Burning toast can certainly create a dense and choking smokescreen, but not all kitchen air pollution can be seen.
 
It seems air pollution in kitchens with gas cookers can be much higher than pollutant levels outdoors in the center of cities and beside busy roads.
  
Researchers from the University of Sheffield in the UK have found nitrogen dioxide (NO2) levels in the kitchen of a city center apartment with a gas stove were three times higher than those measured outside the property.
 
Nitrogen dioxide is a toxic gas that contributes to the appearance of brown haze over many cities.
 
Additionally, average particle concentrations measured by the University’s Faculty of Engineering research team in the kitchens of two flats with gas cookers were higher than the levels determined by the UK Government for outdoor air quality. The particles measured were 2.5 microns in size or less, small enough to penetrate the lungs.
  
Ironically, greening a home could be contributing to concentrating this indoor air pollution by making homes more airtight in order to reduce heating requirements.
  
It should be noted the study dealt with a very small sample – 3 residences – but the findings serve as a reminder our homes are perhaps not the pollution free environment we believe them to be.
  
In addition to pollutants from gas cookers, there can be other toxic nasties such as formaldehyde off-gassing from furnishings and cabinets, benzene from paint and plastics and chemicals and contaminants caught up in carpets. 
 
Aside from adequate ventilation when and where it’s needed and perhaps avoiding bringing some of these materials into our homes in the first place, I’ve mentioned in the past a very natural and effective indoor air filter – plants; which can help make your indoor environment a little healthier as well as adding a nice splash of green.
 
Related:
 
Air Pollution – A Primer