Ad: When Ventilation isn’t Enough: The Importance of Filtration in Polluted Locations

By Paul Williams, Domus Ventilation Product Manager

We like to think we’re safe in our homes, but when it comes to air quality, that’s not always the case as levels of air pollutants in the home can be up to five times higher than those outside.  The leading causes of indoor air pollution are:

  • Cleaning products
  • Air fresheners
  • Frying meat
  • Outdoor emissions entering our homes, with NOx and 5 being particularly harmful to human health

The first two can be addressed relatively easily by everyone, such as switching to non-toxic cleaning products, but emissions from external sources are hard to avoid unless we are to keep our doors and windows tightly shut all year round. 

Dispersing Pollutants

Pollutants can, of course, be dispersed through mechanical ventilation systems, with the most effective being Mechanical Ventilation with Heat Recovery (MVHR).  These bring ‘fresh’ air into the home and extract stale air.  However, if those properties are located in areas with high pollution levels, the air being fed into the home is not as ‘fresh’ as we might think, as the standard filters on an MVHR system can only do so much.  Road transport is the biggest source of NOx, so properties located near a busy road are most at risk.

The Dangers Posed by Pollutants

Exposure to NOx is a serious threat to health, with known links to lung disease, heart disease, dementia and strokes.  The greater the concentration of the pollutant over longer periods of exposure make for a worst health outcome. 

The Need for Filtration

MVHR systems are becoming increasingly popular in new builds and are recognised in Building Regulations as the most proficient means of ventilating a dwelling.  But as we can see, in areas of high external pollution they may end up unwittingly contributing to poor indoor air quality.  In these instances, ventilation has to be combined with filtration. 

Domus Ventilation NOX-FILT

Carbon has excellent filtration properties as wide ranging pollutants are attracted to its surface and absorbed.  The Domus Ventilation NOX-FILT utilises a carbon filter cell that prevents up to 99.5% of NO² pollution from entering a home.  A further unit in the range has the added benefit of a PM2.5 pre-filter to maximise the filtration of particulate matter.  These filters work on the supply leg of the ducting of an MVHR system and, with an extremely low profile, readily fit in to restricted building spaces with minimal resistance impact on the ventilation system.  All filters are simple to purchase and replace, with the environmental advantage of the cells being re-used by having carbon matter simply replaced. 

Take Action on Air Pollution

The UK is systematically and persistently breaching air pollution limits. NOx limits alone are being exceeded in 33 out of 43 air quality assessment zones.  Whilst the government’s Clean Air Strategy sets out ambitious targets to reduce NOx and PM2.5 pollution, we can’t afford to simply shut our door against external pollutants and wait it out, hoping for a positive outcome.  We have the technology to deliver fresh, filtered air into our homes; let’s use it.


By Paul Williams, Domus Ventilation Product Manager

Domus Ventilation is a manufacturer of market-leading ventilation systems that save energy and improve indoor air quality.


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