Most people spend a majority of their time in different kinds of buildings. This makes the quality of air in these environments a crucial factor in human health and comfort.
Many building-related pollutants can contaminate indoor air. These include: construction-generated contaminants, radon, and volatile organic compounds. The use of proper construction management plans and good scheduling are essential to reduce migration of outdoor construction-generated pollutants into occupied spaces.
Ventilation
The ventilation rate in a house depends on building design, occupant activities and construction materials. Ideally, ventilation is designed to provide a constant flow of fresh outdoor air. This helps to reduce indoor pollutants by diluting them with outdoor air, preventing their accumulation.
Air pollutants can come from a variety of sources in any home, including deteriorated or damaged insulation, pressed wood products, paints and other finishes, tobacco smoke, cleaning, redecorating and hobbies; heating, cooking and ventilation appliances; people and pets. Some of these sources release pollutants more or less continuously, while others only release them intermittently. When ventilation systems are inadequate, pollutants can accumulate to levels that cause discomfort or health problems.
Rising energy prices have prompted many builders to lower the ventilation rates in new homes to save on heating and cooling costs. However, this can lead to a build-up of indoor air pollutants, and can make it difficult to achieve good IAQ.
Besides ventilation, air pollution can also be reduced by the use of low-emitting construction materials and smart designs that optimize indoor contaminant levels. Plants are an excellent choice, as they naturally remove harmful compounds from the air as part of their metabolic process.
Insulation
Many pollutants cause symptoms ranging from irritation of the eyes, nose and throat to respiratory disease, cognitive deficits and cancer. These pollutants are released from building materials, furnishings, activities like smoking, cleaning and redecorating, radon, and products such as pesticides, air fresheners and cleaning agents. Many of these releases occur more or less continuously, while others happen intermittently and may be exacerbated by unvented activities, or by poor indoor/outdoor air exchange.
Rigid foam boards like polystyrene and polyisocyanurate (polyiso) are used to insulate the walls, floors and ceilings of homes and commercial buildings. They are particularly effective for reducing thermal conduction in wall cavities and reduce energy costs by slowing heat loss through walls and other structural elements.
Other insulating materials include bulky fibers like fiberglass and rock wool, cellulose, natural or synthetic fibers, phenolic foams and cementitious foams; and sleek foils. All have lower thermal conductivity than most metals, and most have a low coefficient of expansion, which increases resistance to heat flow in living spaces.
Good construction management plans and careful sequencing of projects can prevent long-term impacts on indoor environmental quality. Isolating work areas and avoiding pathway interruptions helps to limit the absorption of volatile organic compounds (VOCs) by porous materials such as drywall. These controls also protect workers during construction and renovation, as well as building occupants for years to come.
Finishing
Many materials used to make buildings are manufactured using chemical processes, including flooring, drywall, paints and varnishes, and furniture. Most of these products off-gas a variety of harmful chemicals, such as formaldehyde and volatile organic compounds (VOCs).
These off-gasses are often a cause of poor indoor air quality and can trigger asthma symptoms in those who suffer from it. To prevent these problems, ask your building material providers for low-VOC options. In addition, select floor finishes that are free from harsh chemicals. Vermont Natural Coatings, for example, uses whey (a byproduct of cheesemaking) as the bonding agent in their PolyWhey product, which emits significantly fewer VOCs than conventional wood floor finish.
Finally, it’s important to schedule renovations such as roof work and refinishing on weekends or after hours when possible to reduce the impact on occupants. Additionally, use containment and isolation to separate construction areas from occupied spaces and inform all workers of indoor air quality concerns during the work process.
Research shows that people spend up to 90 percent of their time indoors, which is why it’s so important to maintain good indoor air quality (IAQ). Several studies examined IAQ in different buildings and compared them in terms of the amount of formaldehyde and carbon dioxide emitted from various sources such as traditional and new building materials, furnishings, cleaning agents, cooking systems, and household activities.
Furnishings
While indoor pollutants are most often associated with homes, offices can also suffer from inadequate ventilation. The European Respiratory Society lists common office pollutants as environmental tobacco smoke, asbestos from insulating and fire-retardant building supplies, formaldehyde from pressed wood products, other organics (building materials, cleaning products, restroom air fresheners), volatile organic compounds and biological contaminants.
The type of furniture you choose can have a significant impact on your indoor air quality. Many modern furniture pieces are upholstered in fabrics that can release VOCs into the air. These chemicals, when inhaled over long periods of time at high concentrations, can cause a variety of health problems including nose and throat irritation, nausea, loss of coordination and more serious conditions like cancer.
Furniture made of pressed wood may also release VOCs due to the glues and finishes used in manufacturing. Some of these contain chemicals like benzene and xylene that can be dangerous when inhaled for extended periods. It’s important to look for natural fiber furniture whenever possible so that you can avoid these harmful chemicals.
Other factors that affect indoor air quality include the outdoor climate and weather conditions, occupant behavior and activities, and ventilation systems. For example, some climatic conditions can increase the risk of mold growth and some diseases like Legionnaires’ disease or humidifier fever by encouraging microorganisms to grow in home heating and cooling systems or humidifiers.