The number of asthma attacks can be greatly reduced by eliminating as much as possible, known asthma triggers. Not all asthma triggers are easily controlled, but several can be. Those triggers that are closely related to allergy-triggered asthma are easier to control in a building than cold-weather or exercise induced asthma. Second hand smoke, pollen and mold spores, dust mites, cockroaches, and animal dander are major asthma triggers identified by the Environmental Protection Agency that can be controlled by taking a few steps.
Second Hand Smoke
No student or staff of OPS is exposed to second hand smoke in or around OPS property. OPS has maintained a strict “No Smoking” policy on district property, both buildings and grounds, since 1994. No smoking is allowed by staff, visitors or contractors throughout the year regardless of the presence of students in either the building or on school district property. No smoking is allowed in any OPS vehicle including those used for student transportation, delivery or maintenance.
Pollen and Mold Spores
Maintaining a regular schedule for changing filters is necessary to improve or maintain good indoor air quality. Pollen and mold spores are found in the outdoor air throughout most of the year. Filters are not able to remove all pollen or spores but will greatly reduce the number of each drawn into the building.
Infrequent air filter changing causes the filtering material to become overloaded, fall from its position and allow outdoor air to by-pass filtration and enter into the building unfiltered. Since most pollen and mold spores inside are drawn into the building via the ventilation system, a properly maintained filtration is important. Most pollen spores responsible for allergic reactions
Pollen and Mold Spores (continued)
are those from grasses, weeds and trees. Allergic responses to flowers are not common since flower pollen is usually heavy and waxy, not likely to become airborne.
Most mold spores detected indoors are drawn into the building through the outdoor air intake and escape capture in the filter media. By collecting and comparing data from air samples collected inside and outside the building, the possible source of the airborne mold spores can be determined. If the indoor air sample contains mold spores from a genus not identified in the outdoor sample, the mold colony producing the spores is presumed to be growing indoors. Likewise, an indoor concentration of a particular mold spore found at levels greater than concentrations detected outdoors indicates an amplification of mold spores (presumably from growth) generating from inside the building. Care must be taken when relying on this data alone to justify remediation projects.
Mold growth inside the building is usually the result of a water leak. Whenever water stains or leaks are observed they are to be reported immediately. Building engineer/custodial staff and maintenance work together to determine the potential source and initiate repairs. Water stains can indicate leaking pipes, leaking roofs, or dripping condensation from water lines. Many occupant activities can create incidental water pooling or concentrations sufficient enough to allow mold spores to germinate and grow. Lawn and garden sprinkler systems have also been found to contribute to this issue when water is sprayed against the building finding pathways through the building exterior if the moisture barrier is improperly placed or omitted in design.
Although most mold species require the presence of liquid water for a minimum of 48 hours, some species do not require liquid water to germinate. For example, certain species of Aspergillus require very little water and can grow in conditions that are too dry for other molds. Controlling relative humidity in buildings between 30 – 60% will help limit the opportunity for mold to germinate and grow.
Since mold spores are always present in the air (though greatly reduced in winter) wetted materials need to be dried within 48 hours. This timeline is critical to help prevent germination of mold spores. Water damaged soft surface materials, such as paper, stuffed animals, upholstered furniture and carpet, may not be salvageable even if it is dried within the 48 hour time. Any soft materials that have been wet for 48 hours or greater should be discarded. (Refer to Appendix A).
Potted plants can contribute to mold spore concentrations indoors although the overall amount is generally negligible. Potted plant soil should be inspected for signs of mold growth when watering. Also, plant surfaces can harbor molds that are visible as rust or sore spots on the host. However, these molds are generally pathogenic only the to plant and not to humans. Since Omaha is located in a predominately agricultural based ecosystem, a low concentration of plant pathogens spores in air samples is not uncommon.
Dust Mites
Proteins generated by dust mite fecal material and body fragments are the cause of dust mite allergies. These protein pieces are components of general house dust becoming airborne when
Dust Mites (continued)
disturbed, inhaled and can cause an allergic reaction of the mucous membranes or respiratory system in sensitive individuals.
An increase in the dust mite population in occupied buildings is often associated with increased humidity. One study suggests that dust mite populations are close to eliminated when the relative humidity is 60% or lower. Dust mites do not drink liquid water, but absorb water from the air and food particles. Dust mites thrive in environments that are warm (75-80 degrees Fahrenheit), humid (70-80% r.h.) and close to a source of food such as shed human skin cells, pollens, mold spores, bacteria and animal dander.
