# How can I perform the assumption of the lmfit function from limma package?

I'm doing a DNA methylation analysis using the limma package. The idea is to explore if there is a dose-response between exposure (pm2.5) and methylated CpG sites. Here is my code. I would like to know how can I do the linear assumption using the limma package.

Thanks

dx <- with(phenoData.final, model.matrix(~ work_duration + Age + BMI + race))