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Zahedan, the capital of Sistan and Baluchestan Province in southeastern Iran, occupies a strategic position in the arid Dasht-e Lut desert basin near the borders with Afghanistan and Pakistan, approximately 1,352 meters above sea level. This high-desert city lies within the vast Sistan Plain, characterized by flat, sandy terrain with sparse vegetation, surrounded by the Makran Mountains to the south and the rugged hills of western Afghanistan to the north. Its location in a rain-shadow region results in minimal precipitation, while the absence of major rivers or permanent water bodies exacerbates dust accumulation. Zahedan serves as a crucial transportation hub along the Quetta-Zahedan-Mashhad corridor, with urban sprawl blending into semi-arid rural landscapes dominated by subsistence agriculture and pastoralism. The city's air quality is profoundly influenced by its geography: frequent dust storms originating from the surrounding deserts, particularly the Registan Desert in Afghanistan, transport fine particulate matter into the urban area. Additionally, local pollution sources include vehicular emissions from cross-border trade routes, small-scale industries, and biomass burning for heating and cooking. The urban-rural gradient sees higher pollution concentrations in the city center due to traffic congestion and construction activities, while outlying areas contend with agricultural residue burning and wind-blown dust. This combination of natural and anthropogenic factors creates a persistent baseline of airborne particulates, worsened by the region's climatic aridity and topographic enclosure.

Zahedan's air quality follows a distinct seasonal pattern shaped by its desert climate and regional wind systems. In winter (December-February), cold temperatures and frequent temperature inversions trap pollutants near the ground, particularly from residential heating using wood and low-quality fuels, leading to elevated particulate levels; sensitive groups like asthmatics and the elderly should limit outdoor exertion during morning hours when inversions are strongest. Spring (March-May) brings the notorious '120-day wind' (Levar) from the northwest, which can dramatically improve air quality by dispersing local emissions but also triggers intense dust storms from Afghanistan's deserts, causing sudden spikes in PM10 and PM2.5; outdoor activities are best scheduled after dust events subside, typically in late spring. Summer (June-August) sees scorching heat exceeding 40°C, which increases ozone formation from vehicular emissions, though strong afternoon winds often provide temporary relief; however, drought conditions elevate dust resuspension, making early mornings preferable for exercise. Autumn (September-November) offers the most favorable air quality, with milder temperatures, reduced dust activity, and fewer inversions, making it ideal for outdoor pursuits; nonetheless, occasional biomass burning from agricultural clearance can cause short-term pollution episodes. Year-round, vulnerable populations should monitor local advisories for dust storms and use protective masks during high-wind events.