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Everything To Know About Pollen Count

More than 50 million people in the United States live with nasal allergies. Half of those have seasonal pollen sensitivities [1], according to the Asthma and Allergy Foundation of America (AAFA). When the pollen count gets high, it increases the likelihood allergy sufferers will experience their worst symptoms.

If you are newly diagnosed with pollen allergies, you may be asking the following questions:

  • What is considered a high pollen count?
  • What is considered a low pollen count?
  • What is considered a standard pollen count?

Even if you have lived with pollen allergies for years, knowing how to monitor the pollen count can mean the difference between having a sneezy, wheezy, eye-watering day and being symptom-free.

There are several types of airborne pollen that can trigger mild, moderate, and severe symptoms in people with pollen allergies. Grass, trees, and weeds are among the largest producers of pollen.

Pollen-producing activity levels can vary and tend to ebb and flow by season. Most pollen-producing plants peak in the spring and summer months [2], according to the American College of Allergy, Asthma, and Immunology (ACAAI). There are some — ragweed, mold — that make their grand appearance in the fall.

Most pollen is a fine, yellowish powder that spreads quickly via animals, insects, and the wind. Pollen’s main purpose is to fertilize plants, but it is not picky about where it lands.

You may find it on your vehicles, outdoor furniture, and even on the outside of your windows. If it is a particularly heavy pollen day, it can even get stuck in your hair and clothing, which helps it travel indoors everywhere you go.

Living in a bubble is not a good solution to preventing pollen exposure. Learning how to check the pollen count each day, like using the MapMyAir tool, is an important step in reducing symptoms in those with allergies.


Understanding Pollen Counts

What does pollen count mean? Understanding the pollen count goes a long way in helping allergy sufferers reduce — or eliminate — their reaction to this allergen.

Pollen counts measure the grains of pollen per cubic meter of air. A standardized calculation is used to determine the pollen count for each 24-hour period for a specific location. Many weather forecasters now include a pollen component in their daily projections, along with air quality index information.

Most pollen allergy sufferers do not need an official pollen count forecast to know when the allergen is thick in the air. Their symptoms will likely let them know whether it is a low, standard, or high pollen day.

Can high pollen count cause sore throat? Can high pollen count cause shortness of breath? The answer to both of those questions is yes. Pollen can also cause the following not so fun symptoms:

  • Cough
  • Fatigue
  • Itchy, red, watery eyes
  • Nasal congestion
  • Postnasal drip

On days when the pollen count is the highest, it is best to stay indoors and use an air purification system to keep your indoor air clean and free of any pesky allergens.


Calculating Pollen Counts

How is pollen count calculated? The pollen count is calculated using an air-sampling device called a rotarod, which collects pollen for a 24-hour period.

The rotarod uses clear silicone rods coated in grease to attract and retain pollen. Scientists take the collected material from the rods and analyze it. They look for pollen types and their concentration levels.

Pollen tracking is not handled by any government agencies. Private companies conduct pollen counts and provide the data to the public.

To become a pollen counter, you must receive certification, which requires passing an exam. Certification programs are available through the National Allergy Bureau [3]. The bureau also offers training for pollen counters before they take the test.

There are three categories for pollen counts: low, standard, and high. Grasses, molds, trees, and weeds all have different levels of low, standard, and high counts.


What Is Considered A High Pollen Count?

  • Grasses: 20 to 199
  • Mold: 13,000 to 49,000
  • Trees: 90 to 1,499
  • Weeds: 50 to 499

What Is Considered A Low Pollen Count?

  • Grasses: 1 to 4
  • Mold: 1 to 6,499
  • Trees: 1 to 14
  • Weeds: 1 to 9

What Is Considered A Standard Pollen Count?

Standard pollen counts are subjective. Pollen counters average collected data to determine standard amounts for grass, mold, trees, and weeds.

What many pollen counters have noticed is that warmer temperatures drive up the amount of pollen in the air [4], which spells bad news for those with pollen allergies.

