Your throat is sore, you are tired all the time, and you have a lingering
cough that won’t go away. You’ve been tested for flu, COVID-19, and strep
throat, and the results come back negative. Yet it doesn’t feel like a cold
either. Perhaps, then, it’s your indoor air quality (IAQ).
Indoor air is subject to contaminants that may cause symptoms ranging from sniffles to more
serious (and sometimes fatal) results. Wouldn’t it be nice to know what you
are breathing in?
Fortunately, it is possible to test for types of
contaminants in your space. Let’s begin by discussing what contaminants can
be in your air, and when to test for them. At the end of the article, we’ll
explore different testing methods you may use.
Please note that we are air quality experts, not doctors or lawyers. Nothing in this article may be
construed as medical or legal advice. Our goal at ActivePure is to raise
awareness of the importance of air quality and encourage you to improve your
IAQ with the methods that work best for the needs of your home, school,
facility, or business.
Types of contaminants & when to test
For the purposes of this article, we split indoor air pollution into five broad,
unofficial categories:
- Combustion gases
- Volatile organic compounds
- Biological contaminants
- Particulate matter
- Miscellaneous contaminants
Combustion gases
Gas stoves release many contaminants, including combustion gases. Combustion
gases are exactly what they sound like: gases associated with the
combustion of fuel. Carbon dioxide, carbon monoxide, and nitrogen dioxide
are three important examples.
Carbon dioxide:
Carbon dioxide is an odorless, colorless gas with the formula CO2.
- Source: Your own lungs pump carbon dioxide into the air constantly. CO2
may also be produced by any source of combustion, such as a heater or
stove. Since CO2 is the fourth most common gas in the atmosphere, this
usually isn’t much of a concern. However, modern buildings are often
built to be as airtight as possible for energy efficiency. This can
spike carbon dioxide to undesirable levels. - Standards: According to the Wisconsin Department of Health, negative
effects of carbon dioxide can be perceived in concentrations above 1,000
ppm (parts per million). The normal level for outdoor air is 400 ppm. - Indications of high carbon dioxide: The main indication of high carbon
dioxide is drowsiness, (but come on, when are you *not* tired; life is
busy). One recent study demonstrated that concentrations of 1,000 ppm
can also impair people’s ability to perform cognitive tasks. At 2,000 to
5,000 ppm people may also experience headaches, increased heart rate,
and nausea. - When to test: If you are in an old, drafty building, you can be fairly
certain that the indoor and outdoor air are circulating sufficiently to
prevent CO2 buildup. However, modern buildings (unless they have an
Energy or Heat Recovery Ventilator built into the HVAC system) might bear
testing, especially if you are experiencing symptoms.
Carbon monoxide:
Carbon monoxide is carbon dioxide’s evil twin, with a chemical formula of CO.
- Source: Carbon monoxide can be produced by any sort of combustion. It can
reach dangerous levels when a heating system or stove is either installed
improperly, is venting improperly, or is damaged. CO can also accumulate
when attempting to do something foolish, such as trying to operate a
grill or a portable generator indoors. - Standards: Normal levels (in houses with gas stoves) range from 0.5 to
five ppm. OSHA standards limit carbon monoxide to 35 ppm over a 10-hour
shift for workers. People with heart problems may experience chest pains
if CO levels are between 1.0 and 70 ppm. If you don’t have heart
problems, symptoms generally won’t appear until the concentration reaches
above 70 ppm. Levels above 150 ppm may be fatal for healthy adults. - Indications of high carbon monoxide: Death. Before you die though, you may experience blurred vision, nausea, headaches, dizziness, confusion,
and loss of consciousness. By the time carbon monoxide poisoning becomes
obvious, you may be too drowsy and/or confused to vacate the area. It
should be noted that carbon monoxide is also especially dangerous for
children in utero. - When to test: Always. Carbon monoxide is the sort of contaminant which
requires 24/7 monitoring; (see the section titled ‘Household monitors’
below). It would also be wise to have your fuel-burning appliances
inspected annually.
Nitrogen dioxide:
Nitrogen is the most common gas
in the earth’s atmosphere, and is relatively harmless. When combustion
occurs, however, it can react with oxygen to form a family of gases known
as nitrous oxides. We are most concerned with nitrogen dioxide
(NO2), which is a reddish-brown gas with an acrid smell.
