Waterfall Sounds and Sulfur Scent Shape a Uniquely Relaxing Soundscape

Yosua W. Tedja – yosuatedja@gmail.com
Lucky Tsaih, Veerin Udomsopakit, Khaing Thinzar, Sanh T. Diep, Shiang-I Juan
Department of Architecture, National Taiwan University of Science and Technology, Taipei, Taiwan

Popular version of 4aNS7 – Beyond Odor Intensity: Assessing Sensory Congruence in the Restorative Soundscape of Beitou Thermal Valley
Presented at the 190th ASA Meeting
Read the abstract at https://eppro01.ativ.me/web/planner.php?id=ASASPRING2026

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

While a strong sulfur scent might seem like an unlikely ingredient for relaxation, it doesn’t ruin the soundscape at northern Taiwan’s Beitou Thermal Valley. In fact, visitors find the experience uniquely restorative because the distinctive smell perfectly matches the steaming vapor, milky green hot springs, and the steady rush of falling water.

Tourists gather on walkways overlooking a steaming hot spring surrounded by lush greenery and rocky terrain.

Figure 1. Visitors gather at Beitou Thermal Valley as sulfur-rich steam rises from the geothermal pool. Image courtesy of the authors.

Video 1. Beitou Thermal Valley scenery and on-site visitor comments regarding the sulfur smell. Video courtesy of the authors.

Beitou Thermal Valley is one of Taiwan’s most famous hot spring landscapes. Its distinctive scent comes mainly from hydrogen sulfide, a naturally occurring gas. In an ordinary place, this smell might feel unpleasant. But in this geothermal valley, it becomes part of the site’s identity.

Steam rising over clear turquoise water near a rocky shoreline with scattered leaves and twigs.

Figure 2. A close-up of Beitou Thermal Valley’s steaming, milky green geothermal water. The sulfur-rich hot spring water releases the distinctive smell that shapes visitors’ sensory experience at the site. Image courtesy of the authors.

To examine this experience, visitors were surveyed near the waterfall area locally known as Witch’s Rock Waterfall, as shown in Figure 3. In this open-air setting, the sulfur smell and waterfall sound occur together. The sound level was about 61.6 dBA, roughly similar to a busy restaurant, as heard in Video 2.

Small waterfall cascading over mossy rocks surrounded by hanging vines and lush greenery beside an informational wooden sign.

Figure 3. The Witch’s Rock Waterfall at Beitou Thermal Valley. Image courtesy of the authors.

Video 2. The sound environment at the waterfall zone measured about 62 decibels. It is not quiet, but not overwhelming either, roughly the volume of a busy restaurant. Video courtesy of the authors.

The findings were clear: a stronger sulfur scent did not equate to a worse sound experience. Most visitors still evaluated the soundscape positively, proving that sensory harmony matters most. When the distinct smell, ambient sound, rising steam, and visual landscape felt connected, the environment became highly restorative.

For public-space design, this offers a valuable lesson: comfort does not always come from removing every strong sensation. At Beitou Thermal Valley, the sulfur odor is not a flaw; it is an essential part of the place. This study proves that nature’s best remedy doesn’t always rely on complete silence and floral breezes. Sometimes, true relaxation comes from steam, a sulfur scent, and the steady roar of falling water, perfectly aligned to tell the same sensory story.