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Exposure to domestic smoke


Domestic smoke may be responsible for high levels of personal exposure.  Why domestic smoke sources are important and why they differ from industrial and power generation sources is that they have a strong localised variation at ground level.  The health impact depends upon the amount of pollutants you inhale and the amount of pollutants you inhale depends upon the concentration of those pollutants.

Most of the assessments of pollutant concentrations such as PM10 particles has been based upon ambient measurements i.e. in places not close to sources.  This basis has been often used as a benchmark with which to compare air pollution levels of various communities and their associated health impacts.  It is a fine basis to use if there is little variation within each community.  However, the nature of domestic smoke sourced pollution is that breathing zones concentration are highly variable and they may not contribute much to ambient levels.  Concentrations due to mobile sources vary but do contribute to ambient levels because of the widespread occurrence of roads.  It is recognised that levels close to busy roads are higher than otherwise.  Environmental tobacco smoke is a highly localised phenomenon which does produce dangerous levels close to source and in confined spaces with limited smoke dispersal.  ETS does not contribute to ambient levels but is recognised as a significant health impact which has inspired Smoking Bans in all confined and partially public places in the UK.  When assessing the importance of domestic solid fuel smoke, it is important to pay heed to breathing zone concentrations, what those concentrations are and what determines their value and what make them vary from one community to another.

The nearby presence of a domestic fire is not a simple indicator of a high breathing zone pollution level.  The following describes some factors which may vary concentrations:

Factors which determine emission concentrations from a domestic solid fuel appliance are:
  • the type of wood or coal used
  • the moisture content of the solid fuel
  • the size of the solid fuel pieces
  • whether a stove or open fireplace is used
  • the design of the stove or fireplace
  • the design for smoke removal
  • the efficiency of the air inlet design
  • the ability of the room draught to supply the required oxygen
  • the burning temperature
  • the stage of burning ( emissions at initial lighting differ from later stages)
  • how burning is managed
  • whether additional material is burnt (paper; plastic wrappings etc)
    •
Attributes of your local area affect your personal exposure levels by:
  • the amount of fuel burnt per stove/fireplace each day
  • the height and design of chimney stacks
  • your proximity to neighbouring chimneys
  • the number of smoky chimneys per unit area where you live
  • the air tightness of your house during times of burning
  • wind speed and direction affecting dispersal and plume formation
  • dry or wet weather affecting dispersal
  • winter temperature inversion effects holding pollutants close to ground
  • dispersal obstructions local to you such as street trees and high walls
  •  local topography (whether you live in a high, open aspect or a local low lying area)
    •


Review of knowledge of exposure to smoke from domestic sources:
The following is still being written and will be completed as soon as possible
Indoor air in developing countries; pollution from cooking with heat source of biomass fuel



Poorly ventilated coal fires in Xuan Wei Province, China




Indoor air in developed countries




Christchurch, New Zealand street monitoring of pollutants 


Personal exposure scensarios due to various fuel types