1. Aqueous Extraction of Filters for Determination of Anions in Ambient Air
Vanessa Mae Vergara
South Coast Air Quality Management District
6 June 2012
This Cooperative Education Report has been submitted to Solomon Teffera and has been
approved for release and submission to Dr. Gilbert R. Cadena, Cooperative Education
Director, Cal Poly, Pomona during the 10th week of the quarter.
Signed ________________________________________ Dated __________________

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Objectives:
The objective was to assist the chemists in the aerosols group, particulates group, and the
ambient monitoring group by preparing sampling media for sites, weighing samples,
performing data entry and performing data validating, as accurately and precisely as
possible.
Executive Summary:
South Coast Air Quality Management District (SCAQMD) is an air pollution
control agency for all of Orange County, parts of Los Angeles County, San Bernardino
County and Riverside County in South California. SCAQMD monitors for poor air
quality and works to reduce pollution if necessary in addition to performing product
testing, investigating odor complaints and more. I worked with the chemists in the
ambient monitoring group. They analyze and monitor what is already in the air from
fixed sites all over South California. Since the data are from fixed sites, new samples
come in about every six days. Because there are so many samples that come in within a
year, the Co-op company employer assists in preparing sampling media for sites. The
Cop-op employer assists with weighing samples, data entry, data checking, and also
performs the water extraction. The water extraction is executed to detect anions of
interest in the air that people breathe everyday, which are sulfate, chloride, and nitrate.
The Co-op employer position allowed me to learn about the way a lab is ran in a more
hands on method.
Description of the Co-op Position and Activities:
South Coast Air Quality Management District (SCAQMD) is an air pollution
control agency for a few counties in South California. SCAQMD monitors the air quality
in Orange County, Los Angeles County, and the western parts of San Bernardino and
Riverside County. Because SCAQMD supervises the air quality from different areas, the
pollution of air will vary from county to county. Some hazardous components that
SCAQMD looks out for in the air are metals, petroleum products, industrial emissions
and more. Different types of air pollution can cause anything from watery eyes to cancer,
like asthma, respiratory diseases, lung damage, birth defects, premature deaths and more.

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Due to the significant role that the air quality plays for a person’s health, SCAQMD
scouts for poor air and works to reduce pollution if necessary. As a Co-op company
employer, I work in the laboratory. Specifically, I am working in the ambient monitoring
group. Once the sample is received, the chemists analyze the data from the sample and
look for harming anions. They analyze and monitor what is already in the air from fixed
sites all over South California. Since the samples are from fixed sites, they come in, at
most, every six days. Because there are so many samples that arrive in a year, the Co-op
company employer assists in preparing sampling media for sites, weighing samples,
performing data entry, performing data validating, and performing water extractions for
anion analysis.
Description of Project(s) Completed and Data:
To obtain data, one needs to go through various steps before performing a water
extraction. Various samples arrive from fixed sites. At these sites, there are machines that
draw in air for 24 hours. The chemists analyze filters from the samples. There are two
different groupings of samples that the Co-op employer works with, Total Suspended
Particulates (TSP) and Particulate Matter (PM10) 10 microns or smaller. The difference
between the two is that when analyzed, the TSP filters looks at everything in the air,
whereas the PM 10 focuses on the smaller particulates. These filters are used for different
analysis. The Co-op employer assists with preparing both the filters.
The experiment first started by obtaining a box full of either TSP or PM 10 filters,
which varied on which the site and operator needed at that specific time. Within the box
there were about 60 filters, and each filter needed to be carefully examined. Each filter
needed to be checked for any discoloration, holes, lines, or any other factors that would
sway the results of the analysis. The filters were checked by a light inspection. Carefully
placing the blank filters on a light table (with gloves), allowed for a clear observation of
the filters. If the filter did not contain any serious distortions, it was suitable to go back to
the box and be used, but if there was any major type of defect the filter would be
considered a reject and removed.
After each box was checked, the next step was to make filter packets. These filter
packets were to be sent out to each site for sampling. The filter packets were made by

