The nasal filter more than halved a number of the most common allergic symptoms such as sneezing, runny nose and watery eyes.

"The nasal filter more than halved a number of the most common symptoms such as sneezing, runny nose and watery eyes. And when participants initiated use of the filters before symptom onset, the effects were even more pronounced, which we see as an indication of the nasal filter’s preventive effect," says professor Torben Sigsgaard at Aarhus University, Denmark.
The study showed that sneezing and watery eyes were reduced by 100% over the whole day, while runny noses were decreased by 84% compared to the placebo. These symptom reductions when using nasal filters were greater than what had been shown in similar park studies regarding medical treatments.
"Moreover, the subjects with nasal filters did not feel worse, even though the pollen levels on day two were markedly higher than those on day one. This suggests that the nasal filters will become increasingly beneficial as pollen levels increase," said Peter Sinkjaer Kenney, the inventor of the filter and a PhD student at the University.
Source-Medindia