- Source: NO2 can form due to any type of combustion, especially gas or
kerosene stoves and heaters. - Standards: The World Health Organization recommends keeping indoor
Nitrogen Dioxide levels at five parts per billion (ppb). Cooking with a
gas stove can generate levels many times this in a poorly ventilated
kitchen. - Indications of nitrogen dioxide: Nitrogen dioxide can inflame airways,
reduce lung function, and trigger asthma attacks. It might also worsen
coughs and increase your risk of an emergency room visit. There are some
indications that it might even cause asthma in young children. - When to test: If you are a parent with young children or are an adult with
lung ailments, it might be wise to test your nitrogen dioxide levels,
assuming you have a gas stove or combustion-based space heater.
Volatile organic compounds (VOCs)
Rugs and new furniture may off-gas VOCs.
Volatile organic compounds are water-soluble and carbon-based. They are
exuded as gases by everything from carpets to chemical cleaners. One common
VOC is formaldehyde, although there are many others.
Formaldehyde:
Formaldehyde is a pungent, colorless gas with the formula CH2O. It is also a
carcinogen.
- Source: The main source of formaldehyde in homes is
pressed wood. Other
sources can include dry-cleaned clothes, certain hair treatments, tobacco
smoke, and combustion. - Standards: Average levels are 0.1 ppm in the home but can range up to 0.3
ppm. OSHA standards indicate a limit of 0.75 ppm for workers in an 8-hour
shift. - Indications of high formaldehyde: Indications of high formaldehyde can
include watery eyes, coughing, wheezing, nausea, and skin irritation.
Formaldehyde may also cause burning sensations in the eyes, nose, and
throat. - When to test: Formaldehyde degrades quickly, but it might be worth
testing in newer homes with a significant amount of pressed wood
products. It also should be tested in workplaces that produce a high
level of VOCs, such as dry cleaners, salons, or factories.
Particulate matter:
Particulate matter is “a mixture of solid particles and liquid droplets found in the air.” Particulate matter is classified by size, so PM10 refers to particles of roughly 10 microns or smaller, PM2.5 refers to particles 2.5 microns or smaller, etc. In general, the smaller the particulate matter, the deeper it can penetrate the lungs and the more dangerous it is.
- Source: Everything from pet dander to pollen, tobacco smoke to
smokestacks, bacon to beach sand contributes to particulate matter. Many
causes of air pollution such as forest fires and factories are also
sources of particulate matter. - Standards: There are no indoor standards for particulate matter. The
current ambient standard for outdoor PM2.5 is 12.0 micrograms per cubic
meter (µg/m3) as an annual average. The outdoor standard in any 24-hour
period is 35 µg/m3. - Indications of high particulate matter: Long-term exposure to particulate
matter can be dangerous even when there aren’t any obvious immediate
effects. Per the EPA, prolonged exposure to particulate matter can cause “premature death in people with lung and heart disease, nonfatal
heart attacks, irregular heartbeat, and decreased lung function over
time.” More immediately, it can “aggravate asthma, irritate airways, and
cause coughs or difficulty breathing”. - When to test: Outdoor particulate matter is easy to test for any time you
like; just check the air quality report in your area. Because indoor
sources (such as a stove) can spike levels even higher than the outdoor
level, it’s wise for everyone to monitor this contaminant indoors to see
if action needs to be taken.
Biological contaminants
Biological contaminants include fungi (mold), bacteria, and viruses.
Fungi (mold & mildew):
Fungal spores exist everywhere you look, and it is
neither practical nor desirable to eliminate them entirely. However,
aside from the yeast in your sourdough starter, you generally don’t want
to encourage fungal growth indoors. Undesirable indoor fungal growth is
usually called mold or mildew. Informally, these terms are applied
interchangeably. Officially, though, mildew is a type of mold, so we will
be referring simply to “mold” for the rest of this article.
- Source: Wherever there is sufficient moisture indoors, fungal spores can
stick to surfaces and begin to multiply. Most molds also prefer warm,
dark places. For these reasons, bathrooms and basements are of particular
concern. - Standards: Per the EPA, “Currently, there are no EPA regulations or
standards for airborne mold contaminants.” - Indications of mold: Mold exposure can produce allergy-like symptoms such
as sore throat or skin rashes. Despite fear-mongering over the
dreaded “toxic mold syndrome”, there is no evidence of so-called “black
mold” producing memory loss, headaches, fatigue, or infantile pulmonary
hemorrhage. Mold exposure is, however, associated with asthma in
school-age children. Certain molds may also infect the lungs of the
immunocompromised.
