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Tarui is nestled within the fertile Nōbi Plain in Gifu Prefecture, serving as a quintessential example of a Japanese small-town urban-rural gradient. The town's geography is profoundly defined by the Ibi River, which meanders through the landscape, creating a lush, alluvial environment that supports extensive rice cultivation. This low-lying, flat terrain is situated between the rugged mountains of the interior and the coastal influence of Ise Bay. Because Tarui lies in a broad basin-like plain, it is susceptible to atmospheric stagnation, where pollutants from regional industrial belts—particularly those emanating from the nearby Chūkyō metropolitan area—can accumulate. The town's character is a blend of quiet residential clusters and sprawling agricultural zones, which minimizes dense urban heat island effects but introduces specific seasonal pollutants. The proximity to the Ibi River introduces a moderating humidity factor, yet the surrounding topography often traps surface-level air during high-pressure systems. As a transitional zone, Tarui experiences a mixture of rural fresh air and the drifting anthropogenic emissions from the arterial roads connecting Gifu and Nagoya. The elevation is minimal, meaning there are few natural barriers to prevent the lateral movement of smog during stagnant weather patterns. Consequently, the air quality is a delicate balance between the purifying influence of the riverine greenery and the regional atmospheric loads typical of the Nōbi Plain's unique geography, making the town a sensitive indicator of Gifu’s overall environmental health.

Air quality in Tarui follows a distinct seasonal rhythm dictated by the meteorological patterns of central Japan. Spring is often the most challenging period for sensitive groups, as the arrival of warmer winds brings an influx of yellow dust from the Asian continent and an intense surge of cedar and cypress pollen, which can exacerbate respiratory distress. As the region transitions into summer, the intense solar radiation and high humidity of the Pacific monsoon trigger the formation of ground-level ozone. During these peak heat months, stagnant air can lead to ozone spikes, making mid-afternoon outdoor activities risky for children and the elderly. Autumn typically offers the cleanest air of the year, characterized by stable high-pressure systems and crisp, clearing winds that sweep pollutants out of the Nōbi Plain. However, winter introduces a different set of challenges. The region is prone to temperature inversions, where a layer of warm air traps cooler, polluted air near the ground. This phenomenon, combined with increased emissions from residential heating and occasional agricultural burning, can lead to a buildup of fine particulate matter during cold, windless stretches in January and February. For those with asthma or COPD, the winter inversions and spring pollen peaks represent the most critical windows for health monitoring. To maintain wellness, residents are encouraged to limit heavy exertion during humid summer afternoons and the stagnant mornings of mid-winter, favoring the refreshing, clear atmosphere of the autumnal transition.