For children with asthma, exposure to indoor air pollution increases the risk of a serious asthma exacerbation, which can be life-threatening. Interventions aimed at improving indoor air quality, including use of a portable air cleaner with a high-efficiency particulate air (HEPA) filter, can reduce this risk, but the effectiveness, feasibility and acceptability of HEPA air cleaners varies by setting. In collaboration with a community health worker (CHW) delivered asthma education program, the investigators are conducting a randomized clinical trial to evaluate the effectiveness of HEPA air cleaners to improve indoor air quality and child asthma health in South King County of Washington state, a vulnerable community impacted by air pollution from airports and highway traffic. Key features of the Airports, Air Quality and Asthma (AAA) design include integration of CHWs into study procedures, including CHWs recruited from community-based organizations, into multiple aspects of the trial protocol. The investigators aim to recruit up to N=60 children with asthma randomized into intervention and control groups in a 1:1 ratio, conduct baseline assessments of indoor air quality and airway health, and collect repeated assessments of air quality and airway health during the three-month intervention period and after the trial concludes. Study findings will inform future approaches to integrate HEPA air cleaners into existing CHW asthma education programs in this and similar communities.