Evaz, nestled in Fars Province, Iran, occupies a geographically significant position at coordinates 27.7600° N, 54.0067° E. The city’s terrain is characterised by a semi-arid landscape, typical of much of southern Iran, with rolling plains gradually rising towards the Zagros Mountains to the west. This proximity to the mountains influences local wind patterns and can contribute to temperature inversions, trapping pollutants. Evaz isn’t directly adjacent to a major body of water, though the Persian Gulf lies approximately 200km south, exerting a limited influence on humidity. The surrounding region is predominantly agricultural, with date palm groves and wheat fields dominating the landscape. However, increasing industrial activity, particularly related to petrochemicals and cement production in nearby cities like Bandar Abbas and Shiraz, contributes to regional background pollution levels that impact Evaz. The urban-rural gradient is relatively sharp; Evaz itself is a small city with a population under 20,000, surrounded by sparsely populated agricultural land. Dust storms originating from the deserts to the west and southwest are a frequent occurrence, exacerbating particulate matter concentrations. The city’s elevation, around 1,500 meters, plays a role in atmospheric stability and pollutant dispersion.

Evaz experiences a distinct seasonal air quality pattern dictated by its semi-arid climate. Spring (March-May) brings moderate temperatures and occasional dust storms, leading to elevated particulate matter (PM10 and PM2.5) levels. These dust events, originating from western and southwestern deserts, are particularly problematic. Summers (June-August) are intensely hot and dry, with stable atmospheric conditions and reduced wind speeds. While industrial emissions may decrease slightly during peak heat, the lack of dispersion leads to pollutant build-up. Autumn (September-November) often sees improved air quality as temperatures cool and rainfall increases, washing away accumulated pollutants. However, temperature inversions become more frequent, trapping pollutants near the ground. Winter (December-February) is relatively mild but can experience prolonged periods of stagnant air, especially with fog formation, leading to increased concentrations of nitrogen dioxide and sulfur dioxide from domestic heating sources. Sensitive groups – children, the elderly, and those with respiratory conditions – should limit outdoor activity during spring dust storms and winter stagnation events. Months of September and October generally offer the most favourable air quality conditions for outdoor pursuits.