abzorbanco unit from that

found In the calibration curve, prepare a new

curve.

7.2.3 Absorbance Range. If the absorbanco

of the sample solution ranges between 1.0

and 2.0, the sample can be diluted 1:1 with a portion of the reagent blank and read

within a few minutes. Solutions with higher

absorbance can be diluted up to risfold with

the reagent blank In order to obtain ontc ao

readings within 10 percent of the true absorbance value.

8. Calibration and EBfIlencies.

8.1 Flowmctcrs and Hypodermic Zicedle.

Calibrate flowmeters and hypodermlo nee- dle (8) against a calibrated wct test meter.

8.2 Calibration Curres.

8.2.1 Procedure with SuWfIte Solution. Ac.

curately pipet' graduated amounts of the

'Worklng'sullte-TCM rolution (0.2.9) (such s 0, 0.5, 1, 2, 3, and 4 ml.) Into a cries of

25-mi. Tolumetric flasl;. Add sufficent TCOM

solution to each flask to bring the volume to

approximately 10 ml. Then add the remaining

reagents as described In 7.2.2. For mwximum

precision use a constant-temperaturo bath.

The temperature of calibration must be

maintained within -tl* 0. and In the range

of 20' to 30' 0. The temperature of calibration and the temperature of analysis must be

within 2 degrees. Plot the ab=rbance n ainst

the total concentration in pg. SO0 for the

corresponding solution. The total rg. So, In

solution equals the concentration of the

standard (Section 0.2.0) in rg. SOs/mi. time

the ml. sulfite solution added (g. S0=--

,ig./ml. SO2XmL added). A linear relationship should be obtained, and the y-intercept

should be within 0.03 abzorbanco unit of the zero standard abzorbance. For maximum precislon determine the line of best fit using

regression analysis by the method of let

squares. Determine the slope of the line of

best fit, calculate its reciprocal and denote

as Bs. B. Is the calibration factor. (See Section 6.2.10.1 for specifications on the slope of

the calibration curve). This callbration fac- tor can be used for calculating results provided there are no radical changEs in

temperature or pH. At least one control

sample containing a known concentration of

SO for each series of determinations, la

recommended to Insure the reliability of this

factor.

8.2.2 Procedure withz SO Permcation

Tubes.

8.2.2.1 General Considerations. Atmospheres containing accurately known amounts of sulfur dioxide at levels of Interest can be

prepared using permeation tubes. In the

systems for generating theze atmosphere , the permeation tube emitS SO, gas at a known, low, constant rate, provided the tem- perature of the tube Is held constant (.!0.1-

C.)" and provided the tube has been accu- rately calibrated at the temperature of use. The SO, gas permeating from the tube is

carried by a low flow of Inert gas to a mlxIng chamber where It Is accurately diluted

with S02 -frce air to the level of litercLt and

the sample taken. Theze systems are s-hown

schematically in F gures A2 and A3 and have

been described in detail by O'Keeffo and

Ortman (9), Scarngelll, Frey, and Slt-man

(10), and Scaringelli, O'Kceffe, nosenberg,

and Bell (11).

8.2.2.2 Preparation of Standard Atmospheres. Permeation tubes may be prepared

s1s9

or purchae:L Scarlngelll. OHEeeffe, Rosenberg, and Bell (11) give detailed, explicit

directions for parmcatlon tube calibration.

Tubcs with a certified permeratlon rate are ava-labe from the Waflonsl Bureau of Standard, Tube permeation rates from 0.2 to 0.4

;g./mlnute Inert gas flows of about 50 mlj

minute and dilution air flow ra+te from 1.1 to 15 iters/minutes convenlently give standnrd at==phere- containing desired levels

of SO, (23 to 030 p-.!nm:; 0.01 to 0.15 p.p.

SO:). The concentration of SO. In any standard atmozzphero can ha calculated as follows:

PM103

C=-P,+R,

Where:

0 =Concentration of S0, r-./m. at ref- erenca conditions.

P =Tubo p emeation rate, p./mlnute.

RE=F1ow rate of dilution air, liter/minute at ref'erence conditions.

Pns=Flw rate of Inert gas, liter/m nute at rcference conditions.

810"' Sampling and Preparation of Calibratftm Curre'. Prepare a ceries (usually six) of standard atmospheres containing E02

levels.from 25 to p0 g. SO3 Im. 2

. Sample esch

atmosphere uzing similar apparatis and ta- ing exactly the same air volume as will be

done in atmcphIerc L-ampling. Determine

abszrbanccs az directed In 7.2. Plot the con- centration of 2% In rg./m 3 (x-axls) ag.ainst A-A values (-axis) draw, the straight line

of bcst fit and determine the slope. Alternatively, rere on nalyzi by the method

of least squares may be used to calculate the

slope. Calculate the reciprocal of the slope

and denote as B.

8.3 Sampling Efilclfej. Collection eiclency i, above G3 percent; effiMcency may

fall off, hoever, at concentrations below 25

ipgjfmA (12, 13) 9. Calculations.

9.1 Conrercion of Volume. Convert the

volume of air eampled to the volume at ref- erence conditions of 23" C. and 760 -m. Hg.

(On 2-hour samples, this may not be possible.)

P233

IGO t+273

V'=Volumo of air at 250 C. and 760 mm- Hg. liters.

V =Volume of air campled. liters.

P =Barometrio pressure, mm. Hg. t =Tempratur of air sample, 'C.

92 Sulfur Doide Concentration.

02.1 When sulfito solutloz are used to prep=ar calibration curves, compute the con- centratlon of sulfur dloxido In the sample: /

(A-Ao) (101) (B.)

g. SOdm.2 = D

Va

A =Sample abzorbance.

A,=lZeagent blank absorbance.

103=Convcsrlon of liters to cubic meters. Vn =The sample corrected to 25" C. and

70 rm.Hg. liters.

B, =Calbration factor, p./abzorbance

unit.

D =Dilutlon factor.

For 30-minute and 1-hour samples,

D=1.

For 21-hour cample,. D=10.

92.2 When SOz gas standard atmosphere3 ore uscd to prepare calibration curves, compute the culfur dioxide In the rample by the

following formula:

SO.,, pU./m,'= (A-Ao) 1. Bz

A =Sample abcorbance.

Aq=Rcaent blank abZorbance.

Ba=(SEc 8.2.2.3).

92.3 Coenrsion of rg./m.F to P.p.m.=If

desired, the concentration of sulfur dioxide

FEDERAL REGISTER, VOL 36, NO. 84-FRIDAY, APRIL 30, 1971
RULES AND REGULATIONS

may be calculated as p.p.m. SO, at reference

conditions as follows:

p.p.m. SO=--g. SO/m. X 3.82 X 10-4

10. Relerences.

(1) West, P. W., and Gaeke, G. C., "Fixation of Sulfur Dioxide as Sulfttomercurate III and Subsequent Colorlmetric Determination", Anal. Chem.

28, 1816 (1956).

(2) Ephraims, F., 'Inorganic Chemistry,"

p. 562, Edited by P.C.L. Thorne and

E. R. Roberts, 5th Edition, Interscience. (1948).

(3) Lyles, G. R., Dowling, F. B., and Blanchard, V. J., "Quantitative Determination of Formaldehyde in Parts Per

Hundred Million Concentration Level", J. Air Poll. Cont. Assoc. 15, 106

(1965).

(4) Scaringelli, F. P., Saltzman, B. E., and

Frey, S. A., "Spectrophotometric Determination of Atmospheric Sulfur

Dioxide", Anal. Chem. 39, 1709 (1967).

(5) Pate, J. B., Ammons, B. E., Swanson,

G. A., Lodge, J. P., Jr., "Nitrite Interference in Spectrophotometric Determination of Atmospheric Sulfur

Dioxide", Anal. Chem. 37, 942 (1965).

(6) Zurlo, N. and Griffini, A. M., "leasurement of the SO, Content of Air in the

Presence of Oxides of Nitrogen and

Heavy Metals", Med. Lavoro, 53, 330

(1962).

TRAP

(7) Scaringelli, F. P., Efers, L., Norris, D.,

and Hochhelser, S., "Enhanced Stability of Sulfur Dioxide in Solution",

Anal. Chem. 42, 1818 (1970).

(8) Lodge, J. P. Jr., Pate, J. B., Ammons,

B. E. and Swanson, G. A., "Uso of

Hypodermic Needles as Critical Orifices in Air Sampling," J. Air Poll.

Cont. Assoc. 16, 197 (1966).

(9) O'Keeffe, A. E., and Ortman, 0. C.,

"Primary Standards for Trace Gas

Analysis", Anal. Chem. 38, 760 (1966).

(10) Scaringelli, F. P., Frey, S. A., and Saltzman, B. E., "Evaluation of Teflon

Permeation Tubes for Use with Sulfur

Dioxide", Amer. mnd. Hygiene Assoc.

