Statistical Analysis
REGRESSION
Linear regression
models were used to estimate the impact of air filter use (as a dichotomous
variable) on in-vehicle pollutant concentrations, adjusting for concurrent
rooftop concentrations. Linear mixed models with random intercepts
for subject were used for all health analyses to account for repeated
measurements within subjects; pollutant coefficients were scaled to
reflect interquartile range (IQR) increases in pollutant levels (BC
= 1818 ng/m