Epidemiological studies have found associations between exposure to fine particulate matter (PM2.5) or ozone (O3) and indices of acute cardiopulmonary morbidity and mortality. Most of these studies used outdoor pollutant concentrations as exposure surrogates and didn’t account for building-to-building and temporal variations in indoor infiltration, and variations in time spent in different indoor locations. We developed an exposure model called TracMyAir, which is an iPhone application that determines multiple tiers of individual-level exposure metrics in real-time for ambient PM2.5 and O3 using outdoor concentrations (from regular monitoring network or low-cost air sensors), home building characteristics, weather, time-locations, and time-activities. TracMyAir includes a microenvironment (ME) model (MicroTrac) based on time-resolved smartphone geolocations, and inhaled ventilation models based on physical activity data from smartphone and smartwatch accelerometers and heart rate sensors. TracMyAir calculates several tiers of exposure metrics: personal outdoor concentrations (Cout, Tier 1); residential air exchange rates (AER, Tier 2); infiltration factors (Finf_home, Tier 3), indoor concentrations (Cin_home, Tier 4); personal exposure factors (Fpex, Tier 5), exposures (E, Tier 6), and inhaled doses (D, Tier 7). We applied TracMyAir to determine hourly PM2.5 and O3 exposure metrics for three panel studies with nine participants living in central North Carolina: one study with 216 participant-hours during November 2019, another study with 648 participant-hours during September–October 2020, and third study with 859 participant-hours during July–August 2022. The TracMyAir predictions showed considerable temporal and house-to-house variability of AER, Finf_home, and Cin_home (Tiers 2–4), and person-to-person variability of Fpex, E, and D (Tiers 5–7). Our study demonstrates the capability of integrating air quality and time-activity sensors and models to estimate individual-level ambient PM2.5 and O3 exposure metrics, in support of epidemiologic studies and public health strategies to help individuals reduce their exposures to ambient air pollutants. The exposure metrics were evaluated in their ability to characterize the spatial and temporal variations of multiple ambient air pollutants across the study area. This research will be used for improving exposure assessments in future air pollution epidemiology studies, and for informing future multipollutant exposure analyses.