The results of a new study published in the online journal PLOS One have revealed that in the next century the number of people who suffer from pollen allergies will increase due to climate change.

Pollen allergies are already much more common than they were 100 years ago, but scientists are warning that grass pollen and allergen exposure are likely to increase by up to 200% over the course of the next century due to climate change.

The researchers from the University of Massachusetts Amherst have concluded that increase in the concentrations of ground-level ozone and carbon dioxide will lead to an increase in the number of people who suffer from pollen allergies, as well as more extreme conditions for those who already suffer from allergies.

The reason behind this is the fact that carbon dioxide in the air helps plants grow and the greater the concentrations in the air, the greater the number of plants on the ground.

To come up with these results, the researchers examined grasses in four enclosed tanks, which allowed them to have control of the atmosphere of each environment. In one of the tanks, the levels of carbon dioxide were raised to twice the levels present in today’s air, while the ozone concentrations were maintained at the same levels. In the second tank, the ozone levels were raised from 30 to 80 (parts per billion) and carbon dioxide kept at normal levels, while in the third tank both gases were raised. The fourth tank served as the control tank, which housed the atmosphere of today.

The results of the experiment showed that the increased carbon dioxide levels raised the production of pollen by 53%, while ozone did not appear did not modify the production of pollen in the plants in the tanks. Normally, ozone has a tendency to stunt plant growth. The conclusion of this study is that in following years, the number of people suffering from pollen allergies will increase.

Pollen allergies in humans cause wheezing, headaches, watery eyes, itching and difficulty breathing. Almost 20% of Americans are suffering from pollen allergies and in the following century the number of people suffering from pollen allergies will increase.

Christine Rogers, from the University of Massachusetts Amherst School of Public Health and Health Sciences, revealed that:

The implications of increasing CO2 for human health are clear. Stimulation of grass pollen production by elevated CO2 will increase airborne concentrations and increase exposure and suffering in grass pollen-allergic individuals.