Category: Indoor Air Quality

Air Pollution in Energy Efficient Homes

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Air sealing the building envelope is one of the most critical features of an energy efficient home.  As new homes grow increasingly tighter to achieve ever higher levels of energy efficiency, the potential for indoor air pollution also increases.

Modern Construction

During construction, there are hundreds of penetrations through a typical home’s exterior. These gaps and holes are often incurred during framing, and from penetrations for wiring, plumbing, and ducts.  Air leakage accounts for 25–40% of the energy used for heating and cooling in a typical home.  To make a home energy efficient, these gaps and holes are closed and insulated to prevent the loss of conditioned air.

Indoor Air Quality Concern

Good indoor air quality is achieved by reducing or eliminating sources of indoor air contamination and providing sufficient fresh air through the heating and ventilation system.  While older homes were not energy efficient, they typically did not have problems with indoor air quality because they allowed for fresh air to freely circulate within the home.

As new homes grow increasingly tighter to achieve ever higher levels of energy efficiency, potential indoor air pollution also increases since many conventional building materials emit volatile organic compounds like formaldehyde.  While energy efficiency is important, gains in energy efficiency, especially in new homes, should not come at the expense of deterioration of indoor air quality and corresponding adverse health impacts.

Source Elimination and Control

The best way to address indoor air pollution is through aggressive source elimination and control.  Pollution should be prevented or reduced at the source whenever feasible.

  • Building materials:  If you are having the home constructed or remodeling your home select materials that do not emit volatile organic compounds.
  • HVAC System: Make sure your HVAC system distributes the minimum level of outdoor air throughout the home using whole-house mechanical ventilation.
  • Sealing Air Ducts:  Sealing ducts can help improve indoor air quality by reducing the risk of pollutants entering ducts and circulating through your home as well as preventing the loss of conditioned air.
  • Air Duct Cleaning: Ventilation systems distribute the air you breathe. Have the air ducts and HVAC system professionally cleaned to remove construction debris and pollutants.
  • Monitor use of household cleaning supplies:  Some household chemicals can be extremely dangerous.  Choose environmentally safe cleaning supplies, and make sure that the area is well ventilated.
  • Check exhaust systems:  Make sure exhaust fans are clean and unobstructed. Exhaust systems are responsible for removing moisture, odors, fumes, and carbon monoxide.

Top 10 Ways Homeowners Can Ensure Good Indoor Air Quality

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Ensuring good indoor air quality is easy once you have an understanding of the components that effect your homes environment.  Using the steps below, perform a quick checklist to improve your indoor quality.

Setting the Standard for Indoor Air Quality

ASHRAE, the American Society of Heating, Refrigeration and Air Conditioning Engineers developed Standard 62.2, Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings.  The standard, which is widely accepted by green builders, state and local around the counties, defines the roles of and minimum requirements for mechanical and natural ventilation systems and the building envelope in order to provide acceptable IAQ in low-rise residential buildings.

10 Steps to Ensure Good Indoor Air Quality

  1. Vent bathrooms, kitchens, toilets and laundry rooms directly outdoors.  Use energy efficient and quiet fans.
  2. Avoid locating furnaces, air conditioners and ductwork in garages or other spaces where they can inadvertently draw contaminants into the house.
  3. Properly vent fireplaces, wood stoves, and other hearth products; use tight doors and outdoor air intakes when possible.
  4. Vent cloths dryers and central vacuum cleaners directly outdoors.
  5. Store toxic or volatile compounds such as paints, solvents, cleaners, and pesticides out of the occupiable space.
  6. Minimize or avoid unvented combustion sources such as candles, cigarettes, indoor barbecues, decorative combustion appliances or vent free heaters.
  7. Provide operable windows to accommodate unusual sources or high-polluting events, such as the use of home cleaning products, hobby activities, etc.
  8. Use sealed-combustion, power-vented or condensing water heaters and furnaces.  When natural-draft applications must be used, they should be tested for proper venting and should be located outside the occupied space when possible.
  9. Put a good particle filter or air cleaner in your air handling system to keep dirt out of the air and off your ductwork and heating and cooling components.
  10. Distribute a minimum level of outdoor air throughout the home using whole-house mechanical ventilation.

Source: ASHRAE Standard 62.2 Ventilation and Acceptable Indoor Air Quality on Low-Rise Residential Buildings, and 2001 ASHRAE Handbook, Fundamentals, Chapter 26, Ventilation and Infiltration.

Fiberglass Air Duct Liners | A Serious Indoor Air Quality Concern

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Most commercial air duct systems are internally lined with fiberglass duct liners.  Deteriorating fiberglass duct liner is a very common cause for indoor air quality complaints and adverse health effects.

Fiberglass Duct Liner

Fiberglass internal duct liner is commonly used in many commercial heating, ventilation, and air conditioning (HVAC) system.  Fiberglass duct liner provides sound attenuation by dampening noise from HVAC equipment, and sound from adjacent office spaces.  Fiberglass duct liner provides thermal insulation for air ducts, preventing the air ducts from losing expensive conditioned air.

Fiberglass Duct Liner Deterioration

Over time internal fiberglass duct liner is exposed to varying degrees of air turbulence, temperature and humidity.  These environmental changes take its toll on the duct liner, breaking down its primary seal.

The primary seal is a black gritty coating on the surface of the duct liner which locks down the fiberglass fibers.  Deteriorated primary coating migrates through the ventilation system depositing within HVAC components and eventually entering the indoor air.

After the primary seal has fully deteriorated, it allows raw fiberglass fibers to be exposed to the airstream.  Turbulent airstreams wick the raw fiberglass fibers through the ventilation system, creating additional deposits within HVAC components and exposing building occupants to raw fiberglass fibers.

Health Effects of Fiber Glass Fibers

Health effects from exposure to fiberglass can be different depending on the fiber size and type of exposure.  Fiberglass, at a minimum, is an acute physical irritant to the skin, eyes, and upper respiratory tract.

  • While no long-term health effects should occur from touching fiberglass. Rashes can appear when the fibers become embedded in the outer layer of the skin.
  • Eyes may become red and irritated after exposure to fiberglass as occupants touch horizontal surfaces with deposits of fiberglass fibers, and rub their eyes.
  • Soreness in the nose and throat can result when fibers are inhaled. Asthma and bronchitis can be aggravated by exposure to fiberglass.
  • Temporary stomach irritation may occur if fibers are swallowed.

How Can Fiberglass Air Ducts Be Repaired?

If caught in the early stages of deterioration the internal fiberglass duct liner can be repaired.  Fiberglass duct liner can be resurfaced with an encapsulate specifically designed for HVAC systems.   Initially a commercial air duct cleaning needs to be performed to remove the foreign debris from the air duct surface to ensure for a proper bond.  After the air duct system is cleaned, the encapsulate is applied to the air duct surface locking down the fiberglass fibers.

If the internal fiberglass lining to too deteriorated, the lining must be removed and replaced.  If the damage is localized,  new internal internal insulation can be installed within the ducting.  If the damage is extensive, consider removing the damaged insulation and wrapping the air ducts with an external fiberglass insulation.

The Danger of Dust Mites

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Dust is a combination of pollen, plant and mold spores, pet dander, human skin, lint, bacteria, and other contaminants. While any of these can affect breathing and allergies, dust mites can be a particular problem.

What is a Dust Mite?

Dust mites are tiny insects that are invisible to the naked eye that feed on human skin flakes.  Dust mites thrive in stable environments like indoor dwellings and can survive in almost any temperature at almost any altitude. In other words, dust mites are in every home that has dust.

Why are Dust Mites Dangerous?

Dust mites can negatively affect human health because they are a common trigger for allergies and asthma.  Body parts and feces from dust mites can trigger asthma in individuals with allergic reactions to dust mites, and exposure to dust mites can cause asthma in children who have not previously exhibited asthma symptoms.

How to Control Dust Mites

While you cannot eliminate dust mites, the easiest way to limit the amount of dust mites in your home is to limit the amount of dust in your home.

  • Wash bedding and pillows in frequently as dust mites thrive in these areas where skin flakes collect.  If necessary, mattresses and pillows can be covered in allergen-impermeable covers.
  • Avoid furry and feathered pets as they contribute to the food sources for dust mites.  If you cannot part with your pet, prevent them from occupying your sleeping area.
  • Vacuum fabric furniture and carpet with vacuum cleaner equipped with a high efficient vacuum filter.
  • If you have children, choose washable stuffed toys, and keep stuffed toys off the bed.
  • Dust all surfaces weekly.  Do not scatter dust, use a damp cloth when dusting.
  • Maintain a low relative humidity; the ideal relative humidity in a home is between 30-50%.
  • Have the air ducts cleaned.  Ventilation systems require routine maintenance to prevent dust from being re-circulated throughout the home.
  • In rare instances, chemicals may be recommended to eradicate dust mites, if this is necessary speak to a professional.

Pigeons Cause Devastating Indoor Air Quality and HVAC Problems

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Pigeon problems have devastating effects on the heating and cooling components and indoor air quality of a commercial facility.  Pigeon problems affect employees, maintenance personnel and potentially customers.