J. 28,260 (1967).

(11) Scaringelli, F. P., O'Kceffe, A. E., Rosenberg, E., and Bell. J. P., "Preparation

of Known Concentrations of Gases

and Vapors with Permeation Devices

Calibrated Gravimetrically", Anal,

Chem. 42, 871 (1970).

(12) Urone, P., Evans, J. B., and Noyes, C. M.,

"Tracer Techniques in Sulfur Dioxide Colorlmetric and Condttctiometric Methods", Anal Chem. 37, 1101

.(1965).

(13) Bostrom, C. E., "The Absorption of Sulfur Dioxide at Low Concentrations

(p.p.m.) Studied by an Isotopic

Tracer Method", Intern. J. Air Water

Poll. 9, 33 (1965).

VIEMBRANE

FILTER

orifice flow control.

TO AIR

PUMP

FLOWMETER

Figure Al. Sampling train.

FEDERAL REGISTER, VOL. 36, NO. 84-FRIDAY, APRIL 30, 1971

8190
RULES AND REGULATIONS

IFLOWMCTME

P~lo mc

l lRCE'UT,!,",

Ela

,R~ 

iYIM

AIC

WATERBSAR

UI , parI L frIyztl [tl Itl

I'telo AS. gc astll I -~ r cr =z~jL.

Armm B-MH~Esnucn 11rHof i-n TB=

DfLVMTA=OX OP SuMMMED PAnrTcULArS

MT TM AMOSPR (HEGH VOLUIZE

1. Piinciple and Applicability. 1.1 Air Is drawn into a covered housing and through a filter by means of a high-flow- rate blower at a flow rate (1.13 to 1.70 rn./

man.; 40 to 60 ftAmin.) that allows sus- pended particles having diameters of less

than 100 Am. (Stokes equivalent diameter) to pass to the Mlter surface. (1) Particles

-within the Size range of 100 to 0.1gm. diame- ter are ordinarily collected on glass fiber fil- ters. The mass concentration of suspended

particulates in the ambient air (pg./m. 2 ) Is

computed by measuring the mass of collected

particulates and the volume of air sampled.

1.2 This method Is applicable to icasurcrment of the ms concentration of su:pended

particulates in ambient air. Tho sio of the

sample collected is uually adcquate for

other analyzes.

2. Rangc and Scnsi iity

2.1 When the sampler I operated at an average flow rate of 1.70 mnL2 min. (CO ft./

min.) for 24 hour, an adcquate sample will

be obtained even in an atmosphere having concentratons of suspended partlculatca a low as 1 pZ./nL. If particulate lovelo are 'unusually high, a catisfactory cample may be

obtained in 0 to 8 hours or les. For dctcrmination of avera e concentrations of sus- pended parteulatcas in ambient air, a standard eamapling period of 2- hours is

recommended.

8191

2.2 Welght are determined to the neare-t m11iram, alrftw rates are determined to the nearest 0.03 m3ZMlLn. (1.0 ft:.3IinL),

times are determined to the nearest 2

mninutes and mna-s conacentration are re- pzrtel to the nearest microgram per cub.c

meter.

3. Irtcrferencmr

3.1 Particulato matter that Is oily, such

2s photochemical smog or wood smoke may

block the filter and cause a rapid drop in a vilow ata nonunfon rate. Dense tog or

high humidity van cauzo the i1ter to become

too wet and severely reduce the arfldw

through the liter.

3.2 Glas-flber filters are comparativey

insensftivo to changes in relative humidity, but cillected part'culates can be hygr- scoplc. (2)

4. Precifon, Accuracy, and Stab rty.

4.1. Based upan colborative testing, the

zelative standard deviation (coefcient of

variation) for single analyst variation (repeatab=ity of tht methcd) i- 3.0 percent

The corep3rdring value for multllahoratry

variation (reproduc=ty of the method) Is

.3.7 percent. (3)

4.2 The accuracy with which -the sampler

measure the true average -concentration

depends upon the constancy of the airflow

rate through the sampler. The alrdow rate is

affected by the concentration and the nature

of the dust in the atmosphere. Under these

condi iomn the error in the measured average concentration may be in excess of -t50

percent of the true average concentration. depending an the amount of reduction of air2w rate and on the variatin of the roars

concentration of dust with time during the

2A-hour sampling perlod. (4)

S. Apparatu!.

13.1 Sampling.

5.11 Sampler. The sanpler canssts of

three units: (1) the faceplate and gasket_ (2) the Mlter adapter aszembly, and (3) the motor unit. Figure BI shows an explded

view of these parts, their relationship to each

other, and how they are assembled, The

rampler mus+ be calpable of paszing envirnmental air through a 406.5 czm. (63 in. 2 )

porIton of a clean 203 by 24 cm- (8- by

10-n.) class-fiber filter at a rate of at least

1.'70 m.L/M1n. (C9 ftA'mi). The motor must be capable of continuous operation far -

ho~ Periods with input voltages ranging

frorm 110 to 120 volts, O-Co cycles alternating current and muzt have third-wire safety

ground. The housing for the motor unit

may be of any convenlent construction so

long a. the unit remains airtight and leakfree. The life of the tamplcr motor can be

extendLd by lowering the voltage by about

10 percent with a small "bu-_l or boost"

trans:former bcatween the saple n oa outlet.

5.1.2 Sampler Shelter. It I- Important

that the Lampler bo proparly Installed in a suitable shelter. Tha shelter Is cubjected to extr-me of temImp-aturC, humldty, znd all

typc3 of air pDllutants. For these re-s=

the matcr"- of the sh.ltr muzt be cl:ron

carefully. Propcely painted exterior ply7.'c.d:j

or heavy zauga Cluminum srve wall. The

Lampler must bo mountca vcrticualy in the

shcltcr CO that the Ca-fiber fiter Is pzrl1el w1th the ground. The shelter must he

prov.ided rdth a roof co that, the iter i:; pro- tcctcd from precipltation and debrL. The

Internal crr an:;mnt and confl.uration of

a sultable rhelter with a gable roef are zhewn

in ITgura B2. The clcarnco area bet-een tha

main houzing and the roef at itz clsezst

point should be r0.5_i935 em (c2-SO

in.). The main hoeuIng should he rec-tngtrlar, with dimcnsions of about 23 by sC cem

(11, by 14 In.).

5.13 rot-eter. ?-,Iard in arbitrary

units, frequently 0 to 70. and capable of

being calibrated. Other daviczs of at le-t

comparablo accuracy may be used.

FEDERAL REGISTER, VOL 36, NO. 84--FRIDAY, APMIL 30, 1971
8192

5.1.4 Orifice Calibration Unit. Consisting

of a metal tube 7.6 cm. (3 In.) ID and 15.9

cm. (6% in.) long with a static pressure tap

5.1 cm. (2 In.) from one end. See Figure

B3. The tube end nearest the pressure tap Is

flanged to about 10.8 cm. (4V in.) OD with

a male thread of the same size as the inlet

end of the high-volume air sampler. A single

metal plate 9.2 cm. (3% in.) in diameter and

0.24 cm. (%2 in.) thick with a central orifice

2.9 cm. (1% in.) in diameter is held in place

at the air inlet end with a female threaded'

ring. The other end of the tube is flanged to

hold a loose female threaded coupling, which

screws onto the inlet of the sampler. An 18-

hole metal plate, an integral part of the unit,

Is positioned between the orifice and sampler

to simuiate the resistance of a clean glassfiber filter. An orifice calibration unit is

shown In Figure B3.

5.1.5 Differential Manometer. Capable of

measuring to at least 40 cm. (16 in.) of

water.

5.1.6 Positive Displacement Meter. Calibrated in cubic meters or cubic feet, to be

used as a primary standard.

5.1.7 Barometer. Capable of measuring atmospheric pressure to the nearest mm.

5.2 Analysis.

5.2.1 Filter Conditioning Environment.

Balance room or desiccator maintained at

15 ° to 35°C. and less than 50 percent relative

humidity.

5.22 Analytical Balance. Equipped with

a weighing chamber designed to handle unfolded 20.3 by 25.4 cm. (8- by 10-in.) filters

and having a sensitivity of 0.1 mg.

5.2.3 Light Source. Frequently a table of

the type used to view X-ray films.

5.2.4 Numbering Device. Capable of printing identification numbers on the filters.

6. Reagents.

6.1 Filter Media. Glass-fiber filters having

a collection efficiency of at least 99 percent

for particles of 0.3 1m. diameter, as measured

by the DOP test, are suitable for the quantitative measurement of concentrations of suspended particulates, (5) although some other

medium, such as paper, may be desirable for

some analyses. If a more detailed analysis Is

contemplated, care must be exercised to use

filters that contain low background concentrations of the pollutant being investigated.

Careful quality control is required to determine background values of these pollutants.

