HEPA, PM2.5, and Cardiometabolic Health

Inclusion Criteria:

* Age between 65 and 84 years old;
* Nonsmoker for at least 1 year;
* History of BMI ≥ 25 kg/m2 in the past based on EMR information;
* Either an English or Spanish speaker;
* Live in the Los Angeles County.

Exclusion Criteria:

* History of diabetes (both type 1 and type 2) or degenerative disease of the nervous system (Alzheimer's disease or dementia);
* Currently have active cancer treatment;
* The residential house has already had HEPA filters;
* Participants will move out of the current house in the next 2 years;
* Participants will spend more than one month living outside the primary home;
* Have any health conditions that prohibit collecting health and covariate data and biospecimen;
* The residential houses are not feasible for setting up air purifiers and air pollutants monitors;
* Have high blood glucose from finger stick test (\> 200 mg/dL).