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Iwaki, situated on the eastern coast of Fukushima Prefecture in Japan's Tōhoku region, occupies a distinctive geographic position that significantly influences its air quality patterns. The city straddles the Pacific Ocean coastline to the east while being backed by the Abukuma Highlands to the west, creating a varied terrain that ranges from coastal plains to forested hills with elevations up to approximately 500 meters. This topography channels prevailing winds from the ocean, which typically help disperse pollutants, though the surrounding mountains can occasionally trap air masses. Iwaki lies within Japan's industrial belt, with its economy historically tied to coal mining and now diversified into manufacturing, petrochemicals, and energy production, including the nearby Fukushima Daiichi nuclear plant—though post-2011 decommissioning has reduced industrial emissions. The urban-rural gradient is pronounced, with dense urban cores like Taira district transitioning to agricultural zones producing rice and vegetables, and further out to forested areas. Proximity to the Pacific ensures moderate humidity and marine influences, but the city's location downwind of industrial facilities in the Kanto and Tōhoku regions means it can receive transported pollutants. The combination of industrial activity, vehicle emissions in urban areas, and occasional agricultural burning creates a mixed pollution profile, with geography playing a key role in both dispersion and accumulation of airborne particulates.

Iwaki's air quality follows a distinct seasonal rhythm shaped by its coastal climate and regional meteorology. In winter (December to February), cold air from Siberia brings dry conditions and occasional temperature inversions, particularly in valleys, trapping pollutants like PM2.5 from heating and industrial sources, making January and February the peak pollution months—sensitive groups should limit outdoor exertion during calm, cold mornings. Spring (March to May) sees improving conditions as warming temperatures and increased wind from the Pacific disperse pollutants, though pollen from cedar and cypress forests can aggravate allergies, with April being favourable for outdoor activities. Summer (June to August) benefits from the rainy season (June to July) and typhoons, which wash out particulates, but high humidity and heat can lead to ozone formation on sunny days, so midday outdoor exercise is best avoided. Autumn (September to November) offers the cleanest air, with stable weather and brisk winds from the north sweeping away pollutants, making October ideal for hiking in the Abukuma Highlands. Throughout the year, fog from the ocean can occasionally reduce visibility but doesn't significantly worsen pollution. Sensitive individuals, such as those with respiratory conditions, should monitor local advisories, especially in winter, and use air purifiers indoors during stagnant periods.