7. Procedure. 7.1 Sampling.

7.1.1 Filter Preparation. Expose each filter

to the light source and inspect for pinholes,

particles, or other imperfections. Filters with

visible imperfections should not be used. A

small brush Is useful for removing particles.

Equilibrate the filters in the filter conditionIng environment for 24 hours. Weigh the

filters to the nearest mllligram,, record tare

weight and filter Identification number. Do

not bend or fold the filter before collection

of the sample.

7.1.2 Sample Collection. Open the shelter,

loosen the wing nuts, and remove the faceplate from the filter holder. Install a num'

bered, preweighed, glass-fiber filter in position (rough side up), replace the faceplate

without disturbing the filter, and fasten

securely. Undertightening will allow air leakage, overtightening will damage the spongerubber faceplate gasket. A very light application of talcum powder may be used on the

sponge-rubber faceplate gasket to prevent

the filter from sticking. During inclement

weather the sampler may be removed to a

protected area for filter change. Close the

roof of the shelter, run the sampler for about

5 minutes, connect the rotameter to the

nipple on the back of the sampler, and read

the rotameter ball with rotameter in a vertical position. Estimate to the nearest whole

number. If the ball is fluctuating rapidly,

tip the rotameter and slowly straighten it

RULES AND REGULATIONS

until the ball gives a constant reading. DIsconnect the rotameter from the nipple; record the initial rotameter reading and the

starting time and date on the filter folder.

(The rotameter should never be connected

to the sampler except when the flow is being

measured.) Sample for 24 hours from midnight to midnight and take a final rotameter

reading. Record the final rdtameter reading

and ending time and date on the filter folder.

Remove the faceplate as described above and

carefully remove the filter from the holder,

touching only the outer edges. Fold the filter

lengthwise so that only surfaces with collected particulates are In contact, and place

in a manila folder. Record on the folder the

filter number, location, and any other factors,

such as meteorological conditions or razing

of nearby buildings, that might affect the

results. If the sample is defective, void it at

this time. In order to obtain a valid sample,

the high-volume sampler must be operated

with the same rotameter and tubing that

were used during its calibration.

7.2 Analysis. Equilibrate the exposed filters for 24 hours in the filter conditioning

environment, then reweigh. After they are

weighed, the filters may be saved for detailed

chemical 6nalysis.

7.3 Maintenance.

7.3.1 Sampler Motor. Replace brushes

before they are worn to the point where

motor damage can occur.

7.3.2 Faceplate Gasket. Replace when the

margins of samples are no longer sharp. The

gasket may be sealed to the faceplate with

rublier cementor double-sided adhesive tape.

7.3.3 Rotameter. Clean as required, using

alcohol. .

8. Calibration.

8.1 Purpose. Since only a small portion

of the total air sampled passes through the

rotameter during measurement, the rotameter must be calibrated against actual airflow with the orifice calibration unit. Before

the orifice calibration unit caix be used to

calibrate the rotameter, the orifice calibration unit 4tself must be calibrated against

the positive displacement primary standard.

8.1.1 Orifice Calibration Unit. Attach the

orifice calibration unit to the intake end

of the positive displacement primary stand,-

ard and attach a high-volume motor blower

unit to the exhaust end of the primary

.standard. Connect one end of a differential

manometer to the differential pressure tap

of the orifice calibration unit and leave the

other end open to the atmosphere. Operate

the high-volume motor blower unit so that

a series of different, but constant, airflows

(usually six) are obtained for definite time

periods. Record the reading on the differential manometer at each airflow. The different

constant airflows are obtained by placing a,

series of loadplates, one at a time, between

the calibration unit and the primary standard. Placing the orifice before the inlet reduces the pressure at the inlet of the primary

standard below atmospheric; therefore, a

correction must be.made for the increase in

volume caused by this decreased inlet pressure. Attach one end of a second differential

manameter to an inlet pressure tap of the

primary standard and leave the other open

to the atmosphere. During each of the constant airflow measurements made above,

measure the true inlet pressure of the

primary standard with this second differential manometer. Measurp atmospheric pressure and temperature. Correct the measured

air volume to true air volume as directed in

9.1.1, then obtain true airflow rate, Q, as

directed in 9.1.3. Plot the differential manometer readings of the orifice unit versus Q.

8.1.2 High-Volume Sampler. Assemble a high-volume sampler with a clean filter in

place and run for at least 5 minutes. Attach

a rotameter, read the ball, adjust so that the

ball reads 65, and seal the adjusting mechanlsm so that it cannot be changed easily.

Shut off motor, remove the filter, and attach

the orifice calibration unit in Its place, Op.

erate the high-volume sampler at a cerlc3 of

different, but constant, airflovs (usually olx).

Record the reading of the dlfferential manometer on the orifice calibration unit, and

record the readings of the rotamoter at each

flow. Measure atmospherlo presuro and tomperature. Convert the differential manometer

reading to m./mln., 0. then plot rotamotpr

reading versus Q.

8.1.3 Correction for Differences in Presoure

or, Temperature. See Addendum B.

9. Calculations.

9.1 Calibration of Orifice.

9,1.1 True Air Volume. Caloulate the air

volume measured by the positive dlsplacement primary standard.

(PA-P M )

VX=-(V,)

PA

V,=True air volume at ltmozpherlo pres- "sure, i 3

P,=Baromotric pressure, mm. Hg,

Pm=Pressuro drop at inlot of primary

standard, mm. Hg.

Vu=Volume measured by primary t.Andord, m.3

9.1.2 Conversion Factors.

Inches Hg.X25.4mm. Hg.

Inches water X 73.48 >, 10-3=Inehes Hg.

Cubic feet aIrx<0.028t=oublo moters air,

9.1.3 True Airfloto Rate,

Vs

T

Q =Flow rate, m.5/mlmn

T=Tlme of flow, m11

9.2 Sample Volume,

9.2.1 Volume Conversion. Convert the Initial and final rotameter readinga to true

airflow rate, Q, using calibration curve of

8.12.

9.2.2 Calculate volume of air sampled

QlQ

V=-XT

2

V=Air volume sampled, m.8

Q, =Initial airflow rato, m.9/mln.

Qt =inal alrflow rate, mW/min.

T=Sampling time, min.

9.3 Calculate mass concentration of suspended particulates

(Wf-W) X.IOi

S.P.=

V

S.p.=Mas concentration of ousponded

particulates, pg/m.

Wi =Initial weight of filter, g.

Wt =Final weight of filter, g.

V=AIr volume sampled, m.'

104=Conversion of g. to pg.

10. References.

(1) Robson, C. D., and Foster, , V,

"Evaluation of Air Parteolato Sampling Equipment", Am. lnd. llyor.

Assoc. J. 24, 404 (1902).

(2) Tlerney, 0. P., and Conner, W, D.,

"Hygroscopic Effects on Weight Determinations of Particulates Collected on

Glass-Fiber Filters", Am Ind. fluy.

Assoc. J. 28, 363 (1967).

(3) Unpublished data based on a collaborative test Involving 12 partlolpants,

conducted under the direction of tile

Methods Standardization Servicei klootion of the National Air Pollution Control Administration, October, 1970.

(4) Harrison, W. X., Nader, J. S,, and Fugman, F. S., "Constant lovi Regulators

for High-Volume Air Sampler", Am.

-nd. Hyg. Assoo. J. 21, 114-120 (1960).

FEDERAL REGISTER, VOL. 36, NO. 84-FRIDAY, APRIL 30, 1971
RULES AND REGULATIONS

(5) Pate, J. B., and Tabor, E. C.. "Analytical

Aspects of the Use of Glass-Fiber Filters for the Collection and Analysis of

Atmospheric Particulate Matter", Am.

lZd. Hyg. ASsoc. J. 23, 144-150 (1962).

.ADDENDA

.A. A ternative Equipment.

A modification of the high-volume sampler

incorporating a method for recording the

actual airflow over the entire sampling period has been described, and is acceptable

for measuring the concentration of suspended particulates (Henderson. J.S., Eighth

Conference on Methods in Air Pollution and

Industrial Hygiene Studies, 1967. Oakland,

Calif.). This modification consists of an ex- lhaust orifice meter assembly connected

through a transducer to a system for con- tinuously recording airflow on a circular

chart. The volume of air sampled Is calculated by the following equation:

V=QXT.

Q=Average sampling rate, m. 3

/mln.

T=Sampling time, minutes.

The average sampling rate, Q, is determined

from the recorder chart by estimation if the

flow rate does not vary more than 0.11 rn 3

/

2nin. (4 It./mn.) during -the sampling period. If the flow rate does vary more than

0.11 mLP (4 ft.Plmin.) during the sampling

period, read the flow rate from the chart

at 2-hour intervals and take the average.

