Nearly Half of Days in 2021 Were in the “Moderate” Range
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 2021, nearly half of the days in the year (48%) were in the “moderate” range, which was higher than the percentage of days reported in 2020 (42%). The second most common air quality status in 2021 was “unhealthy for sensitive groups” (20%), followed by “unhealthy” (17%). In addition, 3% of days were “very unhealthy” and one day (0.3%) was “hazardous.” Only one in nine days (or 12% of days) were considered “good” in 2021. However, the median Air Quality Index value improved in 2021 compared to 2020 (87 and 93, respectively). Both values are in the high end of 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 |
MEDIAN AIR QUALITY INDEX VALUE IMPROVES IN 2021
Air Quality Index in San Bernardino County, 2013-2022
* Data for 2022 are preliminary. The percentages were calculated on 332 days with AQI data in 2022, whereas the remainder of the years shown were calculated with 365 (or 366) days with AQI data. The 2022 data were retrieved January 22, 2023 and subject to change.
Source: U.S. Environmental Protection Agency, Air Data (www.epa.gov/outdoor-air-quality-data)
| Year | Good | Moderate | Unhealthy for Sensitive Groups | Unhealthy | Very Unhealthy | Hazardous | Median AQI Value |
|---|---|---|---|---|---|---|---|
| 2013 | 18% | 45% | 23% | 13% | 1% | 0.0% | 84 |
| 2014 | 10% | 55% | 22% | 12% | 0% | 0.0% | 80 |
| 2015 | 12% | 52% | 24% | 10% | 1% | 0.0% | 83 |
| 2016 | 8% | 55% | 21% | 13% | 3% | 0.0% | 83 |
| 2017 | 8% | 51% | 20% | 14% | 6% | 0.0% | 84 |
| 2018 | 12% | 46% | 26% | 14% | 2% | 0.0% | 88 |
| 2019 | 15% | 48% | 19% | 15% | 2% | 0.0% | 80 |
| 2020 | 14% | 42% | 21% | 17% | 3% | 0.3% | 93 |
| 2021 | 12% | 48% | 20% | 17% | 3% | 0.3% | 87 |
| 2022 | 26% | 38% | 18% | 16% | 2% | 0.0% | 77 |
MEDIAN AIR QUALITY INDEX VALUE IMPROVES IN 2021
Air Quality Index in San Bernardino County, 2013-2022
GEOGRAPHIC COMPARISON
Within peer regions, there is variation in the number of days each region experiences in the six Air Quality Index categories – from “good” to “hazardous.” However, the median Air Quality Index value, which takes into account all daily AQI readings in a given year, was higher in San Bernardino County in 2021 than all regions compared except Phoenix.
SAN BERNARDINO AIR QUALITY POORER THAN PEERS, EXCEPT PHOENIX
Regional Comparison of the Air Quality Index, 2021
Note: These data are based on hourly monitor data to assess air quality, resulting in more days of unhealthy air than data that is used by air quality management districts for regulatory compliance, which uses 24-hour monitor values.
Source: U.S. Environmental Protection Agency, Air Data (www.epa.gov/outdoor-air-quality-data)
| Air Quality Index by Regions | Good | Moderate | Unhealthy for Sensitive Groups | Unhealthy | Very Unhealthy | Hazardous |
|---|---|---|---|---|---|---|
| Phoenix Metro | 11 | 117 | 103 | 61 | 73 | 0 |
| San Bernardino County | 42 | 177 | 73 | 61 | 11 | 1 |
| Riverside County | 42 | 187 | 89 | 44 | 2 | 1 |
| Los Angeles County | 39 | 229 | 70 | 26 | 1 | 0 |
| San Diego County | 98 | 251 | 16 | 0 | 0 | 0 |
| Las Vegas Metro | 154 | 212 | 31 | 3 | 0 | 0 |
| Orange County | 201 | 146 | 18 | 0 | 0 | 0 |
| Miami Metro | 257 | 105 | 3 | 0 | 0 | 0 |