There are many factors that influence air quality: city pollution, time of year depending on the use of heating in winter or times when pollen proliferation is more common, such as in spring. Therefore, if you are allergic or suffer from respiratory diseases such as asthma, knowing the state of the air can help alleviate the harmful effects on our health. It is true that wearing a mask outdoors can help alleviate the effects of pollution, especially when it comes to pollen, ash, or larger particles. Inside, PUROH solves all these problems.