IAQ Tools for Schools
IAQ Reference Guide
Section 6 - Solving IAQ Problems
- Developing Solutions
- Solutions for Other Complaints
- Evaluating Solutions
- Evaluating the Effectiveness of Your Solution
- Persistent Problems
If people are provided with information, they can act to reduce pollutant exposure.The selection of a solution is based on the data gathered during diagnostics (Section 5: "Diagnosing IAQ Problems"). The diagnostics may have determined that the problem was either a real or a perceived IAQ problem, or a combination of multiple problems. For each problem that is identified, develop a solution using the basic control strategies described below.
There are six basic control methods that can lower concentrations of indoor air pollutants. Often, only a slight shift in emphasis or action using these control methods is needed to control IAQ more effectively. Specific applications of these basic control strategies can be found in each team member’s checklist.
- Source Management — Managing pollutant sources, the most effective control strategy, includes:
- Source removal — Eliminating or not allowing pollutant sources to enter the school. Examples include not allowing buses to idle, especially not near outdoor air intakes, not placing garbage in rooms with HVAC equipment, and replacing moldy materials.
- Source reduction — Improving technology and/or materials to reduce emissions. Examples include replacing 2-stroke lawn and garden equipment with lower emitting options (e.g., manual or electrically powered or 4-stroke); switching to low emissions portable gasoline containers; and implementing technology upgrades to reduce emissions from school buses.
- Source substitution — Replacing pollutant sources. Examples include selecting less- or non-toxic art materials or interior paints.
- Source encapsulation — Placing a barrier around the source so that it releases fewer pollutants into the indoor air. Examples include covering
pressed wood cabinetry with sealed or laminated surfaces or using plastic sheeting when renovating to contain contaminants.
- Local Exhaust — Removing (exhausting fume hoods and local exhaust fans to the outside) point sources of indoor pollutants before they disperse.
Examples include exhaust systems for restrooms and kitchens, science labs, storage rooms, printing and duplicating rooms, and vocational/industrial areas (such as welding booths and firing kilns).
- Ventilation — Lowering pollutant concentrations by diluting polluted (indoor) air with cleaner (outdoor) air. Local building codes likely specify the quantity (and sometimes quality) of outdoor air that must be continuously
supplied in your school. (If not, see Section 2 of this Guide for ASHRAE recommendations.) Temporarily increasing ventilation as well as properly using the exhaust system while
painting or applying pesticides, for example, can be useful in diluting the concentration of noxious fumes in the air.
- Exposure Control — Adjusting the time and location of pollutant exposure. Location control involves moving the pollutant source away from occupants or even relocating susceptible occupants.
- Time of use — Avoid use of pollutant sources when the school is occupied. For example, strip and wax floors (with the ventilation system functioning) on Friday after school is dismissed. This allows the floor products to off-gas over the weekend, reducing the level of pollutants in the air when the school is reoccupied on Monday. Another example is to mow around the building and near play fields only before or after school hours.
- Amount of use — Use air-polluting sources as little as possible to minimize contamination of the indoor air.
- Location of use — Move polluting sources as far away as possible from occupants or relocating susceptible occupants.
- Air Cleaning — Filtering particles and gaseous contaminants as air passes through ventilation equipment. This type of system should be engineered on a case-by-case basis.
- Education — Teaching and training school occupants about IAQ issues. People in the school can reduce their exposure to many pollutants by understanding
basic information about their environment and knowing how to prevent, remove, or control pollutants.
Some solutions, such as major ventilation changes, may not be practical to implement due to lack of resources or the need for long periods of non-occupancy to ensure the safety of the students and staff. Use temporary measures to ensure good IAQ in the meantime. Other solutions, such as anti-idling programs, offer low-cost options that can be easily and quickly implemented.
Solutions for Other Complaints
Specific lighting deficiencies or localized sources of noise or vibration may be easily identified. Remedial action may be fairly straightforward, such as having more or fewer lights, making adjustments for glare, and relocating, replacing, or acoustically insulating a noise or vibration source.
In other cases, where problems may be more subtle or solutions more complex, such as psychogenic illnesses (originating in the mind), enlist the services of a qualified professional.
Remedial actions for lighting and noise problems can range from modifications of equipment or furnishings to renovation of the building. Reducing stress for school staff may involve new management practices, job redesign, or resolution of underlying labor-management problems.
To help ensure a successful solution, evaluate mitigation efforts at the planning stage by considering the following criteria:
- Operating principle;
- Installation and operating cost;
- Control capacity;
- Ability to institutionalize the solution; and
- Conformity with codes.