Climate change has brought about longer pollen seasons, increasing the length of time allergy sufferers must practice allergy-reduction tactics like taking antihistamines and avoiding peak pollen release times by staying inside and using  air purification systems.


Factors That Affect Pollen Count

What affects pollen count? Why is the pollen count so high? When it rains, does the pollen count go down? What time of day is tree pollen count highest? The answer to each of these questions reveals that certain factors like rain, temperatures, and wind affect daily pollen counts.

As a rule, dry, hot, windy days bring higher pollen counts. Pollen can travel further on windy days, and without moisture to deter it, pollen can stick to almost any surface.

Cool, damp, and rainy days have less pollen circulating in the air. Unfortunately, that does not mean they are better for your allergies.

Rain can make pollen worse by nourishing the plants that produce it. Warm and wet seasons stimulate plant growth, and when plants grow, they pollinate more [5].

Pollen is not just affected by the weather conditions. Time of day also plays a role in how much pollen is released.

When are pollen counts the highest? On an average weather day, pollen counts rise during the morning and peak about midday. They then gradually fall into the evening and overnight hours. If you have pollen allergies, staying indoors with an air purification system during the peak release times can help lessen your symptoms.

Another concern for pollen allergy sufferers is tree pollen. It is the most common outdoor allergen and is most active in the spring. What time of day is tree pollen count highest? Like other outdoor allergens, tree pollen is the highest in the mid-afternoon.


Pollen Counts By Time Of Day

Does pollen count decrease at night? As a rule, pollen counts peak in the mid-afternoon when the temperatures are the hottest and decrease in the evening and overnight hours when temperatures cool down.

That does not mean you will be free from allergy symptoms at night. If you spend a lot of time outdoors during the peak pollen times, your body can still react to it hours later when you plan to go to sleep.

Another factor for worsening nighttime allergy symptoms is bringing pollen indoors with you. If you are outside on high pollen count days, consider showering and washing your hair before bedtime to remove any pollen.

Keep the clothes you wore away from the main living area until they can be washed. Also, running an air purifier can help clean your indoor air of any airborne pollen that managed to break free.


How To Reduce Pollen Allergens

Some people with severe pollen allergies get immunotherapy (allergy shots) to help lessen their symptoms. Others limit outdoor activity during peak pollen times and take antihistamines.

There is another thing you can do to ensure pollen does not make its way indoors, where it can trigger your symptoms 24/7: use a high-quality air purification system to improve indoor air quality.

There are plenty of air purification systems available, each with a different level of effectiveness for removing indoor air pollutants like pollen. In a Clemson University study of air purifiers, Oransi was ranked number one by the experts out of four leading air purifiers on the market for its ability to remove bacteria, dust, mold, and pesky pollen.

Oransi’s air purifiers include filters with some of the highest MERV ratings available for in-home purification products. MERV (Minimum Efficiency Reporting Values) ratings range between 1 and 20.

The higher the MERV rating on a filter in an air purifier, the better it is at removing indoor air pollutants including pollen. MERV ratings between 17 and 20 are the highest a filter can rank.

Air purification systems with 17 to 20 MERV ratings are usually reserved for pharmaceutical manufacturers, orthopedic surgery facilities, and in environments where there are carcinogenic and radioactive materials. Filters with a 13 MERV rating are suitable for most home environments where pollen is present.

Every Oransi air purifier comes with a MERV rating of 13 or higher. Customers can enjoy free shipping of Oransi products throughout the US when they order online.



[1] Asthma and Allergy Foundation of America,,people%20have%20seasonal%20pollen%20allergies.

[2] American College of Allergy, Asthma, and Immunology (ACAAI),

[3] National Allergy Bureau, Become a Counter,

[4] Anthropogenic climate change is worsening North American pollen seasons, Anderegg, W., et al, PNAS February 16, 2021,

[5] Studying plant-pollinator interactions in a changing climate: A review of approaches, Diane L. Byers, 2017 June 5,