Particle size matters for people who are sensitive to house dust mites because the smaller the faecal particle carrying active enzymes, the deeper it can travel into the lungs, even reaching delicate areas of gas exchange. To date scientists have identified 7 different active enzymes from house dust mites. In general, inhaled particles above 10 microns will land on the trachea or bronchi while smaller dust (below 10 microns) has the potential to reach and be deposited in the alveoli. The alveoli is the last stop in the branches of our lungs and where gases are exchanged.
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