A contributing hazard may be ubiquitous use of PVC and similar materials that produce toxic fumes. You do not want to breathe that even if it doesn't suffocate

A contributing hazard may be ubiquitous use of PVC and similar materials that produce toxic fumes. You do not want to breathe that even if it doesn't suffocate you immediately. Smoke from wood and most "natural" materials - you'll usually be fine after a few days, if you manage not to suffocate.