/Concerns Raised Over Fresh Air Sources for Low Carbon Homes
– Enviropass highlights potential pollution risks for new low carbon homes
– Mechanical ventilation dependence raises questions about air quality
– Urgent need for integrated planning addressing air quality, carbon emissions, and overheating
Enviropass, known for conducting air quality assessments for planning applications across London and the UK, is voicing concerns regarding the fresh air sources for newly constructed low carbon homes. With these homes designed to be well insulated and airtight, they effectively reduce heat loss and carbon emissions. However, the reliance on mechanical ventilation to bring in outside air, particularly when intakes are located near busy roads, could pose significant challenges for residents’ air quality.
The organization emphasizes that their stance does not oppose the push for net zero emissions. The transition from gas boilers to heat pumps has been pivotal in significantly reducing pollution levels on London’s streets, as gas boilers in commercial buildings represent the largest source of nitrogen oxide emissions in the City of London. The crux of the issue lies in the quality of air being drawn into these sealed buildings.
“It’s a bit like a snorkel,” said Matthew, a Director at Enviropass. “An airtight building breathes through its ventilation intake. Net zero and clean air should work together, but that only happens if someone asks where the air is coming from before the building is designed.”
Enviropass’s assessments frequently reveal substantial variations in pollution levels even within the same development site, with facades facing main roads exhibiting much poorer air quality than those overlooking quieter areas or courtyards. While it’s acknowledged that many mechanical systems come equipped with filters, the location of air intakes remains a critical factor that must be considered during the initial design phase.
There is also an ongoing conflict with policies designed to combat overheating. Urban planners in London are increasingly advocating for buildings to utilize passive cooling strategies such as natural ventilation. However, this approach can be problematic; opening windows in areas with heavy traffic can allow pollution to infiltrate living spaces. Enviropass argues that carbon emissions, overheating concerns, and air quality must be examined collectively rather than in isolation by different stakeholders at various stages of development.
An air quality assessment is a technical document included with a planning application that evaluates whether a proposed development could worsen local air quality and whether future inhabitants will be at risk of exposure to harmful levels of pollution. According to the London Plan, all new developments should achieve at least Air Quality Neutral status, with many councils requiring assessments for sites located within Air Quality Management Areas, which encompass much of the city. These assessments adhere to guidelines established by the Institute of Air Quality Management (IAQM).
“By the time a scheme reaches us, the building is designed and the intake is fixed,” a spokesperson explained. “The positions of the air intakes are the responsibility of the architect and developer at the design stage. They need to consider this from the very beginning.”
With hundreds of thousands of new homes slated for construction in London over the coming years, many adhering to airtight, low carbon standards, Enviropass anticipates the challenges related to air quality will escalate. The organization is urging developers and architects to incorporate local air quality considerations at the early stages of the design process, prior to submitting any planning applications.
