Weed in jar

The two top thc killers are light and oxygen. Store in an air tight container in the dark.

 

It's probably not that it's smelling more or like "filling the jar with smell", there's only so much space.
It's more likely that you'vve just kept it in a more optimal environment than normal...and those bags you were using weren't as smell free and air tight as you thought. Smell can travel through a standard sandwich bag/ziploc really easily, it literally travels through it.
You were probably just used to the dispersed level of smell without realising it..it's likely someone that entered your place that doesn't smoke weed probably would have smelled it to some point.
So when you've got it in a jar, you don't smell this at all...so when you open it up, you get what seems to be a stronger effect.
See when you're keeping it airtight in a container/jar, you're actually (if not specifically via deliberate, timed burping) kind of putting it through a bit of a cure.
What does curing do?
So basically you slowly draw out liquid content from the centre of your bud/s to the outside where it disperses...there's probably a more technical description but that's basically it.
Why?
*Quality is retained, because it's like "extra drying".
*Long term storage, will prevent spoilage (unless mould or other factors are already in play)
...and most importantly to your case...
*Flavour, and SMELL are improved - it's a smell that's what the bud should actually be having...and often isn't, because a lot of sellers don't dry properly, and they NEVER cure.
So what you're doing is kind of both storing it better, trapping a bit more smell (yes), and semi-curing it.
It smells stronger and better because of this and the comparison in storage methods.

This is nothing to do with anything being laced.
Trust me.
I think most stories I ever heard about this were just parents/schools attempts to dissuade younger people from using weed in the first place, if you ask me.
At most if something is ever in your weed that shouldn't be and you have been alerted to this by smell, it'll be unflushed nutrients/flowering boosters, PGRs (though I hope not) and the like, which are not all good things for you to be ingesting...but it happens. A lot. Won't kill you but you wouldn't go have a drink of plant feed would you?
If it's "real" drugs or glass or some other dangerous bullshit mixed in, you'll be able to see that when you break it open. It'll look slightly powdery or have actually little gritty, shiny bits in it...before you go psychopath about it though, do look up what trichomes are meant to look like so that you don't mistake them for the aforementioned.

All the best.

 

Pickle jars aren't the best choice.

 

get yourself a brand new mason jar.
it will trap all odor, thus releasing a strong scent when opened. but if it were to be in a plastic bag or something, the smell would just be leeching out constantly instead...

you can also look into some purpose built containers, here is one of many examples of stash jars:

 

Your mason jar is working how it should. Its not laced chemically