Asian dust storm (ADS) contains airborne particles that can have negative effects on health in Asian countries. The objective of the study was to investigate the association of ADSs with asthma and airway inflammation in western Japan. We designed a telephone survey to assess the influence of an ADS on upper and lower respiratory systems in adult patients with asthma. The patients also recorded scores for daily upper and lower respiratory tract symptoms and measured morning peak expiratory flow (PEF). Production of interleukin-8 was assessed in THP-1-derived IL-8 reporter cell line (THP-G8) cells that were exposed to airborne particles collected during ADS days. Our results showed that 11–22% of patients with asthma had worsening of lower respiratory tract symptoms on ADS days. The ADS also had a significant negative association with pulmonary function of patients with asthma. However, emergency treatment for augmented symptoms caused by the ADS was not needed because exacerbation of asthma was mild in adult patients. Comorbid allergic rhinitis has been suggested to be an important determinant of worsening of lower respiratory symptoms during an ADS in patients with asthma. Airborne particles collected on ADS days induced interleukin-8 in THP-G8 cells, but this effect was not observed for the original soil sample of the ADS. Thus, exposure to an ADS aggravates upper and lower tract respiratory symptoms in patients with adult asthma and ADS airborne particles may increase airway inflammation through elevation of interleukin-8.