Asthma is the most common chronic disease affecting more than 35 million people, including 6 million children. Each year, the prevalent disease causes more than 5 million emergency room visits and 500,000 hospitalizations.
According to EPA “Americans spend up to 90 percent of their time indoors. Indoor allergens and irritants play a significant role in triggering asthma attacks. Triggers are things that can cause asthma symptoms, an episode or attack or make asthma worse. If you have asthma, you may react to just one trigger or you may find that several things act as triggers. Be sure to work with a doctor to identify triggers and develop a treatment plan that includes ways to reduce exposures to your asthma triggers.”
Allergens or irritants such as mold, smoke, dust, dust mite, cat & cockroach allergen or pollen can cause the airways to become inflamed and narrow. If one parent has asthma, chances are one in three that each child will have asthma. If both parents have asthma, it is much more likely (7 in 10) that their children will have asthma. Symptoms may include wheezing, coughing, pain or tightness in the chest and shortness of breath. Not all asthma attacks are the same. In severe attacks, the airways can close so much that not enough oxygen gets to vital organs. This condition is a medical emergency.
The assessment of allergens in a house dust sample is an essential step for allergen-avoidance and provides information essential for allergen-reducing measures, in addition to managing the indoor environment from a health and hygiene point of view.
Some of the most common allergens in this category include but are not limited to:
• Dust mite (Der p 1, Der f 1P)
• Cockroach (Bla g 2)
• Cat (Fel d 1)
• Dog (Can f 1)
Exposure to these substances, even in small amounts, can trigger allergenic symptoms/disorders. Common symptoms of a house dust allergy include, but are not limited to, sneezing, itchy or watery eyes, nasal congestion and a runny nose. These signs appear as a result of production of immunoglobulin E (IgE) antibodies in a sensitive individual upon the exposure of dust allergens. In fact, IgE binds to mast cells in the mucosa in eye conjunctiva, nose, throat, and bronchi, and trigger a release of histamine. Histamine causes dilation of vessels in mucosa, and secretion
of mucus from mucous glands, resulting in mucosal swelling and mucus secretion, which gives allergenic symptoms.
Successful management of allergies due to house dust is a two-fold approach (i.e. clinical diagnosis of the allergy sufferer and environmental monitoring of the dwelling). The clinical evaluation of a patient includes symptom history, blood tests, IgE levels, evaluation of suspected allergens (skin prick or patch test), etc. whereas environmental monitoring reveals the identification and quantification of allergen load in house dust.
Culture (Bioaerosols) or non-culture (spore trap analysis) based methods and Polymerase Chain Reaction (PCR) are often used for enumerating allergens of the indoor environment. However, enzyme immunoassay (ELISA) of air or dust samples has been the gold standard for assessing indoor allergens. ELISA kits have been used for analyzing indoor allergens in house dust for years, although it is costly, time consuming and allergen specific.
Immunological assay for the determination of indoor allergens is available which evaluates five to eight most common allergens/sample in house dust. The immunological assay simultaneously measures House-Dust Allergens (HDA) such as mite allergens Der p 1, Der f 1 and Mite Group 2, animal allergens of cat (Fel d 1), dog (Can f 1), rat (Rat n 1) and mouse (Mus n 1) as well as cockroach (Bla g 2). Immunological assay provides improved performance (increased sensitivity, accuracy and precision) in a high throughput system with substantial time and cost savings. Concentration of identified allergens from indoor dust is reported as μg/gram.
Indoor environmental screening of the home or work environment is important for individuals with allergies, chronic sinusitis, rhinitis, emphysema, asthma, atopic dermatitis, immune deficiencies, etc. In keeping with the National Heart, Lung and Blood Institute (NHLBI) 1997 recommendations, it is desirable to identify and remove common allergens (e.g. molds) and modify the home or office to reduce the level of ubiquitous (common) allergens. Before one can remove allergens and/or pollutants effectively, it is essential to understand if they exist and in what quantity.
What are some types of indoor air pollutants that may affect my building or home?
• Biological contaminants: the biological contaminants can consist of bacteria, viruses, fungi (mold), dust mite allergen, animal dander, insect biodetritus, fibers and fiberglass, pollen, cockroach allergen, etc… and may result from inadequate maintenance and housekeeping, water spills, inadequate humidity control, condensation, or may be brought into the building by occupants, infiltration, or ventilation air. Allergic responses to indoor biological pollutant exposures cause symptoms in allergic individuals and also play a key role in triggering asthma episodes for an estimated 15 million Americans.
• Chemical pollutants: Volatile organic compounds (VOCs) are organic chemicals. VOCs are numerous, varied, and ubiquitous. They include both human-made and naturally occurring chemical compounds. Chemical pollutants can include tobacco smoke, emissions from products used in the building (e.g., office equipment; furniture, wall and floor coverings e.g. formaldehyde; and cleaning and consumer products) accidental spill of chemicals, and gases such as carbon monoxide and nitrogen dioxide, which are products of combustion.
• Particles. Particles are solid or liquid substances which are light enough to be suspended in the air, the largest (8 microns and greater) of which may be visible in sunbeams streaming into a room are typically non respirable. However, the smaller particles (7 microns and smaller) that you cannot see are likely to be more harmful to health since these are considered respirable. Particles of dust, dirt, or other substances may be drawn into the building from outside and can also be produced by activities that occur in buildings e.g. operation and maintenance practices, housekeeping practices, printing, copying, operating equipment, construction, remodeling, people….
Is establishing baseline IAQ conditions in my building important?
Yes, as Yogi Berra once said “if you do know where you are going, you might not get there?” Indoor air quality is no different. If you don’t know the present IAQ conditions of your building are and you are having IAQ upgrades performed to enhance your buildings IAQ then how would you know that you improved those conditions if you didn’t have a baseline to start with? You wouldn’t.
It is not practical to design a universal guideline fit for all in terms of exposure and health because immunity varies greatly from individual to individual. EDLab at Pure Air Control Services performed a 10 year study analyzing more than 7,000 buildings and over 25,000 environmental samples that were collected across the United States and abroad. The building type included both commercial and residential. The majority of samples analyzed were tested positive for bacteria and fungi.
In this study the average (normal baseline) concentration of air-borne culturable (viable) bacteria was 175 CFU (Colony Forming Unit)/m3, and the fungal concentration in ambient air was recorded at 350 CFU/m3. The average concentration of non viable air-borne mold/fungal elements was estimated at approximately 1,000 cts (counts)/ m3. These baseline numbers are used as a reliable indicator for an expected average disseminated microbial (bacteria/fungi only) concentrations in today’s modern buildings.
What to do next?
The Environmental Diagnostics Laboratory (EDLab) at Pure Air Control Services analyzes a wide array of environmental microorganisms (bacteria and fungi) including organisms such as Staphylococcus aureus and Legionella pneumophila. EDLab scientists identify microorganisms by using various lab techniques. Some common analysis performed by EDLab to identify microbial conditions include Bio-Scan and Spore Trap analysis, mycological culturable analysis of air/bulk/surface/swab/liquid environmental samples among many others. The type of sampling and analysis performed is determined by project specifications project requirements or individual needs.
For additional information you can contact Dr. Rajiv Sahay, Director, EDLab, Pure Air Control Services 1-800-422-7873 ext 303.
To discuss a more comprehensive environmental assessment of your building or home call the credentialed professional indoor environmental Building Sciences team at Pure Air Control Services 800-422-7873, ext. 802.