Clean Indoor Air for Healthy Living – New Air Filter Standards


Breathing air is a fact of life. We all do it. Unfortunately the air that comes into our bodies often carries unwelcome pollution. This air pollution comes in the form of a mix of toxic particles and acidic gases.

Urban traffic air pollution has been a rising public concern especially since the recent VW scandal demonstrated car manufacturers have been more interested in dodging emission tests than providing clean running diesel engines.

The government is also slow to take action to remedy the situation having been responsible for previously promoting use of polluting diesel engines. If you live in a polluted urban area or close to a source of air pollution such as an arterial road, industrial plant or power station then you will be exposed to this invisible health hazard.

These airborne contaminants can penetrate in your lungs and can enter your bloodstream causing damage to health and diseases. The recent study from Lancaster University shows that ultrafine combustion particles generated from high temperature fuel combustion have been found in heavy concentrations in the brains of people suffering from early onset of Alzheimer disease and dementia.

This is a concern because it indicates that traffic air pollution can not only damage our health physically but also mentally. A real and current problem; what is the solution?

What measures can we as individuals take to protect ourselves and minimise our exposure to outdoor sourced air pollution? Well it is not all bad news there are things that can be done and actions taken.

For a start we spend typically about 90% of our time indoors so our direct exposure to outdoors air is reduced as a result. The buildings we occupy at work and at home to some extent act as a haven against this threat to our health.

There are also air monitoring and measuring devices that are relatively affordable coming onto the market. As Lord Kelvin the distinguished scientist once stated. ‘To measure is to know.’ It is now possible to use newly available and affordable devices to measure pollutants of concern and compare them with published World Health Organisation limits. Some of these measuring devices also have the capability to control air purifiers and air cleaning devices.

The two outdoor urban air pollutants most commonly identified as health hazards are PM1 combustion particulate and nitrogen dioxide. The World Health Organisation and Royal College of Physicians recent report ‘Every breath you take’ go into detail about the health implications. PM1 is a mass measurement of particulate matter one micron diameter and below in size range. A micron is one thousandth of a millimetre.This is very small as any particle below 10 micron dia. cannot be seen unaided by the human eye. A human hair is typically 70 micron dia.

Once the seriousness of the problem of polluted indoor air has been established then action can be taken. Although a relatively airtight building will offer some protection against urban traffic pollution there will be penetration into the building by opening windows, doors, passage of people and ventilation air systems. Typically the penetration for PM1 and nitrogen dioxide will be in the range 30% to 70%.

The only effective solution currently available to reduce this level is to use mechanical air filtration.

There are two new ISO World standards to test air filters recently published that offer filter testing and classifications to aid effective selection of HVAC air filters.

ISO 16890:2016 is running alongside EN779:2012 in the UK during the transition period until June 2018 at which point EN779:2012 will be withdrawn by BSI.

ISO 16890:2016 enables selection of filters to remove PM1 particulates to a high level of efficiency. In the new classification system ePM1 85% would equate to a good F9 filter but is more useful and informative notation to the end user because it actually says what the filter will achieve. Filtration efficiency ‘e’ will remove PM1 size range particles to an efficiency of 85%.

For the removal of molecular gas contaminants such as nitrogen dioxide the new World filter test standard is ISO 10121:2013. A good nitrogen dioxide removal test reading for a single supply air pass would be 80% – 90% initial efficiency.

These high filter removal efficiencies (80% – 90%) are necessary when air pollution levels are routinely higher than WHO limits by a factor of four or five times in UK city centres.

This is fine for filters in large air handling unit systems in central London but what about me at home? Is there another option available apart from keeping windows and doors shut on bad air pollution days?

The answer is that a good recirculation Air purifier unit positioned close to the person needing clean air will give the healthy solution needed. A well designed unit can provide E11 – H13 Hepa particulate filtration with molecular gas filtration for the removal of nitrogen dioxide, but also the commonly encountered indoor sourced air pollutants such as volatile organic compounds (VOC’s) and aldehydes such as Formaldehyde. These units are especially valued by asthmatics and allergy sufferers.

