Feature: Reducing pollution from the construction industry 

Air Quality News explores how modern methods of construction can help to reduce air pollution.  

According to the Conservative Party manifesto the UK needs to build 300,000 new homes a year to deal with the ongoing housing crisis, an increase of over 50% compared to 2010 levels. 

Despite the desperate need for new homes, ramping up construction on this scale raises some obvious environmental concerns. Aside from land-use change, material waste and increased carbon emissions, increasingly there are concerns about the impact that the construction industry has on the quality of our air.   

According to the UK’s National Atmospheric Emissions Inventory, the construction industry has contributed to around 25% of the total nitrogen oxide (NOx) and particulate matter (PM2.5) pollution since 1970. 

Transport 

The construction industry contributes to air pollution in several ways but one major source is the transportation of goods and services. Using traditional methods of construction it takes around two years to build a standard family home with an average of 22 different subcontractors needed. 

This, plus the delivery of goods and materials means that there can be upwards of 30 different vehicles visiting a construction site on any one day. When you multiply this by 300,000, it means a lot of moving vehicles, all producing air pollutants.  

One solution for reducing the number of vehicles travelling backwards and forwards from a site is constructing the properties off-site using Modern Methods of Construction (MMC). 

MMC is a process which focuses on off-site construction techniques, such as mass production and factory assembly. MMC can be more sustainable as homes are precision-engineered to create less waste and are built using sustainable materials. This approach also provides benefits by speeding up delivery, reducing labour costs and improving quality. This means MMC can ‘kill two birds with one stone’ by helping us to ramp up our construction output  without contributing to environmental pollution. 

Andrew Shepherd, Managing Director of TopHat Solutions, a leader in the Modern Methods of Construction space explains: ‘Our manufacturing takes place in Derbyshire, and everything is built and created in one location as homes are mechanically moved around the factory. 

‘The houses then arrive at the site 95% complete, meaning the time spent at the construction site is a fraction of what normally happens. The contracting industry is extremely transient meaning people may live in one area but drive multiple hours a day to work in another. We have found that the people working in our factory are much more likely to live nearby and get public transport to work. This means we are contributing to much less transport emissions in the first stage of delivery.’  

Modular houses and Modern Methods of Construction have gained significant interest in the last few years with investment from the likes of Legal & General and Goldmans Sachs boosting confidence in the industry. 

The UK government has also begun to implement policy to shift towards modular housing, with schemes such as the Home Building and Construction Corridor  encouraging market growth and allowing the supply of these structures to be produced.  

However, currently only 15,000 modular homes are built per year, a fraction of the 300,000 needed.  

Machinery  

In areas where off-site construction is not possible, there are still ways that the industry can reduce its contribution to air pollution. According to one estimate, 14% of particulate matter (PM2.5) produced from the construction industry comes from the machinery used.  

James Bellinger, Senior Air Quality Consultant at global design and planning firm ARUP explains that this is because a lot of the tools and machines used at construction sites are powered by diesel generators.  

In a recent literature review, researchers at ARUP highlighted several key areas where developers can reduce air pollution. These include:  

• Having a low or zero emission equipment requirement 
• Planning for the on-site provision of grid electricity 

• Planning sites so they can be built to allow for zero emissions 
• Considering emissions and equipment choices during the design of a project 

Despite clear ways to improve the air pollution output, James explains that the construction industry still has a big issue with communication.  

‘A key area for improvement is actually in the planning stages that are between where a site is designed and before a contractor is appointed to do the work.  

‘Historically, those two stages don’t work that well together and that results in opportunities being missed in the design process. For example, electrical connection could be added to avoid the need for diesel generators but because this communication doesn’t happen we are left with a situation where the contractor is appointed to do the work in a set amount of time and realistically they’re not going to turn up and ask for changes to reduce air pollution because for them, time is money.’ 

It is clear that to meet our housing needs we not only need to ramp up the scale of construction but we also need to shake up how we do things. However, as said by Andrew Shepherd, ‘There is a lot of muscle memory in the industry. 

‘There are lots of senior decision makers that have over 30 years worth of experience in doing things in a certain way, so asking them to do something completely differently is very difficult. To achieve our goals, we all need to invest and support future solutions.’