B. Pressure and Temperature Corrections.

rILTER

FOSIT103

If the prcaure or temprature during high-volume sampler calibration 13 cub;tan- tially different from the prc ura or tcmcra - ture during orlilce callbration, a carrc-i-tln

of the flow rate, Q, may ba rcqulrc:L If the

prZ~urco differ by no more than 1G pcrccnt

and the temperature differ by no more thnn

100 percent (OC), the errar in the un- corrected flow rate =ill be no oro thzn 15

percent. If ncwary. obtain the caerrcted

flow rate as directed below. ThIs correction

applIes only to orifice moters havlng a con- stant orifico caciflent. The cecilent for

the calibrating orifice dc:rlbed In 5.1.4 ha

been chown experLmentally to ba constant over the normal opcratmng range of the hlghvolume ca=mpler (0.6 to 2 mNmln.; 20 to 73

ft.P/min.). Calculate corrected flow rate:

QO=Corrected flow rate m./min.

OQ=Flow rate during high-volume campler

calibration (Eecton 8.1.2), m.3 /mln.

T1 =Abcoluto temperature during orifica

unit calibration (SEctlon 8.1.1), "1Z or .

P±=Baromctrlc pre--ure during oriice unit

calbration (Section 8.1.1), mm. Hg.

T2=Abzoluto temperature during highvolume rampler calibration (Section

8.1"). 1E or "R.

P:=Barometrla pre--ure during high-vol- umo sampler calibration (SEction

8.12). mm. Hg.

FJ~so SI. E~;~:l ~:~z ci Iy~1

.rl i-'~'~r!z~ rc:-;~f zls.

FEDERAL REGISTER, VOL 36, NO. 84-FRIDAY, APRIL 30, 1971

8193

NO. 81---t, 1I-2
RULES AND REGULATIONS

Figure 12. Assembled sampler and shelter.

ORIFICE RESISTANCE PLATES

Figure B3, Orifice calibration unit.

APPENDIX C-REFRENCE METHOD FOR THE

CONTINUOUS MEASUREENT OF CARBON

MONOXIDE IN THE ATIOSPHERE (NowDISPERsIVE INFRARED SPEcTROMETRY)

1. Principle and Applicability.

1.1 This method: is based on the absorption of infrared radiation by carbon monoxide. Energy from a source emitting radiation in the Infrared region is split into

parallel beams and directed through ref-i

erence and sample cells. Both beams pass

into matched cells, each containing a selective detector and CO. The CO in the cells

absorb infrared radiation only at its characteristic frequencies and the detector is sensitive to these frequencies. With a nonabsorbing gas in the reference cell, and with no

CO in the sample cell, the signals from

both detectors are balanced electronically.

Any CO introduced into the sample cell will

absorb radiation, which reduces the temperature and pressure in the detector cell and

displaces a diaphram. This, displacement is

detected electronically and amplified to provide an output signal.

1.2 This method is applicable to the dotermination of carbon monoxide in ambient

air, and to the analysis of gazes under

preszure. 2. Range and Sensittity.

2.1 Instruments are available that moa- ure in the range of 0 to 53 mg./m.8 (0-50

p.p.m.), which Is the range mozt commonly used for urban atmospheric c.ampling. tfost

instruments measure in additional ranges,

2.2 Sensitivity Is 1 percent of full-scale

response per 0.6 mg. CO/m.3 (0.6 p.p.m.).

3. Interferences.

3.1 Interferences vary between Individual

instruments. The efrect of carbon dtoxide

interference at normal concentratlonu Is

minimal. The primary Interference IS water

vapor, and with no correction may give an interference equivalent to as high as 12 nag.

CO/n' 3 Water vapor interference can be

minimized by (a) passIng the air sample

through silica gel or similar drying agents,

(b) maintaining constant humidity in the

sample and calibration gases by refrigeration, (c) saturating the air r-umplo and callration gases to maintain constant humidity or (d) using narrowband optical fltera

in combination with come of these measures. 3.2 Hydrocarbons at ambient levels do

not ordinarily interfere.

4. Precision, Accuracy, and Stability.

4.1 Precision determined, with calibration

gases Is t0.5 percent full scale in the 0-8

mg./m.3 range.

4.2 Accuracy deponds on Instrument

linearity and the absolute concentratlons

of the calibration gases. An accuraey of ± 1

percent of full scale in the 0-53 mg./nt

range can be obtAned.

4.3 Varlationz in ambient room tcmpeorture can cause changen equivalent to a much as 0.5 mg. CO/m.0 per °0. This offee can be minimized by operating the analyzer

in a temperature-controled room. Prettro

changes between span chcoks will causO

changes in instrument response, Zero drift

is usually less than ±1 percent of full scale

per 24 hours, if cell temperature and prej- sure are maintained constant.

5. Apparatus.

5.1 Carbon Monoxide Analyzer. Connercially available instruments should be installed on location and demonstrated, pref- erably by the manufacturer, to meeot or exceed manufacturers specifications and

those described In this method.

5.2 Sample Introduction System. Pump,

flow control valve, and flowmeter.

5.3 Filtef (In-line). A filter wth a porosity of 2 to 10 microns should be Used to

keep large particles from the sample coll.

5.4 Moisture Control, Refrigeration units are available with some commercial Instruments for maintaining constant humidity. Drying tubes (vith sufficient capacity to operate for 72 hours) containing Indicating silica gel can be used. Other techniquea that

prevent the Interference of moisture are satisfactory.

6. Reagents.

6.1 Zero Gas. Nitrozen or helium cont-aining less than 0.1 mag. CO/m.3

6.2 Calibration Gages. Calibration twea

corresponding to 10, 20, 40, and 80 percent

of full scale axe used. Gase must be provided with certification or guarinecd analysls of carbon monoxid6 content,

6.3 Span Gas. The calibration ga corre- sponding to 80 percent of full scale Is used

to span the instrument.

7. Procedure.

7.1 Calibrate the instrument as descrlbed

in 8.1. All gases (sample, zero, calibration,

and span) must be introduced into the en- tire analyzer system. Plguro 01 showo a typical flow diagram. ror specific operating

Instructions, refer to the manufacturer'a

manual. -

FEDERAL REGISTER, VOL. 36, NO. 84-FRIDAY, APRIL 30, 1971
RULES AND REGULATIONS

8. Caiibratiofl.

8.1 Calibration Curve. Determine the

linearity of the detector response at the

operating flow rate and temperature. Prepare a calibration curve and check the curve

-furnished with the instrument. Introducezero gas and set the zero control to indicate

a recorder reading of zero. Introduce span

gas and adjust the span control to indicate

the proper value on the recorder scale (e.g.-

on 0-58 mg./m-3 scale, set the 46 mg./m.

standard at 80 percent of the recorder

cha3t). Recheck zero and span until adjustments are no longer necessary. Introduce

intermediate calibration gases and plot the

-values obtained. If a smooth curve is not

obtained, calibration gases may need

replacement.

- 9. Calculations.

9.1 Determine the concentrations directly

from the calibration curve. No calculations

are necessary.

9.2 Carbon monoxide concentrations in

mg./m.S are converted to p.pam. as follows:

p.p.m. CO=mg. CO/m. X0.873

10. Bibliography.

The Intech NDIR-CO Analyzer by Prank

McElroy. Presented at the llth Methods

Conference in Air Pollution, University of

California, Berkeley, Calif., April 1, 1970.

Jacobs, B. B. et al., J.A.P.C.A. 9, No. 2,

110114, August 1959.

M A LIRA Infrared Gas and Liquid Analyzer Instruction Book, Mine Safety Appliances Co., Pittsburgh, Pa.

Beckman Instruction 1635B, Models 215A,

315A and 415A Infrared Analyzers, Beckman

Instrument Company, Fullerton, Calif.

Continuous CO Monitoring System, Model

A-5611, Intertech Corp., Princeton, N.J.

Bendix-UNOR Infrared Gas Analyzer,.

Ronceverte, W. Va.

A'nDENDA

A. Suggested. Performance Specifications

for NDIR Carbon 3onoxide Analyzers:

Range (minimut) ---- 0-58 mg./m.'

(0-50 p.pm).

Output (minimum) --- 0-10, 100, 1,000,-

5,000 my. full

scale.

Minimum detectable sen- 0.6 mg./ m 3 (0.5

sitivity. - p-pm.).

Lag time (miximum)-- 15 seconds.

Time to 90 percent re- 30 seconds.

sponse (maximum).

Rise time, 90 percent 15 seconds.

(maximum).

Fall time, 90 percent 15 seconds. (nimumL.

Zero drift (maximum)--- 3 percent/week.

not to exceed

1 percent/24

hours.

Span drift (maximum)-- .3 percent/week,

not to exceed

1 percent/24

hours.

Precision (minimum)--- __0.5 percent.

Operational period -(min- 3 days.

imum).

Noise (maximum) ------- -±0.5 percent.

