Is pollen a pollutant? (by Diego Fdez-Sevilla)
This is a question that I have received and here I present the answer that I have given so I would like to share my thoughts about it.
Pollen from grasses, trees, and weeds is the wonderful substance that allows plants to reproduce, but it is also responsible for numerous allergic reactions people experience. Although pollen is found naturally in the air, human activities and choices can increase the amount of pollen in our air, and in turn, can cause people to have more severe allergic reactions. Because human activities can increase the amount of pollen in our air and cause adverse health effects, some people view pollen as an air pollutant.
People commonly treat their allergies by avoiding situations where they might have an attack, by using dehumidifiers and air filters. But, by becoming familiar with the source of you allergies, you can also begin to make choices that can prevent the severity of your attacks. The number of pollen particles released into the air are studied and measured by the field of “Aerobiology” performing a “pollen count”. Pollen counts tell you the number of pollen grains per cubic meter of air. They can also tell you which tree, grass, or plant the pollen came from. Different plants and trees produce different amounts of pollen and knowing which plants are the largest contributors to your allergies can influence what flowers and trees you and your community chose to plant.
I think that there is a good explanation about the situation nowadays in this site which can be applied not only to USA but worldwide:
Air Pollution: Smog, Smoke and Pollen: “Ozone smog forms when pollution from vehicles, factories, and other sources reacts with sunlight and heat. Increasing temperatures speed this process and result in more smog. Added to the mix are ragweed and other allergens in the air — which are expected to worsen as rising carbon dioxide levels cause plants to produce more pollen.”
As part of the topic I would like to mention that the European Commission developed a new regulation for Air Quality standards in 2009 which did not include the atmospheric monitoring of biological particles such as pollen and spores despite of being of high relevance in the health impact assessment for atmospheric environments outdoors.
The justification behind this decision was that their presence in the atmosphere was not the result of man-made activity. However, there is enough evidence to support that the impact that pollen and spores concentration in the air has in our health after exposure is the result of combining factors such as:
- an increased presence of those particles in our atmosphere due to man induced changes in climatic conditions (global climate change and strong impact of urbanization increasing the so called “heat island effect”),
- the increased presence of ornamental plant species in our communities with recognized allergenic pollen as a result of arbitrary decisions and,
- the increasing allergenic behaviour of pollen as a result of interacting with man-made pollutants present in the atmosphere.
If we want to characterize the hazardous potential of the atmospheric load in our health I would consider relevant to monitor altogether pollen with CO2, Ozone, SOx, NOx, VOCs, etc as health impact pollutants. Furthermore, it is of my believe that measures taken to monitor pollen atmospheric concentrations and allergenic conditions would allow to implement such information in health strategic decision making (bringing awareness to public and medical doctors to adopt measures beforehand). And also, it would contribute to evaluate the impact of human decision making which could worsen or improve atmospheric environmental conditions. (check also https://diegofdezsevilla.wordpress.com/tag/pollen/)
Considerations by the EPA about outdoor air pollution includes in their assessments the role played by pollen from plants, crops and weeds since it may worsen chronic respiratory diseases, such as asthma.
For a more in depth reading I would suggest the following article (notice it is from 1991 so you can see this topic comes from some time ago already. The publications coming after confirm and increase the data):
The significance of air pollution in aerobiology. M. D. Lebowitz, M. K. O’rourke Grana Vol. 30, Iss. 1, 1991
Also, I leave you articles in which it is quantified the impact of anthropogenic climate change on pollen concentrations and the impact of ornamental plantings. They are just an example of scientific input in the field mentioned. Any person interested in further research can follow references and citations from and, including, these studies.
About the impact of anthropogenic climate change on pollen concentrations:
* Review of the Impact of Climate Variability and Change on Aeroallergens and Their Associated Effects (Final Report) by the EPA.
* An article in which I am co-author:
Assessment between pollen seasons in areas with different urbanization level related to local vegetation sources and differences in allergen exposure. Rodríguez-Rajo, F.; Fdez-Sevilla, D.; Stach, A(†). & Jato, V. (2010). Aerobiologia, Vol 26-1, 1-14.
About the impact of ornamental plantings.
*Urban green zones and related pollen allergy: A review. Some guidelines for designing spaces with low allergy impact. Paloma Cariñanos, Manuel Casares-Porcel. Landscape and Urban Planning, Volume 101, Issue 3, 15 June 2011, Pages 205–214.