by Kaylee Anderson
Hayfever is one of the most common allergic conditions, affecting as many as 10 million people in the United Kingdom. It is most well-known to be triggered by ragweeds in the United States and by grasses in the UK. Ragweeds were introduced to Europe in the 19th century, rapidly spreading by 1940.
It is believed that the threshold for clinical symptoms of hayfever is as low as 1-3 ragweed pollen grains/m3, which is significantly lower than other well-known pollen allergens, like grass and birch. Continue reading