Interference equivalent. 1 percent of full

(maximum). scale. -

Operating temperature 5-40' C.

range (minimum).

Operating humidity range 10-100 percent.

(minimum).

Linearity (maximum de- 1 percent of full

viation). scale.

B. Suggested Definitions of Performance

Specifications:

Range-The minimum and maximum measurement limits.

Output-Electrical signal which Is proportional to the measurement: intended for

connection to readout or datA processing

devices. Usually expressed as millivolts or

milliamps full scale at a given impedance.

Pull Scale-The maximum measuring limit

for a given range.

Minimum Detectable Sensitivity-The smallest amount of input concentration that

can be detected as the concentration approaches zero.

Accur acy-The degree of agreement between a measured value and the true value; usually expressed as _ percent of full ccale

Lag Time--The time interval from a step

change In Input concentration at the Instrument inlet to the first corresponding

change in the instrument output.

Time to 90 percent Re:ponse-The time Interval from a step change in the input

concentration at the instrument Inlet to

a reading of 90 percent of the ultimate

recorded concentration.

Rise Time (90 percent)-The nterval between initial response time and time to 90

percent response after a step ncreo in

the Inlet concentration.

Fall Time (90 percent)-Tho interval between initial response time and time to

90 percent response after a step decrease

in the inlet concentmton.

Zero Drift-The change In instrument output over a stated time period, usually 24

hours, of unadjusted continuous operation, when the Input concentration is

zero; usually eapreased as percent full

scale.

SA%'PLE IHTRODUCT10WI

APPm.rmxx D-REF EE N MMHOin ron T1n

MU&sunxRnEr OF PHOrOCE=mL OxM.%rrrm

CoasR~crm ) oa INr=.ainrcrs DvE zo Nrr rouo OxmD Aimo SuLrru Dioxmn

1. Principle and Applicability.

1.1 Ambient air and ethylene ae delivered simultaneously to a mixing zonO

where the ozone in the air reacts with the

ethylene to emit light which ts detected by

a photomultipiler tube. The resulting photocurrent is amplifled and Is either read directly or displayed on a recorder.

1.2 The method is applicable to the continuous measurement of ozone in ambient

air.

2. Range and Sensitfirty,

2.1 The range is 9.8 pg. O.m.5 to greater

than 1960 Ng. Oinm.8 (0.005 p.pxm 0 to

grpater than 1 p.pm. 0,).

Span, DrIft-The ch ge In instrumint output over a sted time period, usually 24

hours, of unadju:-ted continuous operation, when the Input concentration is a

stated upscale value; usually expresed as

percent full scale.

Precison-The degree of agreement between

repeated me-surements of the ""ie concentration. expresed as the average deviation of the ringle results from the mean.

Operational Period-Tho pcriod of time o-er

which the instrument can be expected to

operate unattended within specifications.

NoeL-Spontaneouo deviations from a mean

output not caused by input concentration

changes.

Xnterference-An undesired pocitive or negative output cauced by a Substance other

than the one being me-mured.

Interference Equivalent-The portion of

indicated Input concent-atfon due to the

presence of an Interferent.

Operating Temperature Range-The range

of ambient temperatures o-er which the

instrument will meet all performance

pecwficatlons.

Operating Humidity lange--The range of

ambient relative humidity over which the

Instrument will meet all performance

specfilcations.

Linearity-The m-aimum devlation between

an actual ismtrument reading and the

reading predicted by a straight line drawn

between upper and lower calibration

points.

2.2 The s'-,itivity 13 9.8 pg. O,0 s (0.005 p.pM. 03).

3. lntcrfcrcC3ce.

3.1 Other oxid ng and reducing species

normally found in ambient air do not interfere.

4. Prccsi~on and Accuracy.

4.1 The average deviation from the mean

of repeated single measurements does not exceed 5 percent of the mean of the m-easure- ments.

4.2 The mothod is accurate within -7

percent.

5. Appzratu3.

5.1 D tector Ccll. Figure DI is a draz inof a typical detector cell showing dow pa. th

of gaes., the miin zone, and pLacement of

the photomultiplier tube. Other flow p3fhz

in which the air and ethylene streamn meet

FEDERAL REGISTER, VOL 36, NO. 84-FRIDAY, APRIL 30, 1971

8195-

Ff:=Cf.
8196

at a point near the photomultiplier tube are

also allowable.

5.2 Air Flowmeter. A device capable of

controlling air flows between 0-1.5 I/mi.

5.3 Ethylene Flowmeter. A device capable

of controlling ethylene flows between 0-50

ml./min. At any flow in this range, the device'

should be capable of maintaining constant

flow rate within ±3 ml./min.

5.4 Air Inlet Filter. A Teflon filter

capable of removing all particles greater than

5 microns In diameter.

5.5 Photomultiplier Tube. A high gain

low dark current (not more than. lxl0-D

ampere) photomultlpller tube having its

maximum gain at about 430 nm. The following tubes are satisfactory: RCA 4507,

RCA 8575, EAI 9750, EAU 9524, and EMI

9536.

5.6 High Voltage Power Supply. Capable

of delivering up to 2,000 volts.

5.7 Direct Current Amplifier. Capable of

full scale amplification of currents from 10-"0 to 10-7 ampere; an electrometer Is commonly

used.

5.8 Recorder. Capable of full scale display

of voltages from the DC amplifier. These voltages commonly are In the 1 millivolt to 1-volt

range.

5.9 Ozone Source and Dilution System.

The ozone source consists of a quartz tube

into which ozone-free air s introduced and

then irradiated with a very stable low pres- sure mercury lamp. The level of irradiation is

controlled by an adjustable aluminum sleeve

'which fits around the lamp. Ozone concen- trations are varied by adjustment of this

sleeve. At a fixed level of irradiation, ozone is

produced at a constant rate. By carefully

controlling the flow of air through the quartz

tube, atmospheres are generated which con- tain constant concentrations of ozone. The

levels of ozone in the test atmospheres are determined by the neutral buffered potas- sium Iodide method (see section 8). This ozone source and dilution system is shown

schematically In Figures D2 and D3, and has

been described by Hodgeson, Stevens, and

Martin.

5.10 Apparatus for Calibration

5.10.1 Absorber. All-glass impingers as shown In Figure D4 are recommended. The

Impingers may be purchased from most ma- Jor glassware suppliers. Two absorbers in

series are needed to insure complete collection of the sample.

5.10.2 Air Pump. Capable of drawing 1

liter/minute through the absorbers. The

pump should be equipped with a needle valve on the inlet side to regulate aow. 5.10.3 Thermometer. With an accuracy

of ±20 C.

5.10.4 Barometer. Accurate to the nearest mm. Hg.

5.10.5 Flowmeter. Calibrated metering device for measuring flow up to 1 liter/minute

within ±2 percent. (For measuring flow

through Impingers.) 5.10.6 Flowmeter. For measuring airflow

past the lamp; must be capable of measuring

flows from 2 to 15 liters/minute within ±5

percent.

5.10.7 Trap. Containing glass wool to protect needle valve.

5.10.8 Volumetric Flasks. 25, 100, 500,

1,000 ml.

5.10.9 Buret. 50 ml.

5.10.10 Pipets. 0.5, 1, 2, 3, 4, 10, 25, and

50 ml. volumetric.

5.10.11 Erlenmeyer Flasks. 300 ml.

5.10.12 Spectrophotometer. Capable of

measuring absorbance at 352 nm. Matched

1-cm. cells should be used.

6. Reagents.

6.1 Ethylene. C. P. grade (minimum).

6.2 Cylinder Air. Dry grade.

6.3 Activated Charcoal Trap. For filtering

cylinder air.

RULES AND REGULATIONS

6.4 Purified Water. Used for all reagents.

To distilled or delonized water in an all-glass

distillation apparatus, add a crystal of potassium permanganate and a crystal of barium

hydroxide, and redistill.

6.5 Absorbing Reagent. Dissolve 13.6 g.

potassium dihydrogen phosphate (KBIPO4),

14.2 g. anhydrous disodium hydrogen phosphate (Na2 HPO4 ) or 35.8 g. dodecahydrate

salt (NaHPO412HEO), and 10.0 g. potassium

iodide (KI) in purified water and dilute to 1,000 ml. The pH should be 6.8+0.2. The

.solution Is stable f9r several weeks, if stored

in a glass-stoppered amber bottle in a cool,

dark place. -

6.6 Standard Arsenious Oxide Solution

(0.05 N). Use primary standard grade arse- nious oxide (AspO). Dry 1 hour at 105" C.

immediately before using. Accurately Weigh

2.4 g. arsenious oxide from a small glassstoppered weighing bottle. Dissolve in 25 ml.

1 N sodium hydroxide in a flask or beaker on a steam bath. Add 25 ml. 1 N sulfuric acid.

Cool, transfer quantitatively to a 1,000-ml.

volumetric flask, and dilute to volume. NoTE:

Solution must be neutral to litmus, not alkaline.

wt As.O, (g.)