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carefully picking up each filter with gloves, placing it on an analytical balance, and
recording the weight in grams in a record book. After ten filters were weighed, it was
important to go back to the first filter and reweigh it to get a quality control (QC) value.
Because the room was at a fixed temperature and humidity, the QC was important to
make sure the room was in the same fixed conditions. After the ten filters were weighed
each filter needed to be packed into a manila folder starting with 5 pieces of card stock
paper on top, followed by one filter and one sheet of computer paper, repeated ten times,
followed by another 5 pieces of card stock paper on the bottom. After the filters were
weighed, recorded in the book, and placed into a folder, they needed to be recorded on
the computer.
Once the data was all entered into the system, another employer had to double-
check the work to make sure everything was accurate. Verifying data was an important
step to catch any little mistakes while imputing the data on the computer. As each packet
is verified to be 100% correct, the packet is ready for the site.
When the filters returned, each filter was individually packaged. Upon the return
of each filter, they needed to be conditioned. This was necessary because they were sent
off to different areas. For example, a filter from Palm Springs would be drier than the
Long Beach filter due to the humidity or dryness from each area. Conditioning the filter
at a constant temperature and humidity for 24 hours returned the sample back the original
moisture level. This caused the results of the mass value to be more accurate.
The next step was to take the final weight of each filter in groups of ten. The same
procedure for weighing was performed for both the tare and final weights, with one
exception, the final value was written directly on the packet that the filter was in. This
step was repeated ten times until there were ten filter packets for one batch. After the
tenth filter packet was made, like the initial weight, it was important to go back to the
first sample and reweigh it again to get the QC value. The QC value needed to be about
0.001 from the first weight. If not, a supervisor needed to be informed immediately.
After the final weight, the data again needed to be recorded into the computer
system. Another employer would then verify the work, and if anything did not need to be
fixed, then the next step was to perform a water extraction. All the previous steps were
completed to obtain and prepare for the water extraction. The water extraction verifies

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how much chloride, nitrate, sulfate are in the air by using the filters. This information is
important because these anions are smog-forming ions and also can be a health risk.
Since there are other analyses done to the filters besides the water extraction, only
a quarter of the filter is needed for the water extraction. In order to obtain a quarter, the
filter needed to be precisely cut. Again, gloves needed to be worn when handling the
filters. Since the filters were handled more with our hands during the cutting process,
gloves needed to be washed prior to cutting. Gloves needed to be rinsed off with
deionized water because although the gloves can contain mild amounts of ions, it was
still enough to sway the results. By rinsing off the gloves it can remove some of the
anions on the gloves.
Based on the samples edges, not the filter paper’s edges, cutting the filters needed
to be folded vertically first. Then, the sample needed to be folded and cut horizontally
and then a quarter of the filter paper should be left over. After the quarter of the sample is
left over, that quarter would then be cut into smaller pieces to fit inside an Erlenmeyer
flask and the excess of the sample would go back into the packet for other analyses. After
the task was repeated 24 times per batch, the matrix spike was added to one of the cut
filters. Within the 24 filters that are in one batch, there were three different Quality
Control samples. The QC samples were a blank, duplicate, and a matrix spike. The blank
tested for the cleanliness of the process, filter, solvent, (which was water), and the
materials. The duplicate tested for how precise the extraction was based on its numbers
and how reproducible the number was based on the other sample. The matrix spike adds a
known quantity of the analytes of interest and tests for matrix effects. Since the water
extraction tested for nitrate, sulfate, and chloride, the matrix spike consisted of 950 ppm
of nitrate and sulfate, and 500 ppm of chloride.
After, 100 mL of deionized water was then added to each of the Erlenmeyer
flasks. Then the Erlenmeyer flasks were placed on an orbital shaker table for at least an
hour so the solvent could extract the anions. While the samples were mixing, it was best
to set up bottles underneath a clean funnel with a filter paper so the solution could drain
into the appropriate bottle. The filter was used to stop the excess sample paper from
getting into the extract solution. After at least an hour on the orbital shaker table, the
solution needed to be poured into the funnel and into the bottle. After all the solutions

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were drained into a bottle, the bottle was capped and placed in order so another chemist
can run the analysis to verify how much nitrate, sulfate, and chloride were in the air.
Suggestions For Further Work, New Objectives, and Action Required
My original objective was to experience hands on learning in a lab, and I felt that
after this Co-op position, I achieved my objective. A new objective I would like to
accomplish during my next Co- op term, would be to further my knowledge and really
focus on the chemistry and data that is analyzed at SCAQMD. I believe I am ready to
take on any other responsibilities and duties that my supervisors can challenge me with.
Personal Comments
SCAQMD was a great environment to learn and work. Because the district was
under the government, the management and staff were rarely stressed. Due to the fact that
there were not usually clients that needed data information right away, it allowed for the
team to work at their own pace and most importantly be precise and accurate with their
results.