This blog was written by Peter Dyment, Technical Manager at Camfil Ltd. To find out more information about IAQ please check out BSRIA’s website.


Indoor Air Quality a health and wealth issue for us all

Peter Dyment, Camfil

Peter Dyment, Air Quality and Energy Consultant – Camfil Ltd.

Indoor Air Quality is a slightly vague concept to most people. When asked they tend to adopt the Goldilocks principle. Not too hot, not too cold, not too damp, not too dry. This reflects the fact that for many generations now we have had the means to control our home and work environment with comparatively little discomfort and little attention being required.

However the golden age of low cost energy and apparently limitless resources seems to be coming to an end. Sustainability is the order of the day. We are all waking up to the real value of energy and the environmental cost involved when linked to our population growth. One cost is the realisation that in cities and near busy roads in the UK there is no longer such a thing as clean fresh air.

We all breathe air to live and if it is polluted or carries airborne diseases we can fall ill as a result. Airborne hazards such as Carbon monoxide or longer term indoor threats like Radon release are sometimes a problem but the toxic fine combustion particles mainly from traffic emissions and some power stations are the major health risk to the public at large.

Technology to the rescue, if we can’t control the weather and have trouble on a national level controlling air pollution then the solution is we can at least try is to control Indoor Air Quality. Ventilation is needed into buildings to replenish used Oxygen from the air and displace the Carbon Dioxide we all exhale.

The British and European standard that gives us the Indoor Air design parameters is the rather long titled BS EN 15251:2007 Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics’. This also adds the parameters of light and sound levels which can enhance or blight an inside environment.

There has been concern expressed that in the urgent quest for energy savings in large building HVAC systems engineers have been turning off or turning down plant to save energy at the expense of poor building Indoor Air Quality.

A useful European study called Healthvent has recently produced a report that attributes the levels of Burden of Disease for Indoor Air on indoor sourced pollutants and outdoor sourced pollutants respectively. The ratio shows that approximately twice as much BOD can be shown to come from outdoor sourced pollution.

To save building energy losses it has been usual practice to make building envelopes as well sealed as possible as shown by BSRIA testing. This also has the added benefit of helping stop ingress of outside sourced air pollution into the building. Healthvent identified three strategies to reduce outdoor sourced air pollution coming into the building.
1. Optimal dilution using ventilation
2. Effective Air Filtration to reduce PM2.5 by 50%
3. Source control of pollution

Effective Air Filtration was shown to be the easiest measure to implement and give the best reduction of incoming pollution with minimum effort.

Anybody can now access through the internet information on air pollution levels in their locality. There is a national monitoring network run by DEFRA and the local authorities. The Kings College website even allows Londoners to enter their post code and directly get a map of historic readings on their doorstep(example below)

pm2 5 map bsria

The recent study by Rob Beelen and his team on PM2.5, published in The Lancet, estimates that for every increase of 5 microgrammes per cubic metre (5 µg/m3) in annual exposure to fine-particle air pollution (PM2·5), the risk of dying from natural causes rises by 7%. A simple calculation indicates a routine increase in the mortality rate in central London of over 20% as a result of high levels of PM2.5 mainly from traffic emissions.

Natural causes of death in this instance can be respiratory and cardio vascular disease and recent analysis of data by the Campaign for clean air in London has highlighted that air pollution is one of the exposure categories causing all the top four male death categories and four of the top five female death categories in London i.e. Ischaemic heart diseases; Malignant neoplasm of trachea, bronchus and lung; Chronic lower respiratory diseases; and Cerebrovascular diseases.

It can be seen that the evidence is now compelling and action is now required both at a national level and on a personal level to ensure the air we all breathe is clean and healthy.  Some measures such as effective air filtration and air sealed buildings can mitigate exposure to this air pollution in the short term.

Peter Dyment is Air Quality and Energy Consultant at Camfil Ltd (BSRIA Member). Camfil Ltd also has two other excellent sites for readers: 

BSRIA is running an event looking at living with the problems of Indoor Air Quality.  To find out more and to book onto the event got the BSRIA website.

%d bloggers like this: