Air Quality

More Unhealthy Days of Air in 2017

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.

How is San Bernardino County Doing?

Air quality was poorer in 2017:

  • There were 186 days in the “moderate” range (or 51% of days) in 2017, an increase from 10 years ago when there were 136 days in the moderate range.
  • Meanwhile, there were fewer days of “good” air in 2017 (31) compared to 2008 (68).
  • After several years of declining counts of “unhealthy” and “very unhealthy” days, 2017 marked another year of increases for both levels of air quality.
  • However, the median AQI value shows that air quality has improved substantially from over 30 years ago. In 1986, the median AQI value was 133 (in the “unhealthy for sensitive groups” range) compared to 84 in 2017 (in the “moderate” range).
  • Compared to air quality in neighboring and peer regions, San Bernardino County had poorer median air quality in 2017 than all regions compared, except Riverside County and Phoenix Metro.

Air Quality Index

San Bernardino County, 2008-2017
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Air Quality Index (365 Days Total)

Regional Comparison, 2017
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Note: The regions are sorted from top to bottom according the median air quality index value in each region, from highest to lowest. 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 (