HVAC Systems Make Perfect Pigeon Coups

Unfortunately, rooftop heating and cooling units are a perfect place for pigeons to nest.  To seek shelter from the elements, pigeons typically enter air handler units through the fresh air intakes and build their nests within the HVAC unit.  A single pair of pigeons can generate up to 18 new pigeons per year.  Once a nest is established, pigeons are extremely territorial.

Indoor Air Quality

An HVAC system distributes the air throughout a facility.  The bacteria, fungi and parasites that live and grow in pigeon droppings can carry and transmit any of 60 known diseases.  Exposure to pigeon feces and other organic matter such as feathers carcasses and nesting material from the HVAC system may pose a considerable health threat to people who come in contact with them or inhale the airborne particles from them.  Every precaution should be taken to ensure that building occupants and maintenance personnel are protected from pigeon feces.

Damage to HVAC Systems

As pigeons live in the air handler units they peck through filter material allowing unfiltered air and pigeon contaminants to freely enter the ventilation system.  There are numerous damaging effects to an HVAC system.

  • Filter banks: Pigeons peck though filter banks allowing for unfiltered air and pigeon contaminants to be drawn into HVAC components and supply air ducts.
  • Fan Blower: Pigeon debris builds within the fan blades decreasing airflow.
  • Air conditioner coils: Pigeon debris compacts within air conditioner coils and clogs the drain pan.
  • Insulation: Pigeons peck at insulation to create nesting material allowing for raw fiberglass fibers to enter the airstream.

How Do You Correct Pigeon Problems?

 

Hire a professional wildlife service or animal control contractor to relocate existing pigeons, and install devices to prevent future intrusions.  Have the pigeon debris removed by a professional air duct cleaning contractor.  Be sure to have the air duct cleaning contractor inspect the supply air ducts downstream of the HVAC unit.

The Quality of Your Indoor Air

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Evidence has shown that the air within homes and other buildings can be more seriously polluted than the outdoor air.  Several factors contribute to poor indoor air quality that can be easily controlled.  Follow these simple tips improve your indoor air.

Identify and Remove Pollutant Sources

The relative importance of any single source depends on how much of a given pollutant it emits and how hazardous those emissions are.  Educate yourself on the different types of biological, gas, or particulate pollutants that can potentially affect your indoor air quality and takes steps to remove them.  To have a greater understanding of potential indoor pollutants read “Understanding Indoor Air Pollutants“.

Improve Air Ventilation

If too little outdoor air enters a home, pollutants can accumulate to levels that can pose health and comfort problems.  Most home heating and cooling systems, including forced air heating systems, do not mechanically bring fresh air into the house.  When weather permits open windows to increase ventilation.  If you are intending to filter the outside air consider improving your heating and cooling system by having it modified to draw filtered outside air

Improve Filtration

There are many types and sizes of air filters and air cleaners on the market.   As air is circulated through a forced air ventilation system debris is trapped within the furnace filter. Use furnace filters with a MERV rating between 7 to 11, and change the filter every 2 months that the filter is in use.  If a standalone filtration device is used, use a device that has a high-circulation rate and highly efficient filter.

Smoke and Fire Damaged Air Ducts

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An air duct system is very efficient at spreading smoke.  When a fire occurs, the entire HVAC system will be contaminated, to a lesser or greater degree.  It is likely that the air duct system will distribute smoke damage well beyond the area of the fire.

Smoke Damage from an Active Air Duct System

Unfortunately, a forced air ventilation system is rather effective at spreading smoke damage.  Smoke is drawn into return air vents, through the furnace components, and distributed throughout the home or building through the supply air ducts.  If the HVAC system was operating at the time of fire, the return air side will be the most contaminated.

Passive Air Duct Smoke Damage

Even if the heating and ventilation system is not in use, there is a natural or passive air movement throughout the ventilation system.  If the air duct system wan not in operation during the fire, the return and supply air ducts closest to the fire will be the most contaminated.

Absorption of Odors

Smoke is naturally attracted to metal surfaces and is corrosive in nature.  As the smoke enters the air ducts it will cling to the steel, and will absorb into the debris within the air duct system.  A ventilation system has to be thoroughly cleaned in order to remove smoke damage.

Odor Oxidizer

After the ventilation system has been cleaned, an odor oxidizer is applied within the air ducts.  An odor oxidizer naturally breaks downs the odor causing chemicals of the smoke damage.

Encapsulation

In some instances of extreme smoke damage, air ducts will need to be encapsulated to remediate the smoke damage.  After the air ducts are cleaned, an encapsulates approved for use within HVAC systems is applied uniformly throughout the ventilation system.

