How air pollution impacts pollen allergy

According to a 2021 study, there are an estimated 400 million people who suffer from allergies (or allergic rhinitis). Not only do allergies impact a person’s quality of life, but they also put a burden on our health systems, responsible for 2400 € per year in health care costs for untreated allergy sufferers in the European Union alone¹. This number will continue to increase as air pollution and climate change contribute to longer and more severe pollen seasons. Read on to learn more.

What is pollen allergy?

Pollen, a powder consisting of small pollen grains, is essential for the sexual reproduction of flowering plants. Pollen is released by the male part, or stamen, of a flowering plant, and is transported to the female part, or stigma, using various vectors. Some of these vectors may include:

1. Wind (commonly used by grasses to reproduce)
2. Water
3. Living organisms (pollinators) including insects, mammals, birds, and even some reptiles

Allergy to pollen, often one of the main sources responsible for “seasonal allergic rhinitis”, is common. It occurs when the immune system mistakenly identifies an allergen as harmful and, thus, initiates a defensive response and releases chemicals, including histamines.

Symptoms of pollen allergy vary greatly depending upon the individual but range from mild discomfort (itchy eyes, nose, and throat; sinus congestion) to severe, sometimes responsible for triggering asthma attacks in asthmatics and causing difficulty breathing. It also can severely impact a person’s quality of life by making it difficult for them to go outdoors².

Pollen is technically considered to be a type of particulate matter (PM). However, since intact pollen particles typically have a size of greater than 10 μm, they are too large to fall into the PM10 category. It is more problematic when pollen particles fracture down to a much smaller size, sometimes small enough to fall into the PM2.5 category, meaning that they can easily gain access into our respiratory systems³.

¹ Annual pollen seasons showing peak pollen season (the black bar) and early and late seasons (the thin black arrow) according to the Medical University of Vienna, Austria

Pollen and air pollution

Multiple studies have presented findings that come to the following conclusion: urban residents who are more regularly exposed to air pollutants experience more respiratory allergies than those living in rural areas.

One 2018 study speculates that chemical pollutants facilitate the release of pollen allergens and augment allergenic potential by the chemical pollutants damaging pollen’s cell walls. A damaged cell wall causes the pollen to be more easily released into the environment, gaining quicker and easier access to the lower respiratory tract through respiration. The study mentions that the severity by which an individual is affected depends on certain factors: concentration of environmental pollutants, duration of exposure, ventilation present within an indoor space, climatic conditions, and the more recently discovered interaction between pollen allergens and air pollution⁴.

Other studies have discovered that air pollution increases the allergenicity of certain types of pollen. Certain plants, such as the Cupressus arizonica Cyprus, react to the presence of air pollution with a defensive response by releasing higher quantities of pollen^5,6.

Two further studies found that certain air pollutants in particular were responsible for causing more severe allergy symptoms: the first study points a finger at nitrogen oxide and PM2.5, discovering that places that are more heavily polluted with PM2.5 were associated with a 17% higher risk of residents experiencing severe allergic rhinitis⁷. The second study puts the blame more on ozone, finding that it intensifies the symptoms of pollen allergy sufferers especially during the pollen seasons of birch, grass, and ragweed⁸.

How pollen allergy sufferers can protect themselves

Some of the above studies have noted that the results of their studies should make it easier for allergy sufferers to be better informed during allergy season: by using local data provided by air quality trackers reporting on pollutant levels in real-time, those experiencing allergies will be able to be aware of peak levels of airborne allergens.

While this is certainly useful, how do pollen allergy sufferers manage their symptoms once the allergens are already in the air? How do they protect themselves from breathing in pollen that is expected to increase in quantity and allergenicity with the presence of air pollution? Here is a list of a few things you can do to help⁹:

1. Track air pollutant and allergen levels in your neighbourhood. In the UK, DEFRA has created a site that allows you to track your local air quality in real-time: https://uk-air.defra.gov.uk/. Use this information to stay informed, and avoid going outside or exercising when pollution is high.
2. Drink herbal tea. Certain teas, like those with peppermint and honey, can work as decongestants and anti-inflammatories.
3. Wear a mask. Allergy masks are great for protecting your lungs from pollen and other allergens like dust or mould.
4. Change your clothes and wash your face and hair after being outdoors. This will avoid pollen from being tracked inside your home. Showering before bed is also useful to avoid pollen from being transferred from your hair and skin to your pillow. 
5. Use saline solution. This helps to relieve sinus symptoms like congestion. You can even make your own using 3 teaspoons of non-iodised salt and 1 teaspoon of baking soda. When ready to use, mix one teaspoon of the mixture into 240 ml of water that has been previously boiled then let to cool.
6. Purchase an air purifier.

Protect yourself from pollen and other respiratory allergies with Eoleaf

Air purifiers containing a HEPA (high efficiency particulate air) filter are the only devices that are proven to clean the air of allergens. As mentioned above, intact pollen particles are usually larger than 10 µm, but since these particles can rupture, a HEPA filter will be able to catch any allergen and fine particle down to a size of 0.01 µm. All Eoleaf devices come equipped with HEPA-certified filters and 7 other filtration technologies including activated carbon filters, UV sterilisation, and ionisation, enabling a broad spectrum of action on most varieties of allergens and pollutants.

References

¹ Berger, M., Bastl, M., Bouchal, J., Dirr, L., & Berger, U. (2021). The influence of air pollution on pollen allergy sufferers. Allergologie Select, 5(01), 345–348. https://www.dustri.com/article_response_page.html?artId=188991&doi=10.5414/ALX02284E&L=0

² What is pollen. The University of Western Australia. (2011). Retrieved April 19, 2023, from https://www.uwa.edu.au/study/-/media/Faculties/Science/Docs/What-is-pollen.pdf

³ Boose, Y. (2022, August 2). Air Pollution, pollen & allergies: What's the link? Pollen & Seasonal Allergy. Retrieved April 19, 2023, from https://blog.breezometer.com/pollen-api-air-pollution-difference/

⁴ Sedghy F, Varasteh AR, Sankian M, Moghadam M. Interaction Between Air Pollutants and Pollen Grains: The Role on the Rising Trend in Allergy. Rep Biochem Mol Biol. 2018 Apr;6(2):219-224. PMID: 29766006; PMCID: PMC5941124.

⁵ Cortegano I, Civantos E, Aceituno E, del Moral A, López E, Lombardero M, del Pozo V, Lahoz C. Cloning and expression of a major allergen from Cupressus arizonica pollen, Cup a 3, a PR-5 protein expressed under polluted environment. Allergy. 2004 May;59(5):485-90. doi: 10.1046/j.1398-9995.2003.00363.x. PMID: 15080828.

⁶ Suárez-Cervera M, Castells T, Vega-Maray A, Civantos E, del Pozo V, Fernández-González D, Moreno-Grau S, Moral A, López-Iglesias C, Lahoz C, Seoane-Camba JA. Effects of air pollution on cup a 3 allergen in Cupressus arizonica pollen grains. Ann Allergy Asthma Immunol. 2008 Jul;101(1):57-66. doi: 10.1016/S1081-1206(10)60836-8. PMID: 18681086.

⁷ Burte, E., Leynaert, B., Marcon, A., Bousquet, J., Benmerad, M., Bono, R., Carsin, A.-E., de Hoogh, K., Forsberg, B., Gormand, F., Heinrich, J., Just, J., Nieuwenhuijsen, M., Pin, I., Stempfelet, M., Sunyer, J., Villani, S., Künzli, N., Siroux, V., … Jacquemin, B. (2020). Long-term air pollution exposure is associated with increased severity of rhinitis in 2 European cohorts. Journal of Allergy and Clinical Immunology, 145(3). https://www.jacionline.org/article/S0091-6749(19)31636-7/fulltext

⁸ Berger M, Bastl M, Bouchal J, Dirr L, Berger U. The influence of air pollution on pollen allergy sufferers. Allergol Select. 2021 Dec 1;5:345-348. doi: 10.5414/ALX02284E. PMID: 34870078; PMCID: PMC8638356.

⁹ Kim, K. (2020, January 12). Spring sneezing: 7 ways to protect yourself from pollen allergies. The Red and Black. Retrieved April 19, 2023, from https://www.redandblack.com/culture/spring-sneezing-7-ways-to-protect-yourself-from-pollen-allergies/article_c396090e-566b-11e9-9394-334cdfc48118.html