Viruses and Bacteria:
- Sources: Bacteria are nigh-omnipresent, microscopic organisms. Most
bacteria are either beneficial or harmless. It’s impossible to get rid of
all bacteria, nor should you try. The goal is to prevent the development
of infectious pockets of harmful bacteria, such as legionella or
tuberculosis.Viruses are packets of DNA or RNA encased in a protein
shell. They take over other cells and force these cells to produce more
viruses. Viruses are shed by any living things infected with that same
virus, (i.e., they are shed by infected humans or animals). In this
section we are concerned with viruses which can infect humans through
exhaled aerosol droplets, such as influenza A and SARS-CoV-2. - Indications of high bacteria or virus count: Unless you are already sick,
it’s hard to tell without testing. However, as bacteria and viruses may
travel inside particulate matter, particulate matter may be an indirect
indication of unhealthy air pathogen levels. - Standards & when to test: Most field testing does not measure the
concentration of a particular bacterial or viral pathogen. Instead, it
merely indicates if a particular variety of pathogen is present. For this
reason, the main air quality “test” recommended by the EPA for biological
contaminants is to inspect general sanitary conditions in the building.If you are concerned about viruses and bacteria in your home,
(either because you have frequent guests or you are immunocompromised) we
recommend researching active air purifiers.We believe businesses, schools, and hospitals will still wish to test viruses and bacteria as
part of testing their general air quality and ventilation effectiveness.
They also may want to test their pathogen levels on surfaces, especially
where food is prepared.
Other miscellaneous contaminants
Damaged, flaking paint is the main source of lead dust.
Lead dust:
- Source: Lead dust generally comes from scraping, peeling, or damaged lead
paint. While lead paint is no longer used in the U.S., it can still be
found in older buildings. - Standards: Per the EPA “new clearance levels are 10 micrograms (µg) of
lead in dust per square foot (ft2) for floor dust and 100 µg/ft2 for
window sill dust.” You’ll notice neither of these are airborne levels.
This is because lead dust mainly enters the air from activity around
damaged lead paint. All lead testing methods we are aware of are for
surfaces, not air. - Indications of lead poisoning: It generally takes a long time for lead to
build up to the point that poisoning is noticeable in adults. According
to the Mayo Clinic, symptoms can include high blood pressure, joint and
muscle pain, memory and concentration problems, headache, abdominal pain,
mood disorders, and reduced sperm count. It may also cause “
[m]iscarriage, stillbirth or premature birth in pregnant women.” Per the
EPA, “Lead exposure in children can result in delays in physical
development, lower IQ levels, shorter attention spans, and an increase in
behavioral problems.” - When to test: When you live in a building constructed before 1978 AND a)
there is peeling paint, b) you have children, OR c) you are about to do
repairs, construction, or renovation, you should test for lead on the
relevant surfaces.
Radon:
Radon is an odorless, colorless, radioactive noble gas.
- Source: Radon is generated from the decay of radioactive elements in rocks
or soil. - Standards: The EPA recommends that “homes be fixed if the radon level is
4 [picocuries per liter (pCi/L)] or more. Because there is no known safe
level of exposure to radon, the EPA also recommends that Americans
consider fixing their home for radon levels between 2 pCi/L and 4
pCi/L.” - Indications of high radon: The main indication of high radon is lung
cancer. We don’t recommend waiting for this indication. - When to test: The EPA recommends testing all homes below the third floor every two years. If high radon levels are found, testing should occur
again after mitigation to make sure the problem is fixed.
Asbestos:
Asbestos is a term used for any one of six fibrous, heat-resistant
minerals. Because these minerals are so versatile, they were once used in
everything from paper to paint to tiles to insulation. Asbestos materials
are not technically banned in the U.S., but they are highly regulated.
- Source: Since asbestos is naturally occurring in the ground, we all
breathe in a small amount
of asbestos each year. However, excessive
asbestos exposure can occur when materials made with asbestos are
damaged (such as during construction or renovation). With sufficient
asbestos exposure, a person may develop specific cancers such as
mesothelioma or other fatal lung issues. - Standards: OSHA’s permissible exposure limit for asbestos is “0.1 fiber
per cubic centimeter of air as an eight-hour time-weighted average.” - Indications of asbestos: Like radon, by the time you have a physical
indication of excessive asbestos exposure, it’s already too late. - When to test: Materials in old buildings should be tested for asbestos
before renovation or construction. You will also want to test damaged
building materials (such as decaying pipe insulation) before attempting
repairs. Air tests for asbestos are only required after an asbestos
abatement. You might also wish to test asbestos if you live near a
naturally occurring asbestos deposit.
