Pollen and Mold Report

Pollen and Mold Report


A pollen and mold report is a report of the amount of airborne allergens currently found in the air at a specific location. This information is useful to anyone who is diagnosing, treating or managing an allergic disease. The report includes counts for four separate types of allergens:

  • Tree pollen
  • Grass pollen
  • Weed pollen
  • Mold spores

Levels in the report are expressed as absent, low, medium, high and very high. Low levels indicate that very few individuals with allergies should experience symptoms, while high levels indicate that most allergic individuals will likely experience symptoms.

These types of reports are most useful to those individuals suffering from airborne allergies (e.g., hay fever, allergic conjunctivitis) and asthma. The information can be used to inform allergic or asthmatic individuals about times they may want to avoid going outside. It can also be used to indicate when to take certain types of preventative allergy treatments (e.g., antihistamines).

Pollen and mold reports are compiled through networks of individual counting stations, which each use air sampling devices to test the air in their own area. Usually a single counting station is adequate to report the pollen and mold conditions for an entire city or community.

One of the most accurate and well known reporting networks is the National Allergy Bureau’s pollen and mold report (known as the Aeroallergen Network). This report is provided through the American Academy of Allergy, Asthma and Immunology (AAAAI), and can be accessed by calling 800-9-POLLEN or on the Internet at http://www.aaaai.org/nab.

Pollen forecasts may also be available. A network of counting stations use data on atmospheric conditions and seasonal changes to predict the severity of pollen counts. The report specifies the type of pollen that is most prevalent and is specific to individual geographic regions throughout the United States and Canada.

About pollen and mold reports

Pollen and mold reports are used for the diagnosis, treatment and management of allergic diseases. They are able to determine the amount of tree pollen, grass pollen, weed pollen and mold spores currently in the air at a specific location. These levels are indicated by a number representing the number of particles (pollen grains or mold spores) per cubic meter of air in a 24-hour period.

Pollen and mold counts are determined through an extensive network of counting stations that use air sampling equipment to collect airborne pollen particles and mold spores. These sampling devices usually use a sticky, transparent surface to capture individual pollen and mold spores floating throughout the air. Once particles have been captured over a 24-hour period, the sample is examined under a microscope where the individual grains or spores can be counted. Samples are generally collected three times a week.

Pollen and mold spores are small enough that they are typically distributed throughout a large area by air currents. For this reason, a single counting station is usually adequate to determine the pollen and mold counts for a wide area – often a whole city or community. However, pollen counts can still vary significantly over even a small area due to local factors.

The mold report is based on exposure to outside air and should not be applied to indoor conditions. Indoor molds often represent a completely different set of spore types.

The Aeroallergen Network is one of the most accurate and well-known reporting systems, and is used by the National Allergy Bureau (part of the American Academy of Allergy, Asthma and Immunology [AAAAI]). This network uses approximately 85 different counting stations located throughout the United States as well as three in Canada.

The Aeroallergen Network’s counting stations are staffed by AAAAI member volunteers. These volunteers are required to take a certification test and demonstrate their ability to calculate pollen or mold counts correctly.

The National Allergy Bureau’s pollen and mold report can be accessed by calling 800-9-POLLEN, or on the Internet at: http://www.aaaai.org/nab.

Oftentimes two different sources will report conflicting pollen or mold counts. There are several reasons why this may occur:

  • Human error. Because each individual counting station relies on humans to view and interpret data, errors can occur in reported pollen and mold counts. These errors are common, though usually very slight.
  • Sampling locations. Sampling devices used by the different counting stations can report slightly skewed results based on their specific location. A sampling device located under a single pollinating tree, for instance, is likely to show a higher pollen count than is actually represented by the rest of the surrounding area.
  • Different types of particles. Some pollen and mold reports refer to the total number of pollen particles or mold spores in the air. Other reports only take into account the number of allergenic pollen particles or mold spores in the air, and do not include particles that are not usually associated with allergies (e.g., pine tree pollen).
  • Type of sampling device. There are several different types of sampling devices available for determining pollen and mold counts. Using two different types of device may return different results even if used in the same area (see Types of sampling equipment).
  • Pollen booms. Some trees and plants pollinate in sudden booms, sending pollen counts soaring for several days. These elevated levels of pollen can overwhelm some types of air sampling devices, leading to inexact pollen counts.

In addition, samples taken at different times of day can cause a disparity between two counting stations in the same city. For instance, pollen concentrations are typically highest in the morning. Therefore, a pollen sample taken later in the day may be considerably lower. A change in temperature, wind conditions, humidity or precipitation can also affect allergen levels.

