Colton, Grand Terrace, and southwest San Bernardino are neighboring communities in San Bernardino County, located within the South Coast Air Quality Management District. These areas are home to diverse and predominantly Latino populations, with Colton and San Bernardino having particularly high percentages of Hispanic or Latino residents and significant numbers of households speaking Spanish at home. All three cities have younger populations, median household incomes below the California average. Major air pollution concerns stem from heavy freeway and rail traffic, extensive warehouse operations generating thousands of daily diesel truck trips. These pollution sources contribute to elevated rates of asthma and low birth weight, especially in San Bernardino, which ranks among the highest in California for asthma prevalence and low-birth-weight babies.

The district has teamed up with Aclima and the California Air Resources Board (CARB) to launch a community air monitoring project guiding future actions as a part of SMMI. Using Aclima’s advanced sensors, the project collects detailed, block-by-block data on air quality throughout the community. This provides residents with clear information about local pollution and helps guide actions to improve air quality, focusing on the areas and people most affected.

In April of 2025, residents and stakeholders from Colton, Grand Terrace, and southwest San Bernardino met to discuss these challenges and explore solutions for cleaner air and healthier communities.