Mitigation efforts that create permanent solutions to indoor air problems are clearly superior to those that provide temporary solutions, unless the problems are also temporary. Opening windows or running air handlers on full outdoor air may be suitable mitigation strategies for a temporary problem, such as off-gassing of volatile compounds from new furnishings, but they are not acceptable permanent solutions because of increased costs for energy and maintenance. A permanent solution to microbiological contamination involves cleaning and disinfection as well as moisture control to prevent regrowth.
IAQ solutions that are durable are more attractive than approaches that require frequent maintenance or specialized skills. New items of equipment should be quiet, energy-efficient, and durable.
The operating principle of the IAQ solution needs to make sense and be suited to the problem. If a specific point source of contaminants is identified, treatment at the source by removal, sealing, or local exhaust is a more appropriate correction strategy than diluting the contaminant with increased ventilation. If the IAQ problem is caused by outdoor air containing contaminants, then increasing the outdoor air supply will only worsen the situation, unless the supply of outdoor air is cleaned.
Installation and Operating Costs
The approach with the lowest initial cost may not be the least expensive over the long run. Long-term economic considerations include energy costs for equipment operation, increased staff time for maintenance, differential cost of alternative materials and supplies, and higher hourly rates. Strong consideration should be given to purchasing ENERGY STAR qualified products.
It is important to select a solution that fits the size and scope of the problem. If odors from a special use area such as a kitchen entering nearby classrooms, increasing the ventilation rate in the classrooms may not be successful. If mechanical equipment is needed to correct the IAQ problem, it must be powerful enough to accomplish the task. For example, a local exhaust system should be strong enough and close enough to the source so that none of the contaminant moves into other portions of the building.
Ability to Institutionalize the Solution
A solution will be most successful if it is integrated into normal building operations. To ensure success, solutions should not require exotic equipment, unfamiliar concepts, or delicately maintained systems. If maintenance, housekeeping procedures, or supplies must change as part of the solution, it may be necessary to provide additional training, new inspection checklists, or modified purchasing guidelines. Operating and maintenance schedules for heating, cooling, and ventilation equipment may also need modification.
Conformity with Codes
Any modification to building components or mechanical systems should be designed and installed in conformance with applicable fire, electrical, and other building codes.
Evaluating the Effectiveness of Your Solution
Two kinds of indicators can be used to evaluate the success of correcting an indoor air problem:
- Reduced complaints.
- Measurement of the properties of the indoor air.
A solution will be most successful if it is integrated into normal building operations.Although reduction or elimination of complaints appears to be a clear indication of success, it may not necessarily be the case. Occupants who feel their concerns are being heard may temporarily stop reporting discomfort or health symptoms, even if the actual cause of their complaints has not been corrected. On the other hand, lingering complaints may continue after successful mitigation if people are upset over the handling of the problem. A smaller number of ongoing complaints may indicate that multiple IAQ problems exist and have not been resolved.
Measurements of airflows, ventilation rates, and air distribution patterns can be used to assess the results of control efforts. Airflow measurements taken during the building investigation can identify areas with poor ventilation; later they can be used to evaluate attempts to improve the ventilation rate, distribution, or direction of flow. Studying air distribution patterns will show whether a mitigation strategy has successfully prevented the transportation of a pollutant by airflow. While in some cases measuring pollutant levels can help determine whether IAQ has improved, in many cases this may be difficult and/or cost prohibitive. Concentrations of indoor air pollutants typically vary greatly over time, and the specific contaminant measured may not be causing the problem. Measuring a specific pollutant by a professional is appropriate if the problem can be limited to that pollutant. For further information on IAQ measurements, see Appendix B: "Basic Measurement Equipment."
Ongoing complaints may indicate that multiple IAQ problems have not been resolved.Sometimes even the best-planned investigations and mitigation actions will not resolve the problem. You may have carefully investigated the problem, identified one or more causes, and implemented a control system. Nonetheless, your efforts may not have noticeably reduced the concentration of the contaminant or improved ventilation rates or efficiency. Worse, the problem may continue to persist.
If your efforts to control a problem are unsuccessful, consider seeking outside assistance. The problem could be fairly complex, occur only intermittently, or extend beyond traditional fields of knowledge. It is possible that poor IAQ is not the actual cause of the complaints. Bringing in a new perspective at this point can be very effective. Appendix A: "Hiring Professional Assistance" provides guidance on hiring professional IAQ assistance.