AIR QUALITY TRENDS ARE MIXED FROM YEAR-TO-YEAR, BUT SOME OVERALL IMPROVEMENT
Poor air quality can aggravate the symptoms of heart and lung ailments, including asthma. It can also cause irritation and illness among the healthy population. Long-term exposure increases the risks of lung cancer, cardiovascular disease, and many other health conditions. Poor air quality can also put children’s lung development at risk. This indicator uses the Air Quality Index (AQI) to measure air quality in San Bernardino County, neighboring California counties, and peer regions outside of California.
TREND
The most common air quality status for San Bernardino County is the “moderate” range. In 2023, more than half of the days in the year (54%) were in the “moderate” range. Since 2015, the percentage of days in the moderate range has been generally decreasing. These are being replaced with more days in the “good” range, but also more in the “unhealthy” range. The median AQI value, where a higher value represents poorer air quality, improved in 2023 compared to the 10-year high in 2020 (71 and 93, respectively). Both values are in the “moderate” range.
Air Quality Index Key
| Index Value | Name | Advisory |
|---|---|---|
| 0 to 50 | Good | None |
| 51 to 100 | Moderate | Unusually sensitive individuals should consider limiting prolonged outdoor exertion |
| 101 to 150 | Unhealthy for Sensitive Groups | Children, active adults and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion |
| 151 to 200 | Unhealthy | Children, active adults and people with respiratory disease, such as asthma, should avoid prolonged outdoor exertion; everyone else should limit prolonged outdoor exertion |
| 201 to 300 | Very Unhealthy | Children, active adults and people with respiratory disease, such as asthma, should avoid prolonged outdoor exertion; everyone else should limit outdoor exertion |
| 301 to 500 | Hazardous | Everyone should avoid all physical activity outdoors |
MIXED AIR QUALITY RATINGS OVER TIME, BUT MEDIAN AQI IS GENERALLY IMPROVING
Percentage of Days When Air Quality Index Was Good, Moderate, Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy or Hazardous in San Bernardino County, 2015-2024
GEOGRAPHIC COMPARISON
Within peer regions, there is variation in the number of days each region experiences in the six AQI categories – from “good” to “hazardous.” However, the median AQI value, which takes into account all daily AQI readings in a given year, was higher in San Bernardino County in 2023 than all regions compared except Phoenix and Riverside County.
SAN BERNARDINO AIR QUALITY POORER THAN PEERS, EXCEPT PHOENIX
Regional Comparison of the Number of Days in 2023 when the Air Quality Index was Good, Moderate, Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, or Hazardous