Types of sampling equipment

Typically a counting station, which gathers data on the amount of pollen and mold in the air, will use one of several types of devices to make its assessment. These devices include:

  • Sedimentation samplers. Commonly known as a Durham Sampler, this device catches pollen and mold particles on a microscopic slide coated with an adhesive.
  • Rotating-arm impactor samplers. These devices use plastic rods that are mechanically rotated to more efficiently collect particles onto the small collection surface.
  • Suction/cascade impactor samplers. These devices suck air through several stages. Each stage has a trap that is capable of stopping successively smaller particles. This device can be used to estimate the diameter of certain particles, which is useful for accurately determining their type.
  • Liquid impingers. These devices use a vacuum pump to collect airborne particles. Water-based collection liquids are used to trap the particles.
  • Filtration samplers. These devices use filters with specifically defined pores to trap particles of various sizes.

Allergies affected by pollen & mold reports

Pollen and mold reports are useful to allergy sufferers who wish to know what allergens are present in the air where they live. Reports that cite the specific types of allergens present in the air can allow allergic individuals to better avoid allergic reactions. For example, an individual who consistently has more severe allergy symptoms when weed pollen is present in the air will learn to avoid outside activities when this allergen is present.

Physicians can also use pollen and mold reports to link a patient’s symptoms with a potential trigger. When the appearance of symptoms correlates with high levels of a certain allergen, it suggests a connection between the two.

Many allergic individuals use pollen and mold reports to determine when medication should be taken. Because some types of allergy medications should be taken before there is contact with the allergen (e.g., antihistamines), pollen and mold reports can warn an individual to preventatively take a drug before venturing outside.

Individuals with the following conditions are likely to benefit from a pollen and mold report:

  • Allergic rhinitis(hay fever). This inflammation of the mucous membrane that lines the nose is caused by an allergic reaction to pollens, molds or other airborne substances.
  • Asthma. This condition in which the airways become blocked or narrowed can be exacerbated by the presence of pollens or molds in the air.
  • Allergic sinusitis. This inflammation of the sinus cavities in the face often leads to a runny nose, headache and teeth sensitivity. Pollen and molds are often responsible for the allergic reaction that causes this condition.
  • Allergic conjunctivitis. This inflammation of the tissue lining the inside of the eyelid is caused by an allergic reaction – often to pollens or molds.
  • Vernal conjunctivitis. A sight-threatening inflammation of the membrane covering the back of the eyelid (tarsal conjunctiva). Allergens, such as pollen and mold, that come into contact with the eye are believed to be at the root of this condition.

  • Allergic bronchitis. This inflammation of the lung’s airways (bronchial tubes) is caused by allergens such as pollen and mold.

Researchers and pharmaceutical companies also have an interest in pollen and mold reports. The information often allows them to watch for trends in the allergens that typically trigger allergies. Pharmaceutical companies can use the data provided by these reports to better tailor their drugs to those who suffer from allergies. Researchers can also use the information to learn about plant growth stages and reproduction.

Understanding pollen and mold reports

Pollen and mold counts are expressed in the grains of particle present per cubic meter of air over a 24-hour period. This type of report usually indicates whether it is referring to mold spores, tree pollen, grass pollen or weed pollen. The particles counts are given in five different levels:

  • Mold. The higher the mold number, the more severe symptoms may become. These refer to outside mold levels.
    • Absent – 0
    • Low – 1 to 6,499
    • Moderate – 6,500 to 12,999
    • High – 13,000 to 49,999
    • Very high – Greater than 50,000

  • Tree pollen. Tree pollen levels are generally very potent.
    • Absent – 0
    • Low – 1 to 14
    • Moderate – 15 to 89
    • High – 90 to 1499
    • Very High – Greater than 1500

  • Grass pollen. One of the most potent and common sources of pollen.
    • Absent – 0
    • Low – 1 to 4
    • Moderate – 5 to 19
    • High – 20 to 199
    • Very high – Greater than 200

  • Weed pollen. Extremely potent, a single ragweed plant is capable of releasing over one million pollen grains a day when in season.
    • Absent – 0
    • Low – 1 to 9
    • Moderate – 10 to 49
    • High – 50 to 499
    • Very high – Greater than 500

The following is a sample pollen and mold report:

Particle typeLevelTotal count
(in cubic meters)
Tree pollenLow10/m3
Weed pollenHigh376/m3
Grass pollenAbsent0/m3

It is important to note that the levels provided in a pollen and mold report are not an up-to-date representation of the conditions at the time of the report. Instead, the reported counts reflect an average for the sampling period. For instance, allergen counts reported on Wednesday morning are likely a reflection of the average count for a 24 hour period ending some time Wednesday morning.

Questions for your doctor

Preparing questions in advance can help patients to have more meaningful discussions with their physicians. Patients may wish to ask their doctors the following questions related to pollen and mold reports:

  1. Would I benefit from following pollen and mold reports?
  2. Where can I find the pollen and mold report for our area?
  3. How often should I check the report?
  4. How should I interpret pollen and mold reports?
  5. How accurate are pollen and mold reports? Can I trust the information?
  6. What steps should I take when allergen levels are high?
  7. Do I need to take any special steps for moderate levels?
  8. Why do I sometimes find conflicting reports?
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