Normality AsOa=-

49.46

6.7 Starch Indicator Solution (0.2 percent). Triturate 0.4 g. soluble starch and approximately 2 mg. mercuric Iodide (preservative) with a little water. Add the paste slowly to 200 ml. of boiling water. Continue boiling

until the solution is clear, allow to cool, and

transfer to a glass-stoppered bottle.

6.8 Standard Iodine Solution (0.05 N).

6.8.1 Preparation. Dissolve 5.0 g. potassium iodide (KI) and 3.2 g. resublimed iodine

(12) in 10 ml. purified water. When the f~dine

dissolves, transfer the solution to a 500-mi.

glass-stoppered volumetric flask. Dilute to mark with purified water and mix thoroughly. Keep solution in a dark brown glassstoppered bottle away from light, and re- standardize as necessary.

6.8.2 Standardization. Pipet accurately 20

ml. standard arsenious oxide solution into a 300-ml. Erlenmeyer flask. Acidify slightly

with 1:10 sulfuric acid, neutralize with solid

sodium bicarbonate, and add about 2 g. ex- cess. Titrate with the standard iodine solution using 5 ml. starch solution as indicator.

Saturate the solution with carbon dioxide near the end point by adding 1 ml. of 1:10

sulfuric acid. Continue the titration to the

first -appearance of a blue color which persists for 30 seconds.

ml. As2OXNormallty AsO 3 Normality I-=

ml. 12

6.9 Diluted Standard Iodine. Immediately

before use, pipet 1 ml. standard iodine solution into a 100-ml. volumetric flask and

dilute to volume with absorbing reagent.

7. Procedure.

7.1 Instruments can be constructed from

the components given here or may be pur-

'chased. If commercial instruments are used,

follow the specific instructions given in the

manufacturer's manual. Calibrate the nstrument as directed in section 8. Introduce

samples into the system under the same conditions of pressure and flow rate as are used

in calibration. By proper adjustments of zero

and span controls, direct reading of ozone

concentration is possible.

8. Calibration.

8.1 HI Calibration Curve. Prepare a curve

of absorbance of various Iodine solutions

against calculated ozone equivalents as

follows:

8.1.1 Into a series of 25 ml. volumetrio

flasks, pipet 0.5, 1, 2, 3, and 4 ml. of diluted

standard Iodine solution (6.0). Diluto each to the mark with absorbing reagent. Mix

thoroughly, and Immediately read the absorbance of each at 352 nrn. against imesipored absorbing reagent as the reference.

8.1.2 Calculate the concentration of the

solutions as total pg. Oa as follows:

Total jzg. 0,= (N) (00) (VI)

N=Normallty I4 (sea 68.2), meq./ml.

V,=Volumo of diluted Mandard Ij added,

ml. (0.5, 1, 2, 3, 4).

Plot absorbanco versus total pg., . 8.2 Instrument Calibration,

8.2.1 Generation of Test Atmos'phres. Assemblo the apparatus as shown In Figuro D3.

The ozone concentration produced by the

generator can be varied by changing the po- sition of the adjustable sleeve. For calibration of ambient air analyzers, the ozone source should be capable of produoing ozono concentrations In the range 100 to 1,000

1g./m.' (0.05 to 0.6 p.p.m.) at a flow rate of at least 5 liters per minute. At all times the

airflow through the generator mu5t be great- er ,than the total flow required by the sam- pling systems.

8.2.2 Sampling and Analyses of Test Atmospheres. Asssmblo the KI sampling train as shown In Flguro D4. Use ground-glas

connections upstream from the Impingtr. Butt-to-butt connections with Tygon tubing

may be used. The manifold distributing thlo test atmospheres must be sampled simultaneously by the KI sampling train and the

instrument to be calibrated. Cheek assrem- bled systems for leaks. Record the instru- ment response In nanoamperes at each

concentration (usually six). E tablish thoe

concentrations by analysis, using the neu- tral buffered potassium Iodide method as follows:

82.2.1 Blan:. With ozone lamp off, flu h

the system for several minutes to remove residual ozone. Pipot 10 ml. absorbing re- agent into each absorber. Draw air from the

ozone-generating system through the sam- pling train at 0.2 to 1 liter/minute for 10

minutes. Immediately transfer the exposed solution to a clean 1-cm, cell. Determine the

absorbance at 352 nm. against unexposed absorbing reagent as the reference. If the

system blank gives an absorbance, continue

flushing the ozone generation system until no absorbance is obtained.

8.2.2.2 Test Atmospheres. With the ozone

lamp operating, equilibrato the system for

about 10 minutes. Pipet 10 ml. of abs-orblng

reagent into each absorber and collect camples for 10 minutes In the concentration

range desired for calibration. Immediately

transfer the solutions from the two absorbers to clean 1-cm. cells. Determine the absorbance of each at 352 nm. against unexposed absorbing reagent as the reference. Add

the absorbances of the two solutions to obtain total abzorbanceo. Read total ,g.O.1 from

the calibration curve (see 8.1). Calculate to- tal volume of air sampled correeted to ref- erence conditions of 25* C. and 760 mm. 11g. as follows:

1 298 Vn"VX- *' - X'10-a

760 t+273

Va =Volume of air at reference condltions, m.3

V =Volume of air at sampling condltons, liters.

P =Barometrlc pressure at sampling

conditions, mm. Hg.

t =Temperature at sampllng conditions,

Co.

10-3= Conversilon of liters to in.3

FEDERAL REGISTER, VOL 36, NO. 84-FRIDAY, APRIL 30, 1971
RULES AND REGULATIONS

Calculate ozone concentration in popxm. as 9.3 Converlon botween p p. and p,

follows: m.t valuc3 for czono can be made o.a follwa:

1g. o0

p.p.m. 03=- X5.10 X 10-

VU

82.3 Instrument Calibration Curve. Instrument response from the photomultlplier

tube Is ordinarily in current or voltage. Plot

the current, or voltage if appropriate,

(y-axis) for the test atmospheres against ozone concentration as determined by the

neutral buffered potassium Iodide methcd,

in p.pJm. (x-axis).

9. Calculations.

9.1 If a recorder is used which has been

properly zeroed and spanned, ozone concen- trations can be read directly.

9.2 If the DC amplifier is read directly, the reading must be converted to ozone concentrations using the instrument calibration curve (8.2.3).

SAMPLE AIR IN

EXHAUST

p.p~M. 0j= - V.;5.10"*' 10-,

10. Bibliograp7y.

Hodgczon, J. A., Martin. B. El.. and Baumgardner. 3R E., "Comparicon of Chemliumlnezcent Methods for Mea.urement of Atmozpherlo Ozone". PboZr= In Analyttcal

Chemltry. Vol. V. Plenum Prcza, 1971.

Hodgc:on, J. A., Stevenw, R. K, and Martin,

B. E., "A Stablo Ozone Source Applicable as a Secondary Standard for Calibration of Atmospl eric Monitora", AnnlyaL Intrumtentation Sympocfum. Instrument Society of

America, Houoton, T .. , April 1971.

Nederbragt, G. W, Van der Horat, A., and

Van Duljn. J., Mature 20G, 87 (190).

Warren, G. J., and Babcock, G., Rev. Scf.

Intr. 4Z, 28D (1070).

, ETHYLENE IN

rm

PYRF. CONSTRU"TION

I- 4A 0.0.

FLAT

Figure D1. Detector cell.

FEDERAL REGISTER, VOL 36, NO. 84-FRIDAY, APRIL 30, 1971

8197

m a I-
RULES AND REGULATIONS

APPENDIX E-REFERENCE MrmOD POr DETim-

=Iu;ATION Or HYDROCARBOiS CORECTED 3OR

METHAN4E

1. Principle and Applicability.

1.1 Measured volumes of air are delivered

semicontinuously (4 to 12 times per hour)

to a hydrogen flame Ionization detector to measure its total hydrocarbon (THC) con- tent. An aliquot of the same air sample is

Introduced into a stripper column which re- moves water, carbon dioxide, hydrocarbons

other than methane, and carbon monoxide.

Methane and carbon monoxide are passed

quantitatively to a gas chromatographic col- umn where they are separated. The methane

Is eluted first, and is passed unchanged

through a catalytic reduction tube into the

flame Ionization detector. The carbon monox- Ide Is eluted Into the catalytic reduction

tube where It is reduced to methane before

passing through the flame ionization de- tector. Between analyses the stripper column

is backfluihed to .prepare it for subsequent

analysis. Hydrocarbon concentrations cor- rected for methane are determined by subtracting the methane value from the total

hydrocarbon value.