How to measure internal air quality (IAQ)
Some forms of air quality testing rely on laboratory analysis.
Now that we know different types of contaminants and when to test for them, let’s discuss how to test for them. There are seven methods of IAQ testing. Note: For this section, we are especially indebted to the EPA’s “Common IAQ Measurements – A General Guide”.
The ‘smell test’
No single test checks for every possible pollutant. Before you invest in professional testing, you’ll
want a general idea of what you are testing for.
The easiest way to get this general idea is to use all your senses (including your common sense). If you are sniffling and sneezing, it’s likely you have some type of allergen. If you see peeling paint, you might have lead dust. If you smell mold, you probably have mold. Of course, many contaminants, including some of the most dangerous ones, are not immediately identifiable. Many symptoms, such as lethargy or a cough, may be caused by a variety of contaminants. For this reason, you’ll also want to use one of the
more targeted methods of testing below. However, your senses and your symptoms can provide you with a strong starting point.
Advantages of the ‘smell test’
- This method costs you nothing but time. H4Disadvantages of the ‘smell
test’ - This method is highly subjective and thus potentially inaccurate.
Indirect testing: air flow, temperature & humidity
Some of the most important testing doesn’t look for contaminants at all, but judges
whether contaminants might be building up. Because modern buildings are
built to be airtight, well-designed and well-maintained ventilation
systems are essential for healthy indoor air quality.
Temperature and
humidity analysis may be used to determine the efficacy and functionality
of your current HVAC system. Meanwhile, a smoke (or fog) generator, which
releases puffs of chemical smoke, may be used to map airflow movements
and ventilation in a space. A pitot tube or anemometer can measure air
velocity to help determine air exchange rate. Taken together, these
methods can indicate if a building’s ventilation is encouraging or
preventing healthy indoor air quality.
Advantages of indirect testing
- Reveals ventilation/HVAC problems which could contribute to poor IAQ.
H4Disadvantages of indirect testing - Indirect testing doesn’t reveal specific contaminants.
Targeted testing kits
Some contaminants may be tested with one-use home air quality test kits. These fall into two categories: DIY or lab analysis.
DIY kits usually contain various materials and reagents designed to show
you the presence of a specific contaminant. For instance, lead may be
tested for with a color-changing pen filled with two reactive chemicals.
Mold test kits might contain a petri dish with a dextrose (sugar) solution; this is designed to grow mold rapidly if spores are present. One dust mite kit attaches to your vacuum, and shows
pregnancy-test-esque lines at the presence of dust mite allergens.
(Please note that ActivePure has not vetted any of these products and
therefore can neither endorse nor condemn them.)
Laboratory analysis kits allow you to collect the sample, though that sample must be sent to
a lab for analysis. ActivePure’s partner Allergy Buyers Club carries an
entire range of such home test kits for contaminants of every possible
kind—from fungi to formaldehyde to fiberglass, and everything in between.
Advantages of targeted testing kits
- For DIY kits, you are provided with near-instant results. For lab-based
kits, you have the advantage of a professional option without needing to
schedule an appointment.
Disadvantages of targeted testing kits
- Most targeted kits only test for one type of contaminant.
- Contaminants can ebb and flow in a space based on cooking, painting,
construction, people in the room, weather, and ventilation. Sample kits
only capture one moment in time. That is, they only tell you what the
contaminants’ presence was like at the time you tested. - Targeted testing kits are single use, meaning you only get one shot per
testing material. Because you are performing the test yourself, there is
plenty of room to make an error. (Some kits include extra supplies
partially for this reason.)
Broad-spectrum sampling
A lab technician analyzes samples under a microscope.
It’s often best to have an idea of what
contaminant you are testing for ahead of time. However, if you are looking to
take a general sample of your air quality, here are two popular options.
One method is the detector tube kit, which collects an air sample in a sealed
tube; (before reading this article, we bet you never imagined a scenario
where you would have to literally mail air).
Another popular method of lab-based analysis is the vacuum pump. Per the EPA, a vacuum pump “draws air
through collection devices, such as a filter (catches airborne particles), a
sorbent tube (which attracts certain chemical vapors to a powder such as
carbon), or an impinger (bubbles the contaminants through solution in a test
tube).” One of the most common types of filters is known as the sampling cassette.
