Fig 1.
STROBE Flowchart of the two-stage sampling and participant selection process.
The diagram illustrates the recruitment stages: Stage 1 (Area-level) involved purposive site selection (Sub-Stages 1–2), and Stage 2 (individual-level) involved participant identification, pre-screening, stratified random sampling for formal invitation. The final analytical sample was established after clinical validation, strict adherence to ATS/ERS 2019 standards, and frequency matching to ensure healthy, comparable groups.
Table 1.
AQI (Air Quality Index), PM2.5 and PM10 Concentrations in Preliminary Measurement Areas.
Table 2.
Demographic and Anthropometric Characteristics of Study Participants by Data Collection Location.
Table 3.
Summary of Statistical Test Results for Inter-Group Characteristic Comparisons.
Table 4.
Summary of Statistical Tests for FEV1, FVC, and FEV1/FVC Variables.
Table 5.
Pearson Correlation and Spearman’s rho Matrix between PM₂.₅ Exposure, Covariates and Lung Function Variables in the Older adults.
Table 6.
Summary of Multivariable Linear Regression Analysis.
Table 7.
Residual Normality Tests for Multivariable Linear Regression Models.