07.02.2017 Author: Blog Admin

Putting Indoor Air Quality At The Top Of The Agenda Outside to Inside – the impact of external air pollution

In early 2017, we have seen a multitude of news stories highlighting the fact that air quality, or lack of it, is becoming an increasingly serious problem. In late January, it was reported that London’s ‘filthy air’ had prompted a high pollution alert for the city, and Londoners were told to avoid strenuous physical activity. The alert is part of a new system set up by London Mayor Sadiq Khan and triggers warning signs at bus stops, road signs and tube stations around the city.

This latest spike in toxic air, the highest level recorded since April 2011, was attributed to an unusual mix of calm, cold and settled weather, which meant that the air was not able to disperse pollutants. However, the problem is far from temporary. With childhood asthma on the increase, the spotlight is turning firmly on the factors affecting air quality, including traffic toxins and nitrogen dioxide (NO₂ or NOx). A recent DEFRA report showed that NOx in particular was responsible for up to 23,500 premature deaths a year. This is due to a number of factors, from traffic fumes, the increasing use of diesel, and a rising number of cars per household. There is also lack of space, leading to the redevelopment of brownfield sites, and planning restrictions now mean that houses are being built closer to each other, close to busy roads and in more densely populated areas. All these factors add up and lead to an increase in toxic air around where we live, work and go to school.

So should we just stay indoors

The thing is, we open our doors and windows during the day and night and have air moving around our homes naturally and from installed ventilation systems.  We need replacement air to keep homes fresh  – but with pollution levels increasing, the freshness of that air can’t be guaranteed. In urban areas especially, high levels of pollution have a considerable impact on IAQ as it enters homes.

IAQ in urban developments is a real concern for many Local Authorities, as up to 3,000 schools and thousands of homes - both existing and planned - are located in areas where the air breaches the pollution standards set by the World Health Organisation (WHO) and many exceeding the targets of 44mpg set out in the EU Clean Air for Europe (CAFE) directive.  Many authorities now are Air Quality Management Areas as well.  As a result, increased planning requirements are being introduced across urban parts of the UK to ensure that residential dwellings meet these standards and provide healthy levels of IAQ for occupants. Because of the increasing level of outdoor pollution, it’s crucial more than ever that that effective ventilation systems are installed in homes to help eliminate the growing health implications of poor indoor air quality. After all, we spend up to 70% of our time indoors.

How do we meet these challenges to deliver good and consistent levels of Indoor Air Quality?

Indoor Air Quality requirements and planning restrictions are inextricabily linked with ventilation – the movement of air in and out of the building.  Ventilation is currently regulated by airflow volumes and energy efficiency targets through Building Regulations and SAP.  Given the IAQ issues, there is now another layer to ventilation specification by way of filtration.  And excellent, high grade filtration at that, specifically targeting NO₂.  The result of planning restrictions and increasing demand for homes has called for the introduction of high grade filters to be used in conjunction with balanced whole house systems such as Mechanical Ventilation with Heat Recovery (MVHR).

These filters offer additional protection to the incoming air from ground to usually third level – where the hazardous gases are at their most concentrated levels and which are harmful to health. 

Do we really want people to breathe the city in their home?

It isn’t just a case of adding in the filter to the system. The priority is always ensuring the airflow performance is achieved.  The unit, ducting and additional filters work together to deliver the performance – alongside design and good installation and commissioning. Adding a filter can add resistance and needs to be designed into the system.  If ventilation isn’t working effectively issues such as mould, condensation and overheating can start to occur and results in complaints and increased costs.

For those interested in learning more about NOx, how the issue affects them and the solutions we offer at Zehnder Group UK, download our datasheet on our newly launched NOx filters.