Since one human can shed approximately 1/5 of an ounce of skin cells each week any fibrous surfaces in areas where people congregate needs regular cleaning to control the population of this asthma trigger. Regular vacuuming and dusting will help limit the availability of skin cells, keep the dust mite population in check. Particular attention is needed when cleaning such surfaces as carpet, upholstered furniture, and bed linens. There has not been any proof that dust mites actually live in ventilation duct work. In extreme cases the proteins of the dust mite may be in sufficient concentration to become collected in the duct work.
Cockroaches
Just like dust mites, the proteins from excrement and released from the degradation of cockroach body parts can elicit an allergic response or an asthmatic reaction in some individuals. Cockroach population control depends on a number of factors including limiting the availability of water, food and shelter. Cockroaches do not require a lot of water but may come into a building in search of it. They are frequently found in areas where water is found such as bathrooms, kitchens, pipe chases, pipe tunnels, etc. Water condenses wherever moist humid air comes in contact with a cooler surface. Condensate on pipes or from an air conditioner is sufficient to support a cockroach. Some species of cockroach get enough water from food that they can survive for long periods of time without liquid water. Potted plants can also supply water to cockroaches. A layer of pebbles on the surface of the soil can help prevent this from happening.
Food is also critical for cockroach survival. Even small food crumbs can be a feast for these bugs. All food, including that found in classrooms, should be sealed in air tight containers to prevent access to the contents. Cockroaches are also fond of grease and can obtain enough food from grease spots to be sustaining. However, cockroaches are most attracted to protein as a food source. Nail clippings, hair, fur, skin cells from humans, animals, other insects or their parts are invitations for cockroaches. Again, frequent cleaning is important to remove their food source and help control these pests.
Cockroaches like to live in small spaces so that their back and legs are in contact with a solid surface. Tight spaces such as those found in cardboard, hollow legs and hollow cabinet doors are perfect shelter for roaches. Boxes stored in closets, basements or crawlspaces, not only create a
fire issue but provides a perfect habitat for cockroaches. Cockroaches generally live within 15 to
25 feet of their nest. Individual roaches may stray farther than that in search of food or water. If none is found, it will simply move on.
Cockroaches (continues)
Since cockroaches hunt for food so close to their nest, roach sightings including location need to be noted. Repeated sightings of young cockroaches are a good indicator of a nearby nest. Young cockroaches don’t stray as far from the nest as an adult does and will usually limit it’s exploration to a range of 5 to 15 feet.
Cockroaches are also thought to be attracted to electro-magnetic fields (EMF) such as those generated by electrical equipment. Care should be taken to check all potential sources of EMF in sighting areas during a pest inspection. Particulars concerning pest control can be found in the OPS Integrated Pest Management Plan. Contact OPS Environmental for more details.
Animal Dander
Total elimination of animal dander is virtually impossible as any occupant or visitor to the building can carry animal dander from their home on their clothing. This unlikely introduction of animal dander has been thought to be significant enough to cause allergic reactions in sensitive individuals.
Housing animals in classrooms is not encouraged but is not against district policy. Before pets are allowed in a classroom, each student or staff member should be questioned concerning their known allergies or asthma triggers. Classroom pets should be kept in cages and in spaces away from air flow. Under no circumstances are pet cages be placed on wall units that supply air to the room. Make a note of the air flow in the room and keep animal cages out of the supply and return air streams. Animal dander can be introduced to areas well beyond that classroom.
Regular cleaning of pet cages is a necessary part of controlling insect pests. Cleaning should be performed only by those persons with no sensitivities to animal dander and during unoccupied hours. Areas around the cage and where the cage was cleaned need to be cleaned also. Food for classroom pets needs to be kept in tough air tight containers such as jars with screw lids or heavy plastic containers with air tight fitted lids to prevent access by insects including cockroaches. Even fish food that is very high in protein content can attract different insects.
Diesel Exhaust
In the past few years the apparent effects of exposure to diesel fumes in relation to the onset of asthma has become an issue. Researchers speculate the fine particulate generated from diesel generated vehicles may reach the smallest recesses of the lungs and trigger asthma attacks or other respiratory problems.
OPS is currently in the process of installing diesel oxidation catalytic converters (DOC) on all student busses transported by the district. This project is scheduled to be completed during the summer of 2006, at least one year ahead of schedule. In addition, the district now purchases biodiesel fuel which is expected to further cut the emissions rate.
OPS drivers are trained annually and expected to comply with the district’s no-idling policy. Bus drivers are not allowed to “warm-up” diesel busses for more than five minutes and must shut off the engine when waiting for students before and after school.