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18 July 2019
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The government’s Clean Air Strategy aims to improve indoor air quality and facilities managers can help to implement it, says Mark Taylor. 

© Getty Images
© Getty Images

01 April 2019 | Mark Taylor 


Pollution shortens lives, which means that air quality is at the top of the environmental agenda and obligates FMs to improve indoor air quality (IAQ) in buildings. 

The priority has been to tackle the biggest causes of pollution. As these major emission sources have decreased, however, the relative contribution of smaller and more diffuse reasons for air pollution – particularly from particulate matter (PM) – has grown. 

In 2017, two airborne pollutants – PM and nitrogen dioxide – cost the NHS and social care in England almost £43 million. The total healthcare cost of air pollution is expected to be £1.6 billion between 2017 and 2025.

The Clean Air Strategy explained  

The Clean Air Strategy sets out the action required from all parts of government and society to cut public exposure to PM pollution, as recommended by the World Health Organisation. 

There will be England-wide powers to control major sources of air pollution as well as local powers to take action in polluted areas. Clean Air Zones will also be created to lower emissions from all sources of air pollution, backed by clear enforcement mechanisms.

The Clean Air Strategy recognises that reducing outside air pollution from traffic and exhaust fumes is only part of the story, with a programme of work across government, industry and society to reduce emissions from a wide range of sources.

Cleaning indoor air

A tight building envelope can also trap indoor pollution sources inside. These sources include: 

  •  Organics from building materials;
  •  Carpet and other furnishings; 
  •  Cleaning materials; 
  •  Air fresheners and paint; 
  •  Adhesives; 
  •  Photocopying machines; and 
  •  Biological contaminants from dirty ventilation systems

There is a fundamental link between OAQ and IAQ because outdoor air penetrates unprotected buildings through supply air ducts, doors, and windows and air leakage. 

The idea of effective ventilation is to mix indoor air with outdoor air to reduce indoor pollutants. In a ventilation system with inefficient filters, particles of varying sizes can enter a building and human bodies.

Effective filters

Filters provide air cleaning capabilities and form a first line of defence against air pollution. Air filters can remove harmful particulates before they reach people. 

Typical particulates found in air include:

  •  Coarse particles, often 10 microns (μm) or bigger (1µm = 1/1,000th of a millimetre). Examples include visible coarse dust, sand, leaves, hairs and other large organic particles. 
  •  PM10 – airborne particles  =/< 10µm in diameter including coarser fine dust and organic particles. 
  •  PM2.5 – airborne particles =/< 2.5µm in diameter such as pollen, spores and other organic particles. 
  •  PM1 – airborne particles  =/< 1µm in diameter, including dust, combustion particles such as diesel fumes, bacteria and viruses.  

The human body can filter coarse particles. PM10 particles can be stopped at the throat and PM2.5 particles by the lungs and alveoli. 

PM1, however, penetrate the bloodstream and can contribute to serious illness. At worst, it can contribute to diseases such as heart attacks, lung cancer, dementia, emphysema and oedema. 

ISO 16890 Guidance

It is critical that filters are categorised on the basis of how efficiently they perform against PM10, PM2.5 and PM1 particle sizes and this is the central purpose of the new air filtration standard – ISO 16890.

ISO 16890 defines testing procedures and a classification system for air filters used in general ventilation equipment. It provides the first opportunity for global harmonisation as it replaces two existing ‘local’ standards – ASHRAE 52.2 in the US and EN779:2012 in Europe. Both standards coexisted in Asia and the Middle East.

For the first time, ISO 16890 tells FMs specifically what a filter will do. For example, a typical air filter of a class that is going to make a difference to IAQ is defined in the new standard as ‘ePM1 60% minimum’ where ‘e’ stands for the removal efficiency of the filter, PM1 is the range of particles (=/< 1µm in size), and 60 per cent is the percentage of particles the filter will remove.  

Mark Taylor is sales director at Camfil