Green Air Duct Cleaning


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Green air duct cleaners employ advanced methods and materials specifically for green cleaning.   They make an extra effort to not allow any dust to escape outdoors or indoors, and only use natural cleaning products.

Clean & Maintained Air Duct Cleaning Equipment

Green air duct cleaning companies ensure that equipment is cleaned and maintained to prevent introducing contaminants into the home or business.  HEPA vacuums require routine inspection to ensure that the filter is properly sealed and operating at peak performance.  HEPA filtered vacuums to prevent dust from being re-released into the air.

No Dust Escapes

No dust should enter your home or be released outside during the air duct cleaning process. Green air duct cleaning companies use source removal cleaning procedures to mechanically agitate and HEPA vacuum debris from the wall of the air ducts.

Green Cleaning Products

Cleaning solvents are needed to clean debris air vent vent registers and furnace components.  Only non-toxic, biodegradable, non-corrosive, non-flammable, environmentally safe cleaning products are to be used.

Limited Use of Sanitizers

Sanitizing agents should  ONLY be used if there is microbial problem. Any sanitizer used in the HVAC system must be specifically registered by the EPA or other applicable regulatory agency for the use in HVAC systems.

Never Use Scented Sprays

Green air duct cleaning companies never use scented spays within air ducts.  A proper cleaning of the air vents will remove the debris harboring the odor.  Scented sprays mask odors, and can potentially cause an adverse reaction to home or building occupants.

How Indoor Air Quality Affects People

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The greatest difficulty in solving indoor air quality problems is that effects on people can vary.  One of a pollutant can have a completely different effect on two different people.  While pollutants found in indoor air can be responsible for many harmful effects, there is considerable uncertainty as to what concentrations or periods of exposure are necessary cause specific health problems.

Immunocompromised Individuals

People who are immunocompromised have an immune system that is compromised or entirely absent.  Indoor air quality is of great concern to those who are immunuocomprimised, as their bodies are very vulnerable to opportunistic infections.

Hypersensitivity

Some people can become sensitized to biological & chemical pollutants after repeated or high level exposures. Effects may show up after a single exposure or repeated exposures.  Once sensitized to a pollutant, the individual can experience acute adverse reactions when they are exposed to that pollutant, even when the pollutant is at a lower level.

Age Makes a Difference

Children are sensitive to indoor air quality because they breathe faster than adults, inhaling up to 50% more air per pound of body weight than adults.  Elderly have a higher risk for cardiovascular, respiratory illness from fine particle pollutions.

Allergies & Asthma

Dust is a mixture of many substances. Its content may vary from home to home, but the most common allergy triggers such as mold spores, pollen, dust mites, can trigger allergy or asthma attacks.

Fortunately for most healthy people, the symptoms of air pollution exposure usually go away as soon as the air quality improves.  Good housekeeping and good maintenance of the heating and air conditioning equipment is the most important methods for controlling exposure to indoor air pollutants.

Understanding Indoor Air Pollutants

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A host of different biological, gas, and particulate pollutants can affect the indoor air quality.  The types of contaminants and the amounts that are suspended in the air determine air quality.

Biological Air Pollutants

Biological pollutants are or were living organisms. While all of us are exposed to biological pollutants in one form or another, the effects on our health depend upon the type and amount of biological pollution and the individual person.  Two conditions are essential to support biological growth – nutrients and moisture.  Keeping an area clean and dry is the best method to prevent biological air pollutants.

Common biological air pollutants:

  • Pet Hair & Pet Dander
  • Mold
  • Dust Mites
  • Pollen
  • Cockroach parts

Chemical & Gas Air Pollutants

Chemical and gas pollutants are the most hazardous of all air pollutants as they are often odorless, tasteless and invisible.  Ensuring proper exhaust, using building products with low levels of volatile organic compounds, and prohibiting smoking indoors are the best methods for preventing chemical and gas air pollutants.

Common chemical & gas pollutants:

  • Carbon Monoxide
  • Radon
  • Smoke
  • Building Materials with volatile organic compounds

Particulate Air Pollutants

Particulate air pollutants are particulates that have the ability to become air born when disrupted. The size of particles is directly linked to their potential for causing health problems. Particles that are 10 micrometers in diameter or smaller are of greatest concern because they can pass through the throat and nose and enter the lungs.  Good house keeping and construction containment practices are the best methods for lowering particulate air pollutants.

Common particulate air pollutants:

  • Drywall
  • Fiberglass
  • Concrete
  • Carpet fibers
  • Sawdust