I bounced off Interim Domain, N&T was good but this one is off to a stronger start. Despite my mild skepticism about all these conveniently airtight buildings.
Interim Domain was good but my god it was so boring. Dev is good at writing but the setting is the issue. It's essentially a slice of life disguised as post apocalyptic. I agree Toxicity got a much stronger start than N&T and i'm enjoying it so far. N&T beginning chapters were bland and meandering.
As for the air tight buildings, i'm kinda thinking chem fog is like haze. I'm no scientist but we used to get pretty bad haze here from neighboring countries burning their land for agriculture. It doesn't get into the buildings despite slightly open windows. Smell is there unless you fully close windows but there was no need to tape gaps in doors etc. The in house PSI is still much lower than outside.
If anything i'd pick on the MC's survival skills. From the top of my head, i'd stock up on duct tapes and ropes, they're extremely useful, self explanatory on their applications.
Find some utility knife, swiss army knife.
Make a makeshift weapon like a spear for defense using everyday household items like brooms, mops or metal poles or stuff you find in warehouses.
Create a homemade gas mask using scraps of cloth, duct tape, big plastic bottle for the lens & structure, small tin cans filled with activated charcoal or simple cloth filters. You can literally craft a homemade MOPP 4 gear.
Also stock up on medical supplies like sterile gauze, bandages & splints, antibiotics, antihistamines, painkillers, superglue to close wounds, epipen, powder, medical equipment like shears, scapels, tweezers.
I can go on and on. Point is, you don't need to be military or scientist background or a survival enthusiast, you just need common sense. The crisis is technically easy mode and they're in an area abundant with utility resources though not so much food.
Everything above is easily available in the offices and especially in a College/University. For medical stuff, schools definitely have an infirmary.
And lastly, again, the crisis is literally easy mode. As someone who has been in the army, i'm positive the military would have cleared a small town within the first week. Maybe dev intends to escalate it into something bigger, which i hope what happens because this crisis shouldn't take so long to get under control.