The effect of PM10 on allergy symptoms in allergic rhinitis patients during spring season.

Background: Asian sand dust (ASD) that originates in the Mongolian Desert in the spring induces serious respiratory health problems throughout East Asia (China, Korea, Japan). PM10 (particulate matter with an aerodynamic diameter <10 μm) is a major air pollutant component in ASD. We studied the effects of PM10 on allergy symptoms in patients with allergic rhinitis during the spring season, when ASD frequently develops.
Methods: We investigated the changes in allergic symptoms in 108 allergic patients and 47 healthy subjects by comparing their 120-day symptom scores from February to May 2012. At the same time, the contributions of pollen count and PM10 concentration were also assessed. We also compared symptom scores before and 2 days after the daily PM10 concentration was >100 μg/m3.
Results: The PM10 concentration during the 120 days was <150 μg/m3. No significant correlations were observed between changes in the PM10 concentration and allergic symptom scores (p > 0.05). However, allergic symptoms were significantly correlated with outdoor activity time (p < 0.001).
Conclusions: These results demonstrate that a PM10 concentration <150 μg/m3 did not influence allergy symptoms in patients with allergic rhinitis during the 2012 ASD season.