Two modes of operation are possible: (1) A complete chromatographic analysis showing the continuous output from the detector

for each sample injection; (2) The system

is programed for automatic zero and span to display selected band wldths of the

chromatogram. The peak height Is then usea as the measure of the concentration. The

former operation is referred to as the chromatographic or spectro mode and the latter as the barographic or "normal" mode depending on the make of analyzer.

1.2 The method is applicable to the semlcontinuous measurement of hydrocarbons

corrected for methane in ambient air. The

carbon monoxide measurement, which is

simultaneously obtained In this method, is not required In making measurements of

hydrocarbons corrected for methane and will

not be dealt with here.

2. Range and Sensitivity.

2.1 Instruments are available with vari- ous range combinations. For atmospheric

analysis the THO range is 0-13.1 mg./m s

(0-20 p.pan.) carbon (asC.H,) and the meth- ane range Is 0-6.55 mg/m.3 (0-10 p.p~m.). For

special applications, lower ranges are available and in these applications the range for

THO is 0-1.31 mg./m.3 (0-2 p.pm.) carbon

(as CH,) and for methane the range is 0-1.31

mg./m.3 (0-2 p.pmn.).

2.2 For the higher, atmospheric analysis

ranges the sensitivity for THO is 0.065

mg./m 3 (0.1 p.pmn.) carbon (as 4

,H) and

for methane the sensitivity is 0.033 mg./m.3

(0.05 p.p.m.). For the lower, special analysis

ranges the sensitivity is 0.016-mg./m.5 (0.025

p.pa.) for each gas.

3. Interferences.

3.1 No interference in the methane meas- urement has been observed. The THe meas- urement typically includes all or a portion

of what is generally classified as the air

peak interference. This effect is minimized

by proper plumbing arrangements or is ne- gated electronically.

4. Precision, Accuracy, and Stability.

4.1 Precision determined with calibration gases is +0.5 percent of full scale in

the higher, atmospheric analysis ranges. 4.2 Accuracy is dependent on instrument

linearity and absolute concentration of the

calibration gases. An accuracy of 1 percent of

full scale in the higher, atmospheric analysis ranges and 2 percent of full scale in

the lower, special analysis ranges can be

obtained.

4.3 Variations in ambient room tempera- ture can cause changes in performance chartacterstles. This is due to shifts in oven temperature, flow rates, and pressure with

ambient temperature change. The instru- ment should meet performance specifications

with room temperature changes of ±.3* C.

Baseline drift Is automatically corrected in

the barographic mode.

5. Apparatus.

5.1 Commercially Available THC, CH4, and CO Analyzer. Instruments should be Installed on location and demonstrated,

preferably by thd manufacturer, or his representative, to meet or exceed manufacturer's

specifications and those described in this

method.

5.2 Sample Introduction System. Pump,

flow control valves, automatic switching

valves, and flowmeter.

5.3 Filter (In-lfne). A binder-free, glasfiber filter with a porosity of 3 to 5 mIcronz

should be immediately downstream from the

sample pump.

5.4 Stripper or Precolumn. Located out- side of the oven at ambient temperature.

The column should be repacked or replaced

after the equivalent of 2 months of continu- ous operation.

5.5 Oven. For containing the analytical

column and catalytic converter. The oven

should be capable of maintaining an elevated

temperature constant within ±0.5* C. The

specific temperature varies with instrument

manufacturer.

6. Reagents.

6.1 Combustion Gas. Air containing less

than 1.3 mg./m.S (2 p.pm.) hydrocarboll as methane.

6.2 Fuel. Hydrogen or a mixture of hydrogen and inert gas containing less than 0.065

mg./m.3 (0.1 p.pm.) hydrocarbons as methane.

6.3 Carrier Gas. Helium, nitrogen, air or hydrogen containing less than 0..065 mg./m.8

(0.1 p.p~m.) hydrocarbons as methane.

6.4 Zero Gas. Air containing less than

0.065 mg./m.3 (0.1 p.p~m.) total hydrocarbons as methane.

6.5 Calibration Gases. Gases needed for

linearity checks (peak heights) are determined by the ranges used. Calibration gases corresponding to 10, 20, 40, and 80 percent

of full scale are needed. Gases must be provided with certification or guaranteed analysis. Methane Is used for both the total

hydrocarbon measurement and methane

measurement.

6.6 Span Gas. The calibration gas corre- sponding to 80 percent of full scale is used

to, span the instrument.

7. Procedure.

7.1 Calibrate the Instrument as described

in 8.1. Introduce sample into the system

under the same conditions of pressure and

flow rates as are used in calibration. (The

pump is bypassed only when pressurized cylinder gases are used.) Figure El shows a typical flow diagram; for specific operating instructions refer to manufacturer's manual

8. Calibration.

-8.1 Calibration Curve. Determine the

linearity of the system for THC and methane

in the barographic mode by introducing zero gas and adjusting the respective zeroing con- trols to indicate a recorder reading of zero. Introduce the span gas and adjust the span control to indicate the proper value on the

recorder scale. Recheck zero and span until

adjustments are no longer necessary. Introduce intermediate calibration gases and plot

the values obtained. If a smooth curve Is not obtained, calibration gases may need replace- ment.

9. Calculation.

9.1 Determine concentrations of total

hydrocarbons (as CH,) and CH,, directly from

the calibration curves. No calculations are necessary.

9.2 Determine concentration of hydrocarbons corrected for methane by subtraoting

the mbthane concentration from the total

hydrocarbon concentration.

9.3 Conversion botween p.p.m. and mg,/

in.S values for total hydrocarbons (ms CH,)

methane and hydrocarbons correoted for

methane are made as follows:

p.p.m. carbon (as CH4=[mg. carbon (as

CH)/m.8 X1.53

10. Bibliography.

Fee, G., "Multi-Parameter Air Quality

Analyzer", ISA Proceedings AID/OHLA'PID

Symposium, Houston, Texas, April 10-21,

1971.

Villalobos, R., and Chapman, n. L., "A Oas

Chromatographic Method for Automatic

Monitoring of Pollutants in Ambient Air",

Ibid.

Stevens, n. X., "The Automated Gas

Chromatograph as an Air Pollutant Monitor", 1970 Conference on Environmental

Toxicology, U.S. Air Force, Wrlght-Pattereon

Air Force Base, Dayton, Ohio.

Stevens, R. K., and O'Kceffo, A. V., Anal.

Chem. 42, 143A (1970).

Schuck, E. A., Altshuller, A. P., Barth, D, S.

and Morgan, G. B., "Relationship of Hydrocarbons to Oxidants In Ambient Atmospheres", J. Air Poll. Cont. Assoo. 20, 297-302

(1970).

Stevens, R. K,, O'Eeeffe, A. V., and Ortman,

G. C., "A Gas Chromatographic Approach to the Semi-Continuous Monitoring of Atmospherio Carbon Monoxido and Methane", Proceedings of 11th Conference on Methods in

Air Pollution on Industrial Hygiene Studies,

Berkeley, Calif., March 30-April 1, 1070,

Swinnerton, J. W., Linnenbom, V. J. and

Check, C. H., Environ. Sed. Tcchnol. 3, 830

(1069).

Williams, 1. G., Advances in ChromatoraphV, Giddings, J. C,, and Keller, n. A., edItors, Marcell Dekker, N.Y. (1960), pp. 178-

182.

Altshuller, A. P., Kopcznsld, S. L., Lonnamn, W. A., Becker, T. L. and Slater, n.,

Environ. Sd. Technol. 1, 899 (1907).

Altshuller, A. P., Cohen, t, n., and Purcell,

T. C., Can. J. Chem., 44, 2973 (1060).

DuBols, L., Zdrojowskl, A., and Monlann,

.T. L., J. Air Poll. Cont. Assoc, 10, 130 (1060).

Ortman, G. 0., Anal. Ohem. 38, 641-010

(1066).

Porter, K., and Volmann, D. H., Anal. Chem,

34,748-749 (1962).

Crum, W. M., Proceedings, National Analysis Instrumentation Symposium ISA, 1002.

Schwink, A., Hochenborg, H., and Forderreuther, M., Brennstoff-Chemo 72, No. 0, 205

(1061).

Instruction Manual for Air Quality Chromatograph Model 6800, Beckman Instrument

Co., Fulerton, Calif.

Instruction Manual, Bendix Corp., ionceverte, W. Va.

Instruction Manual, Byron Instrument Co,,

Raleigh, N.C.

MSA Instruction Manual for GO Process

Analyzer for Total Hydrocarbon, Methano

and Carbon Monoxide, Pittsburgh, Pa.

Monsanto Enviro-hom System for Total

Hydrocarbons, Methane and Carbon Monoxide Instruction Manual, Dayton, Ohio,

Union Carbide Inrtructlon Manual for

Model 3020 Gas Chromatograph for COCHC-T/1, White Plains, N.Y.

Instruction Manual for 350 V Analyzer,

Tracer Inc., Austin, Tex.

