Urban greening brings to mind rooftop gardens, tree lined streets, and vines climbing the walls of high-rise buildings. At least for me, it’s always been something aesthetic, rather than acoustic. But this fourth blog in our Acoustics in the Sun series, covers acoustic perception via Timothy Van Renterghem from Ghent University in his paper Audio-visual interactions in environmental noise perception and the link to urban greening.

Noise perception

This paper covered a lot, and is worth reading. It introduced many terms I had never heard before, but formalised concepts that I use every day when explaining how sound masking works. For example, when we experience noise as less loud, that’s called information masking. There’s a high probability I’ll never use these terms again, but it’s good to know they exist!

Most of the paper’s findings covered how humans perceive noise. We experience our environment in a multi-sensorial fashion. This is why people believe that a line of trees between their house and a major highway reduces the noise from that highway. It does not. But they feel like it does. Often that is is enough to make living in that environment more pleasant.

Urban greening and annoyance

In fact, there is a strong correlation between improved vegetation and reduced annoyance and stress. The paper explored several theories as to why adding greenery into our lives would reduce our annoyance at noise. It also covered the virtual reality studies used to simulate urban greening.

To have the greatest impact on our annoyance at noise, biodiversity and colour are more important than a perfectly manicured garden. A variety of colours of trees had the biggest positive impact.

What does this mean for urbanites?

Thankfully, we don’t have to live in a forest to get the benefits of greenery. The “sweet spot” is around 30-35% greenery compared to infrastructure. Also, taking “micro-restorative episodes” (ie, glancing out the window from time to time), can be enough to reduce stress and annoyance for many people. Though, as the paper points out, much of this is subjective and dependent upon the individual’s personal connection to nature.

There is still more work to be done, and it’s good to know that the work continues, especially as so many of us live in units or apartments, then work in office blocks.

You can find the full paper here.