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.