"During the past few decades, a growing body of evidence points to an association between urbanization and the rising trend in allergic diseases, suggesting air pollution as a major cause for this trend. Studies have shown that people living in urban areas experience more severe and prevalent allergic symptoms than those in rural areas." - An excerpt from a fully referenced article on the correlation between air pollution and pollen allergies link at the end if this post.

Aside from agricultural fertilizers this is another aspect to my allergies that I have theorized for a good few years or more based simply on observations coupled by experience of the outdoors and acute sensitivity to environmental changes. Today I decided to do some research to back this up and this was the first article amongst others that I uncovered.

"The interaction between air pollutants and pollen grains might damage the pollen cell wall, increasing the amount of allergens released into the environment. Experiments on Platanus orientalis pollen performed by Lu et al. revealed new kinds of particles on the pollen surface after exposure to a mixture of pollutant gasses . Chehregani et al. confirmed the accumulation of sub-micronic particles on the surface of Zinnia elegans pollen grown in the presence of pollutants, which resulted in an increase in allergen release into the environment and increased pollen allergenicity."

There are also references in this article that suggest an increase in the plant pollen's own defences due to air pollution and unfavourable conditions which results in a higher allergic response to pollen grains, see excerpt below:

"Recently, the effect of air pollution, as an environmental stressor, on allergens categorized as pathogenesis-related (PR) proteins, has attracted much attention. These proteins are part of a plant defense system that plays a key role in protecting plants from undesirable conditions, such as pathogen attacks, drought, and freezing temperature. To date, few studies have examined the impact of air pollution on these proteins. For instance, Cortegano et al. reported that Cup a 3 allergen, a PR protein family member, was more abundant in polluted than in unpolluted conditions, a finding confirmed by Suarez-Cervera in 2008. These studies noted that cypresses increase allergen expression as a defense strategy against pollution, which can also affect pollen allergenicity."

This would explain why I suffer most near cities, towns, and busy roads during the summer months. Fertilisers from agriculture can also bind to the pollen and it makes perfect sense that ammonia could be one of them.

Whilst pollen might be the carrier, we have created our own problems through industrialisation and we can no longer hide from the impact we are having upon the earth. It will only become worse unless action is taken - so make a stand in your daily choices and let's change this world together.