Eldoret, situated in Kenya's Uasin Gishu County at coordinates 0.5167°N, 35.2833°E, occupies a strategic position in East Africa's Rift Valley region, approximately 2,100 meters above sea level. This elevated plateau location significantly influences its air quality dynamics. The city lies within a fertile agricultural zone known for maize, wheat, and dairy farming, with surrounding rural landscapes transitioning into urban areas, creating a distinct urban-rural gradient. Eldoret's terrain is characterized by rolling hills and valleys, with the Sosiani River flowing through the city, though its modest size provides limited air-cleansing effects. Positioned along the Trans-African Highway corridor connecting Kenya to Uganda, Eldoret experiences transportation-related emissions from freight and passenger vehicles. The city's growth as an educational and commercial hub has led to increasing urbanization, with residential areas mixing with light industrial zones on the periphery. Its location in the Rift Valley basin can occasionally trap pollutants under stable atmospheric conditions, particularly during cooler periods. The surrounding agricultural activities contribute particulate matter during planting and harvesting seasons, while the city's elevation generally promotes better air dispersion than lower-lying regions. Eldoret's geographic isolation from major industrial centers like Nairobi provides some protection from heavy industrial pollution, but local sources including vehicle emissions, biomass burning for cooking and heating, and occasional dust from unpaved roads collectively shape its air quality profile.

Eldoret's equatorial highland climate creates distinct seasonal air quality patterns influenced by rainfall, temperature, and wind regimes. During the long rainy season from March to May, increased precipitation effectively washes particulate matter from the atmosphere, resulting in the year's cleanest air conditions. This period offers optimal conditions for outdoor activities, with sensitive groups experiencing minimal respiratory irritation. The short rainy season from October to December similarly provides good air quality, though slightly less consistent than the long rains. June through September represents the cool, dry season when temperatures drop significantly at this elevation, leading to increased biomass burning for heating in both urban and surrounding rural areas. This period typically sees elevated particulate matter levels, particularly in morning hours when temperature inversions can trap smoke near the surface. January and February constitute the warm, dry season, characterized by increased dust from unpaved roads and agricultural preparation activities, though generally better air quality than the cool dry period due to stronger daytime convection. Sensitive individuals including those with asthma, children, and the elderly should limit outdoor exertion during early mornings in the cool dry season when pollution concentrations peak. The city's elevation generally prevents severe pollution episodes, but seasonal biomass burning remains the primary concern for air quality degradation.