Dear Stata users,

I would like to ask which stats I should use. I have health outcomes data (continuous) for 2 years, 1-year before and after interventions (Three types of interventions to improve air quality). I don't have a control group. I used t-tests to see how air quality was improved.
What I've learned so far, I'm trying to use 1) intend to treatment or 2) mixed effect model using "xtreg" after reframing the dataset to panel dataset, to see the effectiveness of interventions on health outcomes. Or can I use "DID" analysis without a control group, just comparing each of three intervention groups?

Could you please give me any recommendations?
Many thanks.