• The primary outcome for this study is reduction in PM10 and PM2.5 over the 6 month follow-up. [ Time Frame: 6 months ] [ Designated as safety issue: No ]
  

• Secondary outcomes include ETS reduction behavior change (i.e. smoker is smoking outside of home, child not sitting with smoker, reduction in number of household smokers), symptom free days and health care utilization measures. [ Time Frame: 6 months ] [ Designated as safety issue: No ]
  

150 children aged 6-12 years who reside in Baltimore and have a smoker in the household are to be enrolled in this study. All children will be randomized into three groups: HEPA air cleaners plus ETS/Indoor particulate behavior management, HEPA air cleaners and a standard asthma education and a standard asthma education group with delayed HEPA filter use. The HEPA air cleaner plus ETS/Indoor particulate behavior management intervention group will receive four home visits by a health coach to assess motivation for parental behavior change and then assist the parent to reduce/eliminate their child's exposure to ETS in the home. The intervention is based on the social cognitive theory that utilizes behavior modification techniques (e.g., modeling, reinforcement, self-monitoring, feedback and rehearsal) to change health behaviors. Families in this group and the HEPA air cleaner only group will receive two HEPA air cleaners to use over the 6-month follow-up period and three home visits for standard asthma education. Use of air cleaners will be electronically monitored to determine level or "dose" of air cleaning used by families. The standard asthma education group (delayed HEPA Filter group) will receive three home visits to deliver basic asthma education. All children receive a baseline home inspection, 7-day home PM exposure monitoring, home dust allergen collection, skin testing, urine cotinine, spirometry, serum eosinophilia and exhaled NO testing. Caregivers of each child will be interviewed at baseline and at the 6-month follow-up regarding ETS reduction behaviors in the home, symptom frequency, asthma control, other environmental exposures and health care utilization outcomes. The primary outcome for this study is reduction in PM10 and PM2.5 over the 6 month follow-up. Secondary outcomes include ETS reduction behavior change (i.e. smoker is smoking outside of home, child not sitting with smoker, reduction in number of household smokers), symptom free days and health care utilization measures. If successful, this intervention could have significant clinical and public health applications for pediatric asthma management in children with persistent asthma and high ETS home exposure.