FEDEIAL REGISTER. VOL 36. NO. 84-FRIDAY, APRIL 30, 1971

8198

"! • f
RULES AND REGULATIONS

ALUMUU!,

C-In. PEN-RAY BOY Et:CLO:'URE

LAMP

-14 In. -LLAR

3- Jl n . .

- rn~ I ___ I I

QUARTZ TUBE, 15-m 0.0. in. ij

Figure D2. Ozenoc ourco.

1 FLO'[ METER

(0-10 Ilter..min)

NEEDLE

VALVE

I FLOW

CONTROLLM

Ffgure D3. Ozone calibration air oupply. souco, ani

manifold syst" .

FEDERAL REGISTER, VOL 36, NO. 84-FRIDAY, APPIL 30, 1971

S litcrckri!n

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$S199

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8200 RULES AND REGULATIONS

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samples collected from a standard test atmosphere. Precision would probably be different when the analysis is performed

manually.

4.2 No accuracy data are available.

4.3 Samples are stable for at least 6 weeks.

5. Apparatus.

5.1 Sampling. See Figure Fl.

5.1.1 Absorber. Polypropylene tubes 164 x

32 mm., equipped with polypropylene twoport closures.* Rubber stoppers cause high

and varying blank values and should not be

used. A gas dispersion tube with a fritted

end of porosity B (70-100 pm. maximum pore

diameter) is used.

5.1.1.1 Measurement of Maximum Pore

Diameter of Frit. Carefully clean the frit with

dichromate-concentrated sulfuric acid cleaning solution and rinse well with distilled

water. Insert through one hole of a two-hole

rubber stopper and install in a test tube containing sufficient distilled water to cover the

fritted portion. Attach a vacuum source to

the other hole of the rubber stopper and

measure the vacuum required to draw the

first perceptible stream of air bubbles through

the frit. Apply the following equation:

30s

maximum pore diameter, pm.= -

s=Surface tension of water in dynes/cm.

at the test temperature (73 at 18- C.,

72 at 25* C., and 71 at 310 C.).

P=Measured vacuum, am. Hg.

5.1.2 Probe. Teflon, polypropylene, or

glass tube with a polypropylene or glass funnel at the end and a membrane filter to protect the frit. Replace filter after collecting

five samples, or more often as indicated by

visual observation of the loading.

5.1.3 Flow Control Device. Calibrated 27-

gauge hypodermic needle, three-eighths of

an inch long to maintain a flow of approximately 0.2 liter/minute. The needle should be

protected by a membrane filter. Change filter

after collecting 10 samples.

5.1.4 Air-Pump. Capable of maintaining

a flow of 0.2 liter/minute through the absorber, and a vacuum of 0.7 atmosphere.

5.1.5 Calibration Equipment. Glass flowmeter for measuring airflows up to approximately 275 mL/min. within ±h2 percent,

stopwatch, and precision wet test meter (1

liter/revolution). -

5.2 Analysis.

5.2.1 Volumetric Flasks. 50, 100, 200, 250.

500, 1,000 ml.

5.2.2 Graduated Cylinder. 1,000 ml.

5.2.3 Pipets. 1, 2, 5, 10, 15 ml. volumetric;

2 ml., graduated in 1/10 ml. intervals.

5.2.4 Test Tube.

5.2.5 Spectrophotometer of Colorimeter.

Capable of measuring absorbance at 540 am.

Bandwidth is not critical.

6. Reagents.

6.1 Sampling.

6.1.1 Absorbing Reagent. Dissolve 4.0 -g.

sodium hydroxide in distilled water and

dilute to 1,000 ml.

6.2 Analysis.

6.2.1 Sulfanilamide. Dissolve 20 g. sulfanilamide in 700 ml. distilled water. Add.

with mixing, 50 ml. concentrated phosphoric

acid (85 percent) and dilute to 1,000 ml. This

solution is stable for a month if refrigerated.

6.2.2 NEDA Solution. Dissolve 0.5 g. N-1-

naphthylethylenediamine dihydrocbloride in

distilled water. This solution is stable for a

month if refrigerated and protected from

light.

6.2.3 Hydrogen Peroxide. Dilute 0.2 ml.

30 percent hydrogen peroxide to 250 ml. with

distilled water. This solution may be used for

a month if protected from light.

6.2.4 Stan4ard Nitrite Solution. Dissolve

sufficient desiccated sodium nitrite (NaNOz,

'Available from Bel-Art Products, Pequannbck, N.J.

RULES AND REGULATIONS

assay of 97 percent or greater) and dilute

with distilled water to 1.000 ml. s that a

solution containing 1.000 pg. NO mL L-- obtained. The amount of NallO2 to use C alculated as follows:

G= --- YZ 100

A

G=Amount of NONO:. g.

1.500=Gravlmetrlc factor in can'erting

NO, into NaNO.

A=Aszy, percent.

7. Procedure.

7.1 Sampling. Assemblo the -ampllng

train as shown In Figure Fl. Add 50 ml.

absorbing reagent to the absorber. Disconnect

funnel, insert calibrated flowmeter, and

measure flow before sampling. If flow rate

before sampling is less than 83 percent of

needle calibration, check for leak or change

filters as necessary. Remove flowmeter and

replace funnel. Sample for 24 hours from

midnight to midnight and measure flow at

end of sampling period.

7.2 Analys s. Replace any water lo3t by

evaporation during sampling. Pipet 10 ml.

of the collected sample into a te3t tube. Add

1.0 ml. hydrogen peroxide colution, 10.0 ml.

sulfanilamide solution, and 1.4 ml. NEDA

solution with thorough mixing alter the

addition of each reagent. Prepare a blank In

the same manner using 10 ml. absorbing

reagent. After a 10-minute color-development

interval, measure the absorbance at, 140 mm.

against the blank. Read pg. NO imL from

standard curve (Section 8.2).

8. Calibration and Eflciencies.

8.1 Sampling.

8.1.1 Calibration of Flowmctcr. Using a

wet test meter and a stopwatch, determine

the rates of air flow (ml./min.) through the

flowmeter at several ball pofitions. Plot ball

positions versus flow rates.

8.1.2 Calibration o1 Hypodermf N eedlc.

Connect the calibrated flowmeter, the needle

to be calbrxted, and the source of vacuum

in such a way that the direction of airflow

through the needle is the same as In the

sampling train. Read the position of the

ball and determine flow rate In mL/min.

from the calibration chart prepared In 8.1.1.

Reject all needles not having flow rate3 of

190 to 210 ml./min. before sampling.

ME1MRAtIE FILTER

&901

8.2 Calration Ctrre. Dilute 5.0 ml. of

the. 1,00 [g. NO7Jml. slution to 200 ml.

with absorbing regent. This solution contiln 23 pg. 1O;,ml. Pipet 1. ,5, and 15 ml.

of the 25 pg. NOJmL. solution into 50-, 50-.

100-. and 250-mi. volumetric flasks and dilute

to the mark with absorbing reagent. The

rolutions contain 0.50, 1.00, 1.25, end I0

pg. 170Oml., re--pecively. Run standards as

instructed in '7.2. Plot absarbance vs. -g.

8.3 Effle encCe3. An overall average effclency of 35 per cent v.-a obtained from test

atmnopheres having nitrogen dioxide concentratlons of 140 pg./m.2 and 200 g.fm.F by

automated analy3ls.(2)

9. Calculation.

9.1 Sampling.

9.1.1 Calculate volume of air ampled.

2

V=Volume of air ampled. m.2

F1=? easured floW rate before sampling.

Mi./mln.

P=Me in.ured flow rate after sampling.

T=Tlmo of ampling, mi.

10-= Convercion of mL to in.'

9.2 Caculate the concentration of nitrogen diodde a3 g. N1O,/m.

-,-~ r = (,g. NOj ml.) p450

(Ag. NOf ml.) 143

V

50 =Volume of absorblng reagent uzed in

sampling. ml.

V=Volumo of air smpled, m.

0,3=ElcIenc7.

9.2.1 If dezired, concentration of nitrogen

dioxide may be c3lculated as ppxm. NO.

p.mpM.=(g.NOfm) -5.32 X10-1

10. Ref ercn.ees.

(1) Jacobo, M. B., and Hochhelser, S., "Continuou3 Sampling and Ultramicrodetermination of Nitrogen Dioxide in

Air", Anal. Cl m., 30 420 (1953).

(2) Purdue, L. 3., Dudley, T. E.. Clements,

J. B.. and Thompoon, R. J.. "Studies in

Air Sampling for Nitrogen Dioxide,"

L A reinve tIgation of the JacobsHcchhelser ReaZent. In Preparation.

2_A FILTER

[1-.sa Fl. -. W18.

FEDERAL REGISTER, VOL. 36, NO. 14--FRIDAY, APRIL 30, 1971