LaMotte Air Pollution Sampling - Measurement User Manual

Air Pollution

Sampling

&

Measurement

Instruction Manual

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TABLE OF CONTENTS

How to Establish a Meaningful Air Monitoring Program ..................... 3

Equipment Requirements ........................................................... 3

Establishing a Sampling Site ...................................................... 5

Air Sampling Apparatus:

Air Sampling Pump ....................................................................... 7

Instructions ............................................................................... 7

AC Operation........................................................................... 9

Battery Replacement .................................................................. 9

Maintenance of Flowmeter ......................................................... 9

Storage.................................................................................... 9

Hand Operated Syringe Pump ..................................................... 10

Instructions ............................................................................. 10

Conversions ............................................................................... 11

Flow Equivalents ......................................................................... 11

Combination Air Pollution Test Kits ................................................ 12

Individual Air Pollution Test Kits ..................................................... 13

General Precautions ................................................................... 14

Packaging & Delivery ................................................................... 15

Limits of Liability ......................................................................... 15

2 Air Pollution Sampling & Measurement

HOW TO ESTABLISH A MEANINGFUL
AIR MONITORING PROGRAM

To set up a program for monitoring air pollution there are two basic
requirements. First, a means of collecting and analyzing the air sample is
required. Second, a strategic plan for continuous sampling at a series of
logical monitoring sites must be established. The recording of data over
a period of time is important in observing the variations that take place
at the monitoring sites.

EQUIPMENT REQUIREMENTS

Most of the sampling in air pollution studies is done with some type of
vacuum equipment. The vacuum is required to draw an air sample
through a chamber holding a special absorbing solution. The absorbing
solution is chemically selective for a particular gas, and is held in a
special glass bubbling tube called an impinger. Since gaseous pollutants
differ chemically, the absorbing solutions are also different.

In order to make a quantitative test, a means to measure the amount of
air that is drawn through the absorbing solution has to be known. This is
done by the use of an adjustable flowmeter. A flowmeter is simply a
device to measure the rate of flow of the air through the absorbing
solution. For most air pollution studies the flowmeter is calibrated to
measure the rate of flow in liters per minute (Lpm).

When a flowmeter is attached to the vacuum portion of the air sampling
train, one can accurately monitor the amount of air which is pulled
through the absorbing solution. A flowmeter with an adjustable flow
device - like a needle valve - can be used to preset the vacuum pump to
sample at a known rate. If one draws air through the absorbing solution
at 2.0 Lpm for 10 minutes, then 20 liters of air have been sampled.

As one of the most important components of the air sampling train, the
vacuum pump must meet certain requirements. If one is interested in
taking air samples from outdoors, the vacuum equipment must be
battery operated and completely portable. It should also possess a
means for regulating the amount of air sampled. Vacuum equipment
meeting these criteria would be useful for most applications. Air pumps
that push the air through the pump first and then through the impinging
equipment should be avoided. Proper sampling techniques require that
the air sample be “sucked” through the impinger prior to its contact with
the pump. The pump should have the ability to maintain a particular
flow rate for a pre-determined time. Air sampling equipment should be
completely portable, possess a regulating device for sampling at
different rates, and be able to maintain a particular sampling rate for a
known amount of time.

Air Pollution Sampling & Measurement 3

Impinger devices are available in various shapes and sizes. The simplest
impinger device consists of a glass vial plus a stopper with a short glass
tube and a longer glass tube. The long tube is immersed into the
absorbing solution. Other types of impingers are more sophisticated and
may meet the specifications set forth by the American Public Health
Association or some other regulatory agency.

In principle, the inexpensive impingers and the precision impingers
operate in a similar fashion. Some precision impingers have a fitted
glass end which is immersed into the absorbing solution. This enables
the impinger to disperse many minute bubbles. The smaller the bubbles,
the more surface contact is permitted between the gas and absorbing
solution and a higher efficiency of gas absorption results. A fritted glass
bubbler of this description is used for nitrogen dioxide determinations.
For other determinations, a plain glass bubbler assembly is used which
usually has a 1 mm opening at the end for dispersing the air sample into
the absorbing solution.

The individual chemical test modules used to analyze the absorbing
solution after impingement are based upon established methods for
testing air pollutants. For convenience and portability these testing units
are furnished in compact carrying cases. All of the necessary apparatus
and reagents needed to conduct a chemical analysis of the air are
included within the testing outfit.

The reagent systems included in the testing units include an absorbing
solution which extracts the chemicals from the atmosphere. In some
systems a single indicator is added to the absorbing solution to cause a
color reaction. In other systems, the absorbing solution is pre-treated
before the indicator is added. The color reaction is measured in a visual
comparator or an electronic colorimeter.

Visual comparators are devices for matching the color of the test sample
to color standards of known value. Each comparator contains eight
permanent color standards. The color standards have an index,
numbered one through eight. The number refers to a calibration chart in
the instructions for each test. After the recommended testing procedure
is completed for a particular test, note which index gave the proper color
match and refer to the calibration chart.

Regardless of whether the air pollution test equipment is used for testing
air pollution levels in confined areas or for monitoring atmospheric
pollutants in the field, significant results are obtained only if correct
analytical techniques are used. Clean glassware and uncontaminated
reagents are important for accurate results. Sampling apparatus should
be checked periodically to insure proper operation.

4 Air Pollution Sampling & Measurement

Some of the reagents require special handling as they are capable of
causing skin irritations. No chemical reagent should be taken internally,
but if accidentally ingested, heed the antidote label on the bottle and
contact a physician immediately. Reagents which are marked poison
should be treated as such. Careful handling of all chemicals is a
necessary part of chemical testing. Follow all instructions as outlined in
the individual directions for each test.

ESTABLISHING A SAMPLING SITE

To establish a meaningful air pollution monitoring program, one must
take a complete survey of the area and prepare a sampling map to
select a sampling site. Consider which sources might be responsible for
contributing to air pollution. Where are these sources? Determine
whether pollution control devices are being used and whether these
devices are operating correctly. Heavy industrial areas contribute
significantly to the total pollution in an area. Determine what tests should
be used to accurately monitor industrial emission.

When recording data on sampling, take into account meteorological
data such as the prevailing winds, temperature inversions, rainfall and
other factors which affect the dispersion of air pollutants. Try to set up a
remote sheltered location away from the normal air pollution sources or
a control for comparison purposes.

Another significant source of air pollution is the automobile. To
familiarize you with how each car contributes to air pollution, check the
emissions from a single car. Compare new cars with emission control
devices to older cars with limited or no emission control devices.
Determine what major pollutants are emitted from the exhausts of other
internal combustion engines, e.g. lawn mowers. The exhausts from
internal combustion engines are poisonous. Never work in confined
areas without adequate ventilation. Work with proper supervision.

Locate the traffic laden roads of your community during rush hour.
Compare the amount of pollution with the number of cars at different
times. Compare results of tests to data compiled during non-rush hour
traffic conditions. How may these pollutants be dispersed by
meteorological conditions?

For classroom studies and to familiarize students with the chemical
procedures it may be necessary to demonstrate the basic principles of
collecting and measuring air pollution factors. Certain gaseous
pollutants such as ammonia, chlorine, and total oxidants are easily
demonstrated because of the simple chemical procedure involved and
also because these gases are readily available as household or standard
laboratory supplies — ammonia cleaners, bleach, hydrogen peroxide,
etc.

Air Pollution Sampling & Measurement 5