Typical responses to allergens may include skin irritation, mucous production, muscle spasms, hives, rashes, membrane and tissue swelling, and a variety of other symptoms. Symptoms generally are short-lived in early physiological responses, but in repeated exposure to the allergen responses by the body may become increasingly severe and may require medical attention.

Exposure typically comes from within the environment where a person spends the majority of their time. Pollution and ambient outdoor air quality, in conjunction with the cleanliness of the indoor environment, play important roles. All of these components must be factored in during an IAQ investigation.

Allergies are relatively common in today’s society. Allergens causing reactions can enter the body through inhalation, injection, absorption and ingestion. The exposure each individual receives is unique. It is dependent not only on what they are exposed to in the environment at home, but also the workplace, the public areas that person inhabits, and the places a person visits outside their daily routine. This aspect may complicate an indoor air quality investigation when source allergens are trying to be isolated.

These facts require environmental, safety and health professionals and companies that have involvement in the indoor air quality industry, to exercise prudence and care when inspecting, assessing and cleaning of buildings or systems supplying air to areas where asthmatics or other allergy sufferers are present. It’s also an important component (pre-dispositions for respiratory distress) in identifying the appropriate allergen in an IAQ investigation.

The Environmental Protection Agency in their guidance document “Building Air Quality, A Guide for Building Owners and Facility Managers” recommends that contaminant-producing activities be scheduled for during unoccupied periods and the susceptible individuals be notified of upcoming events so theme avoid contact with any allergens being cleaned, and which could potentially remain in the building. Relocation of these individuals is recommended by the EPA only as a last resort.

In order to properly clean a heating, ventilation and air-conditioning system in an immuno-compromised (allergic or asthmatic) individual’s home or workplace, strict attention-to-detail is required during indoor air quality projects. HVAC system cleaning recommendations include cleaning systems that are placed under negative air pressure with appropriate high efficiency particulate air (HEPA) filtration units during cleaning operations. This is done to control present or future impacts to allergic or asthmatic individuals.

The use of these units has benefit in several areas. It serves as a measure to prevent unwanted migration of contaminants out of the system and will also purge the air in the system of particulate levels. In practicing these minimal engineering controls, the goal is to eliminate or reduce any potential for material inside the HVACs stem that was dislodged during the cleaning process to beamed airborne once the system is restarted.

The NADCA ACR Standard requires surfaces within the HVAC system to be visibly clean—free from non-adhered substances and debris. In instances where the highest level of cleaning is required, the NADCA Vacuum Test can be applied. To be considered clean by the NADCA Vacuum Test, the net weight of debris collected on the filter media should not exceed 0.75mg/100cm2.