Month: June 2021

Indoor Air Toxins 101: Understanding Indoor Air Pollution

June 2, 2021

Indoor air pollution can come from many different sources. It’s important to understand how to control these risks.

The most common sources for air pollution in the home include the burning of combustible materials, which creates particulates, and gaseous emanations from building materials and products brought into the home for cleaning, grooming, and hobbies. Outdoor contaminants, including radon, pesticides, and outdoor air pollution, may also enter the home.

Most combustible materials release nitrogen dioxide (NO₂) and soot into the air. Heating systems, fireplaces, stoves, candles, and tobacco are all combustibles. NO₂ is an odorless and colorless gas that can irritate the eyes and nose and cause shortness of breath. Soot, which is floating particulates in the air, can be inhaled into the lungs, become lodged, and cause irritation and tissue damage. With sporadic exposure, trapped particulates can slowly be cleared. If, however, soot exposure is frequent, the particulates will not be effectively removed. The resulting irritation to the lungs’ airways can lead to infections and diseases such as bronchitis, emphysema, and lung cancer. Radon, if present in the home’s air, may attach to soot particulates and be inhaled into the lungs, where it can become stuck and potentially cause cancer.

Combustible materials also emit carbon monoxide, an odorless and colorless gas that is particularly dangerous. At lower concentrations, carbon monoxide can cause vague, flu-like symptoms, such as dizziness, headaches, nausea, and fatigue. At higher concentrations, however, carbon monoxide poisoning can cause death. When inhaled, carbon monoxide enters the lungs and passes into the bloodstream where it binds to hemoglobin in the red blood cells. Unlike oxygen and carbon dioxide, carbon monoxide forms a permanent bond with the hemoglobin molecule. The affected blood cell becomes permanently damaged and unable to deliver oxygen to the rest of the body. Carbon monoxide effectively causes suffocation. It is important to install carbon monoxide detectors on each floor of your home and to keep batteries properly charged.

See all the posts in this series on airborne toxins in your home:
Indoor Air Toxins 101: The Basics of Indoor Pollution
Indoor Air Toxins 101: Understanding How We Breathe
Indoor Air Toxins 101: Understanding Indoor Air Pollution
Indoor Air Toxins 101: The Dangers of Candles
Indoor Air Toxins 101: Reducing Indoor Black Soot
Indoor Air Toxins 101: VOCs, Asbestos and Lead
Indoor Air Toxins 101: Understanding Mold & Health

Indoor Air Toxins 101: Understanding How We Breathe

June 2, 2021

by Rob Brown

The quality of our indoor air is of paramount importance to our health.

We need to breathe air that has an adequate percentage of oxygen. In the atmosphere, air is composed of approximately 21% oxygen and 78% nitrogen. Carbon dioxide, water vapor, and other miscellaneous gases make up the remainder.

Indoor air is quite different, and the percentages of oxygen and other gases can vary dramatically, as many products in the home can emit gases and particulates that “pollute” the air. When we breath polluted air, some health effects can be felt immediately (acute) while others occur over the long term (chronic). The physical effects of air pollution may depend on the specific type of pollutant, its concentration, and an individual’s propensity for disease or underlying immune status. For instance, a similar dose of pollen or cat dander may not have any effect on one person, while for another, it may cause a hypersensitivity immune response.

Acute health effects from indoor air pollution can include irritation of the mucous membranes, particularly in the eyes, nose, and throat. Indoor air pollution can carry allergens, thereby increasing the occurrence of allergic reactions and asthmatic exacerbations. Headaches, dizziness, fatigue, and fever are some additional generalized symptoms that may develop following exposure to some indoor air pollutants.

Chronic exposure to indoor air pollutants is more insidious and includes various lung diseases, heart disease, and cancer.⁵ The exact concentration of a pollutant, such as benzene, and the duration of exposure needed to cause chronic disease are not clearly defined. A healthy immune system can help prevent the development of chronic disease, but a weak immune system may be ineffective at preventing the chronic adverse health effects from ongoing exposure to air pollution. With this in mind, for your own health and the health of others living in or visiting your home, it is best to reduce the concentration of your indoor air pollutants as much as possible.

Asthma is a chronic health condition in which the lungs’ airways become hypersensitive to chronic, repeated exposure of pollutants and other “triggers” that cause an allergic response. Triggers cause a transient narrowing or tightening down of the airways, reducing the flow of air into the lungs. If the airways are given a chance to relax for a prolonged period of time without irritation, the hypersensitivity response can lessen and even go away on its own.

Indoor Air Toxins 101: Understanding the Basics

June 2, 2021

by Rob Brown

Before we consider how indoor air toxins interact with our body, we want to be sure we understand the basics of how we breathe. Clean air is colorless, transparent, and intangible, yet it can contain all kinds of pollutants that make you sick. Some contaminants you can see with your eyes; others are invisible.

Air interacts with the body via two main mechanisms. You inhale air into your lungs during respiration (breathing) and you contact air with exposed surfaces of skin and mucous membranes. Breath is essential to life, but what exactly are we doing when we breathe? The body performs two functions with breath. One is to extract oxygen from the air because our cells utilize oxygen to produce energy and carry out their functions. The other is to release carbon dioxide, one of our body’s waste products. The aggregation of oxygen from the air and the release of carbon dioxide from the body occurs in the lungs.

When we inhale, muscles in the chest wall expand and a large flat muscle that separates the chest cavity from the abdominal cavity, called the diaphragm, contracts, creating negative pressure in the chest. This results in the movement of air through the nose or mouth, down the windpipe (trachea), and then into the lungs through passageways called bronchi and bronchioles. These passageways split and divide many times, normally becoming narrower as they reach farther and farther into the lungs. At the end of each passageway, there is a little balloon-type structure called an alveolus. Tiny blood vessels called capillaries pass through the walls of the alveolus, and as the blood within them enters, a protein in the blood cell called hemoglobin releases the carbon dioxide in exchange for oxygen. The blood cells then move back to the heart, which pumps them throughout the body, providing needed oxygen. This mechanism works because both oxygen and carbon dioxide form a reversible bond with hemoglobin.

When you exhale, the diaphragm and muscles of your chest relax and positive pressure is then exerted on your chest cavity. This causes air to flow backwards, out of the alveoli and through the bronchioles, bronchi, trachea, and finally out of your nose or mouth. This is the basic mechanism of respiration.

The body is well adapted—in most people—to clear out inhaled particulate debris. The cells that line the airways secrete mucous, which traps debris. Tiny hairs called cilia, which protrude from these cells, wave back and forth, moving the mucous and trapped debris up and out of the airway and into the back of the throat, where it is either swallowed or blown out of the nose during a sneeze. This mechanism helps keep the airways clean.

The other way in which we interact with air is via the skin, the largest organ of the body. Intact skin is lined by a layer of stratified squamous epithelium, which is the technical term to describe the layer of dead cells that forms a protective covering over the live cells. This layer of dead cells helps to prevent the underlying live skin cells from being harmed by the environment. Penetrating injuries, scrapes, and cuts cause a violation of this barrier and allow the environment to access the interior of the body. It has been shown that the outermost layers of skin absorb oxygen directly from the air. For this reason, it is sometimes preferable to leave skin injuries uncovered and exposed to the air.

All cells in the body, including skin cells and the cells that line mucous membranes, are surrounded by a protective envelope of fatty molecules called phospholipids, referred to as the cell membrane. Aerosolized solvents that dissolve into fat are able to penetrate cell membranes and enter cells directly.