https://www.nejm.org/doi/full/10.1056/NEJMc2004973?query=featured_home
The actual study - so, if you are spraying your items with aerosol COVID-19, the results they give you are valid. If you are touching a box, or coughing on a box (droplets not aerosol) then you really have nothing to compare to at this point. The half life volume of an aerosol-spraying is not going to be the same as for a touch. Not sure about a droplet.
Think of it this way. A person with COVID-19 coughs on his hand. 100 particles of virus get on that hand. The hand touches a box. Not all 100 particles are going to get on that box. If 50 do, half of them are going to die in 3.5 hours. Now you're down to 25. But the study doesn't cover any of this. It doesn't say how much is transmitted in a touch (or give a percent, but I haven't read the original top to bottom, just the letter they sent)