IN2AIR: Indoor Environmental Quality

Why Indoor Air Quality Matters

Air pollution (both outdoors and indoors) is a leading cause of premature death and ill heath worldwide; it disproportionately affects the young (it can damage growing lungs and stunt growth), older people (who may spend significant periods at home) and those with weakened immune systems or with certain pre-existing medical conditions (e.g. chronic obstructive pulmonary disease [COPD] and asthma). 


Given we spend a great deal of our time indoors, indoor air quality is central to our health and wellbeing


Main Indoor Pollutants

  • Particulate matter (PM) inc. settled dust
  • Trace elements (such as lead and arsenic)
  • Carbon Monoxide and Dioxide (CO/CO2)
  • Biological agents (inc. mould and bacteria)
  • Nitrogen Dioxide (NO2)
  • Sulphur Dioxide (SO2)
  • Volatile Organic Compounds (VOCs) e.g. Formaldehyde (CH2O)
  • Radon

Indoor Pollution Sources

  • Outside sources (such as dusts brought inside on clothes, footwear, pets or by the wind)
  • Fuel burning appliances (e.g. cookers)
  • Open fires
  • Household products such as air fresheners, cleaning products, solvents, paints
  • Building materials and home furnishings
  • Candles and incense
  • Home office equipment (e.g. printers)
  • People (e.g. smoking) and pets
  • Excess moisture

Different sizes of particles are produced by different activities. For
example, dusting produces larger particles and smoke contains smaller
particles. Cooking (especially frying) produces small particles bound
together by moisture to make larger particles. The smaller the particle
the further into the lungs it is able to travel when breathed in and the
greater the opportunity for it to impact our health.

pm10 plot

It is normal for levels of particulate matter (PM) to change throughout the
day in response to activities like cooking (as can be seen in the example
below), but also dusting, vacuuming, shaking cushions or blankets,
using cleaning sprays, deodorants or air fresheners, or opening doors
and windows.

What can you do to improve air quality at home?


Here are some simple steps you can take to improve air quality in your home from

NICE (National Institute for Health and Care Excellence)



For more information and advice on indoor air quality please visit: