Kehen, nestled in the regency of Bangli, Bali, Indonesia, occupies a geographically significant position within the island’s central highlands. Located at -8.5589, 115.2869, and with a modest population of 11,779, Kehen’s urban character is distinctly rural, retaining a strong connection to traditional Balinese life. The surrounding landscape is dominated by volcanic terrain, part of the larger Mount Batur volcanic complex, contributing to a relatively high elevation, influencing local climate and air circulation patterns. The town sits within a valley, flanked by gently sloping hills covered in rice paddies and interspersed with small villages, creating a gradual urban–rural gradient. Kehen’s proximity to Mount Batur, an active volcano, presents a unique challenge; while volcanic ash can temporarily degrade air quality, the prevailing winds generally carry it away from the populated areas. The town is not directly adjacent to a major body of water, though irrigation canals fed by mountain springs are vital for agriculture. The nearest significant industrial activity is located further south, around Denpasar and its surrounding areas, minimizing direct industrial pollution impact. However, agricultural practices, particularly the burning of rice straw after harvest, can contribute to localized air pollution events, especially during drier periods. The valley location can also trap pollutants, particularly during periods of low wind speed, leading to stagnant air conditions. The overall topography and surrounding agricultural zones are key factors shaping Kehen’s air quality profile.

Kehen’s tropical climate dictates a wet and dry season cycle, profoundly impacting its air quality. The dry season, typically spanning from May to October, often sees a slight increase in particulate matter due to agricultural burning. Farmers clearing fields after the rice harvest frequently employ controlled burns, releasing smoke and ash into the atmosphere. While these burns are often localized, the valley’s topography can trap the smoke, leading to temporary reductions in visibility and potential respiratory irritation. The wet season, from November to April, brings increased rainfall, which naturally helps to cleanse the air by washing away pollutants. However, periods of prolonged rainfall can also lead to increased humidity, which can exacerbate respiratory conditions for sensitive individuals. Fog, common during the wet season, can trap pollutants close to the ground, creating localized pockets of poor air quality. Temperature inversions, though less frequent than in temperate climates, can occasionally occur, particularly during cooler nights, trapping pollutants near the surface. Wind patterns are generally consistent, with prevailing winds blowing from the east, which usually disperses pollutants. During the dry season, particularly August and September, outdoor activities should be approached with caution, especially for children, the elderly, and those with pre-existing respiratory conditions. The wet season generally offers improved air quality, but individuals with asthma or allergies should remain vigilant regarding humidity and potential mold growth. Maintaining indoor air quality through ventilation and air purification can be beneficial year-round.