I live in Los Angeles which is one of the most polluted cities the
nation. Much of this comes from car exhaust and industrial.  There are
other causes as well. I am looking for an portable air filter that
will elminate as much of this as possible. I have no allergies so that
isn't a concern.

This might seem like a simple request. The problem is that most of the
companies I have found upon close examination are almost fraudulent.

I am looking for you the following:
1. Be aware of the major types of air pollution that occur in los
angeles.
2. Be aware of the types of indoor pollution that occur. 
3. Find a system that addresses these. I want factual evidence. This
should not be based upon a pamphlet or a website alone. I want you to
reasearch this and give me a considered opinion. It seems like this
requires someone with a background in chemistry but I might be wrong.
I can read and discern these things myself. I want someone whose
knowlege is greater than my own. Thank you in advance for considering
this question.

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Request for Question Clarification by umiat-ga on 20 Jan 2003 13:37 PST

I am assuming that you want a portable air filter that you can take
with you, and use in various environments. Is this correct? Do you
also require a mask that you can wear on occasion? Do you have any
specific allergies? What type of environment do you work in? I ask
this because an awareness of "indoor pollutants" is a very broad topic
that covers a host of environments, from industrial work places to
hospital environments.

umiat

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Clarification of Question by cheaptrinkets-ga on 20 Jan 2003 15:05 PST

It doesn't need to be something I can take with me. Portable as
opposed to something that need to be installed. I don't mind if it is
large. It is for a residential and small office.

Secondly, please do not answer the question. In my question I state "I
have no allergies so that isn't a concern". If you can't take the time
to read my question I would rather you not answer it.

Thanks.

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Request for Question Clarification by umiat-ga on 20 Jan 2003 15:33 PST

I noticed that you did not have any allergies the second I clicked the
request button. I was going to add an additional clarification that I
had seen that and accidentally overlooked it.

 I have already done a significant amount of work on your answer.

 However, as you request, I will let all my work go and release the
question.

 umiat

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Clarification of Question by cheaptrinkets-ga on 20 Jan 2003 15:56 PST

It is up to you. To be honest, unless your answer is well thought out
and gives me new insights, I will request a refund.

Pafalafa certainly gave you an excellent response to your question!
 
 You specifically asked me not to answer your question. Therefore, I
thought I would at least comment on two companies that I believe are
worth considering in your quest for an air purifying system. Although
many portable air purifiers remove micro particles of tobacco smoke,
pollen and dust, when you are considering the wide range of pollutants
encompassed in the smog and pollution overlying a city such as Los
Angeles, which can also seep into a home or work environment, you want
a purifier that collects and screens out a much wider range of
pollutants. The types of air filtration/purifying companies which are
most applicable to the type of filtration you desire “might” be
companies which also manufacture industrial filtration systems, and
then offer consumer portable units as well.

  Air purifiers that offer good Hepa and Activated Carbon filters
screen out a wide range of pollutants. For that reason, you might
consider the following companies:

Sentry Air Systems 
http://www.sasairpurifiers.com/
 “We are a Houston based manufacturer of high quality floor, benchtop,
mounted and portable air purification devices. The company was
initially founded in 1983 as a distributor. Then in 1995, drawing on
several years of experience gained in the industry, we began
manufacturing this quiet and compact line of patented air cleaners
offering simple and unique air solutions for many laboratory and
manufacturing operations
 The company offers some portable consumer units under their “200”
Series.
   The Sentry 200 series offers the combination of Activated Carbon
and Hepa Filters. All models are portable and can been seen and
reviewed by clicking on the pictures at
http://www.sasairpurifiers.com/products.htm
  A chart showing the effective range of the Sentry Hepa Filter is
available at
http://www.sasairpurifiers.com/graph.htm 
A chart of Activated Carbon Absorption Ratings for the SAS system may
be reviewed at http://www.sasairpurifiers.com/carbon.htm

The Lydall Company offers a variety of filtration products from
manufacturers to consumers.
http://www.lydallfiltration.com/products_appl.cfm 
 If you click on the Consumer Air Filtration Products Tab, you can
read about the Lydair MG product for consumer applications:
 “LydAirŪ Consumer Filtration Grades are comprised of glass micro
fiber media, manufactured to the same exacting standards as Lydall’s
industrial grades. These specialty HEPA/ULPA grades have gained wide
acceptance in many consumer applications such as portable air
purifiers, home air conditioners and HEPA filters in vacuum cleaners.
The unit contains HEPA and ULPa filtration:
 LydAirŪ HEPA air filtration media are engineered for use in a wide
range of absolute clean air applications. These products are glass
micro fiber media with a range of air filtration efficiencies from
99.91 to 99.99 percent at 0.3 microns. LydAirŪ HEPA media can be
engineered to meet your specific applications
 LydAirŪ ULPA media provides end-users with maximum filtration
efficiency at low resistance, which results in improved processing,
and energy costs.
http://www.lydallfiltration.com/products_appl3.cfm?AID=26&CID=13


 A simple chart of the types of air filtering technologies can be
found on the CADR (Clean Air Delivery Rate) website at
http://www.cadr.org/consumer/air_cleaners.html

HEPA FILTERS
HEPA stands for High Efficiency Particulate Air, and like the name
says, these filters are
designed to remove 99.97% of all airborne pollutants 0.3 microns or
larger from the air that  passes through the filter (these include
tobacco smoke, household dust and pollen).

ULPA FILTERS
These ultra-HEPA filters are designed to trap 99.999% all air-borne
particles 0.3 microns or smaller from the air that passes through the
filter (these include tobacco smoke, household dust and pollen).

ELECTROSTATIC FILTERS 
Electrostatic units filter the air using static electricity have a
static charge on the filter to allow airborne particles to "stick" to
the filter, just like static-charged clothing sticks together.

ELECTRO-STATIC PRECIPITATORS
These air cleaners create opposite charges on the metal plates or
wires in a "filter" assembly. They attract the dust, pollen, smoke and
other particles to the plate or grid wire that contains an opposite
charge. The assembly can be washed of the particles and used again.

OZONE AIR CLEANERS 
These air cleaners introduce small quantities of ozone into the air to
reduce airborne pollutants.

IONIZATION 
Ionizers may be combined with other technologies, including different
types of filters. Ionization units emit a small charge to the
airstream which cause particles to adhere to the filter or other
surfaces by a magnetic-like attraction.

umiat