Related by context. Frequent words. (Click for all words.) 64 confined spaces 46 stairwells 45 ventilated 45 cigarette smoke 43 enclosed 43 claustrophobia 43 toxic fumes 43 flammable materials 42 claustrophobic 42 exhaust fumes 42 passageways 42 inhale 42 toxic gases 42 fumes 42 indoors 41 ventilation 40 carbon monoxide 40 stairways 39 secondhand smoke 38 doorways 38 flammable 38 combustibles 38 environments 38 staircases 38 outdoors 38 air conditioned 38 campfires 38 nitrogen dioxide 38 ventilating 38 combustible materials 37 Carbon monoxide 37 banning smoking 37 spaces 37 smoke 37 air ducts 37 inhaling 37 lavatories 37 smoking 37 fireplaces 36 Smoking 36 indoor 36 wood burning stoves 36 vents 35 ductwork 35 particulates 35 odors 35 respiratory tract 35 bathrooms 35 highly flammable 35 workplaces 35 Ventilation 35 ventilate 35 physical exertion 35 suffocation 34 combustion 34 chimneys 34 ducts 34 defecate 34 germs 34 lounges 34 diesel exhaust 34 flammable liquids 33 smoky 33 dust mites 33 cramped 33 space heaters 33 allergens 33 VOCs 33 asthmatics 33 respiratory symptoms 33 garages 33 patios 33 asbestos fibers 33 inhaled 33 soundproof 33 exhaust pipes 33 passenger compartment 33 vapors 33 barbecue grills 33 smokefree 33 emit 32 gymnasiums 32 balconies 32 compartments 32 dust particles 32 air pollution 32 phobias 32 volatile organic compounds 32 flue 32 respiratory illnesses 32 hazardous substances 32 carbon monoxide poisoning 32 passive smoking 32 inhalation 32 airless 32 drafty 32 outdoor 32 wood stoves 32 hazards 32 gases 32 washrooms