If you grew up in the ‘90s, allow us to clear away any confusion.
These cassettes have nothing to do with ribbon tapes untangled by a pencil
eraser. Air sampling cassettes are enclosed plastic chambers with holes on
either end. An air pump is connected to one end of the chamber, and air is
drawn through at a specific rate in liters per minute. Contaminants stick to
an adhesive medium inside the cassette. The consumer then sends this cassette
to a lab.
At the lab, the contaminants collected are stained and put under a
microscope at various magnifications. The contaminant count on the sample is
used to estimate contaminants in the air.
Advantages of broad-spectrum sampling
- Vacuum pumps and detector tubes may test for a wide spectrum of
contaminants. H4Disadvantages of broad-spectrum sampling - Vacuum pumps need to adjust the sample time based on the humidity and
perceived cleanliness of the environment you are testing. - Like DIY testing, broad-spectrum sampling only captures the air quality of
one moment in time.
Handheld detectors
These are electronic devices not entirely unlike a scanning device from a science-fiction show. They
measure such things as temperature, formaldehyde, carbon dioxide,
humidity, particulate matter, and total VOCs. Handheld detectors contain
dedicated sensors for each contaminant. For instance, they measure
particulates by shining a laser on a sensor and measuring the amount of
interference.
Handheld detectors are most often used by IAQ
professionals, but they don’t take a great deal of expertise to learn.
You can purchase one online for anywhere between $100-$1,000 dollars.
Advantages of handheld detectors
- Because they are so mobile, handheld detectors are excellent for
pinpointing the source of contaminants. - Unlike test kits, handheld detectors are multiple-use devices. They also
test for a wide range of contaminants.
Disadvantages of handheld detectors
- While a handheld detector provides real-time information, it is not
designed for continuous monitoring. - Handheld detectors sometimes require calibration, that is, testing a base
level in uncontaminated (usually outdoor) air. - As of 2014, the EPA did not believe that direct reading (such as that from
a handheld monitor) yielded useful results with regards to VOCs, but they
did believe it could identify hotspots.
Household monitors
Note that some detectors monitor both smoke and carbon monoxide.
Household monitors can either be dedicated to a single contaminant or test for
a broad range of contaminants. You likely already have two single-contaminant
detectors in your home: a smoke alarm and a carbon monoxide detector. If you
don’t, install both on every floor of your home (plus one smoke detector in every bedroom).
Broad-spectrum monitors test for many of the same factors as
handheld monitors.
Advantages of household monitors
- Monitors provide round-the-clock analysis in real-time. Unlike handheld
monitors, you don’t have to carry them around the house while staring at
them. Instead, they either make a sound or send a report to your smart
phone.
Disadvantages of household monitors
- Broad-spectrum monitors tend to be the priciest of the DIY solutions.
- Some household monitors require calibration.
Call the professionals
DIY kits for each type of contaminant?! Monitors that send real-time data to
your phone?! Mailing samples to labs?! Yikes, you have an overwhelming
number of options.
If you think it’s all a bit much, which not call in
the cavalry? ActivePure’s partners—which include Aerus, AES, and
Vollara—can provide a whole range of testing based on your unique space,
concerns, and needs. This may include any of the following: swabbing
surfaces for pathogens, measuring particulate matter in your indoor air,
analyzing your ventilation system, and/or taking comprehensive air
samples. They can then create a customized plan to ensure the highest
indoor air quality in your home, school, healthcare facility, or
business.
Advantages of a professional visit
- You’ll receive accurate, thorough results, as well as a customized plan of
action without having to purchase and operate different test kits
yourself.
Disadvantages of a professional visit
- A professional visit does not provide real-time monitoring.
It can be reassuring to have a professional team analyze your air quality.
To summarize:
Your own senses
and indirect airflow analysis are great for getting an idea of what to look
for. DIY and lab kits can tell you what your problems are, mobile detectors
can tell you where the problems are coming from, and home monitors keep an
eye on things day-to-day. Meanwhile, a visit from an authorized ActivePure
distributor can help you develop a customized IAQ plan.
Now you have a general idea of the contaminants that affect your air quality and how you can
test for them. We hope this guide is helpful in developing strategies for
improving indoor air quality in your home, hospital, business, or school. If
you want assistance in developing these strategies, please click the button
below to be put in touch with an IAQ expert.
