We've always considered it safe to garden outside. I am more worried about the birds than myself. It might be silly. The outdoor birds seem quite healthy.
The soil on this place has not been treated with any chemicals in 39 years. We only fertilize with llama manure from our own animals. It has been 10 years since the fruit trees were sprayed with chemicals for bugs.
The farmers around us use whatever chemicals, fertilizers, bug killers, and chemically treated seeds they want to use. They were applying anhydrous amonia yesterday, which is what prompted me to ask the question.
I'd have to look at the plot plan to tell you how far away the fields are. It was really windy yesterday.
I suspect even organic gardners who do that sort of thing for a living only have control over their own plots of land, so even organic stuff I would buy wouldn't be guaranteed to be less exposed than stuff I would grow. :shrug:
I find I worry all the time about the birds and their health. They are so tiny and their systems are more sensitive.