Suisun City Air Quality Index (AQI)

Loading live AQI data...

Loading historical AQI trends...

Suisun City, California, occupies a unique position within the San Francisco Bay Area’s urban-rural gradient, nestled along the Suisun Marsh, the largest contiguous brackish wetland on the West Coast. Its coordinates (38.2473, -122.0091) place it in Solano County, a region experiencing rapid growth and a complex interplay of agricultural, industrial, and residential land uses. The city’s terrain is predominantly flat, characteristic of the Sacramento-San Joaquin Delta region, with elevations generally below 50 feet above sea level. This low elevation, combined with its proximity to the marsh and the Sacramento River, contributes to a tendency for fog formation, particularly during cooler months. Surrounding Suisun City are extensive agricultural fields, primarily dedicated to row crops and orchards, which can be sources of particulate matter and volatile organic compounds (VOCs) through tilling, pesticide application, and biomass burning. To the west lies the Suisun Marsh, a vital ecological area but also a potential source of biogenic VOCs. Further west, the urban sprawl of the Bay Area gradually encroaches, bringing with it vehicular emissions and industrial activity. The city’s location within the Delta also means it’s susceptible to regional weather patterns, including temperature inversions that can trap pollutants. The prevailing westerly winds, while generally dispersing pollutants, can also carry them from the larger Bay Area metropolitan region, impacting Suisun City’s air quality. The urban character is a blend of historic waterfront areas and newer residential developments, with a relatively limited industrial footprint within the city itself, though nearby industrial zones contribute to regional pollution.

Suisun City’s air quality experiences a distinct seasonal pattern dictated by its climate and regional meteorological influences. The dry season, typically spanning from late spring through early fall, often presents the greatest air quality challenges. During these months, high temperatures and persistent sunshine contribute to photochemical smog formation, where sunlight reacts with pollutants like nitrogen oxides and VOCs to create ozone. Temperature inversions, common during this period, trap cooler air near the ground, preventing pollutants from dispersing vertically. Agricultural activities, such as harvesting and field preparation, release particulate matter into the air, exacerbating the situation. Fall, while transitioning out of the dry season, can still experience elevated particulate matter levels due to agricultural burning, although regulations have significantly reduced this practice. Winter brings cooler temperatures and increased fog frequency, which can temporarily improve air quality by trapping moisture and reducing sunlight intensity. However, fog can also trap pollutants near the ground, leading to localized episodes of poor air quality. Spring sees a gradual improvement as temperatures rise and winds increase, dispersing pollutants. Sensitive groups, including children, the elderly, and individuals with respiratory conditions, should be particularly cautious during the summer months and be aware of potential impacts from elevated ozone levels. Limiting strenuous outdoor activity during peak ozone hours (typically mid-morning to early afternoon) is advisable. During periods of agricultural burning, staying indoors with air filtration can provide relief.