I am conducting an air pollution case-crossover analysis and I'm in the midst of adding in pertinent weather variables. I cast a wide net and downloaded data from NOAA, National weather service and a few other sources. The problem is that for each variable, there are multiple versions of it. For example, we have maximum temperature, minimum temperature, apparent temperature, etc.
Are there any diagnostics I can employee to work out which variables I can use in my time series? Is there also any agreed upon variable? For example, is there literature out there confirming that perhaps Tmin should generally be used for such an analysis? Any resources or studies you may able to direct me to would be really helpful!