A long-term high-resolution air quality reanalysis with a public-facing air quality dashboard over the Contiguous United States (CONUS)

We show that our dataset captures regional hourly, seasonal, and interannual variability in meteorology very well across the CONUS. The correlation coefficient between the observed and simulated surface ozone and PM2.5 concentrations for different regions defined by the Environmental Protection Agency (EPA) across the CONUS are 0.77–0.91 and 0.49–0.79, respectively. The mean bias and root-mean-square error for modeled ozone are 3.7–6.8 and 7–9 ppbv, respectively, while the corresponding values for PM2.5 are −0.9–5.6 and 3.0–8.3 µg m−3, respectively.

We estimate that the annual CONUS-averaged maximum daily 8 h average (MDA8) ozone and PM2.5 trends are −0.30 ppb yr−1 and −0.24 µg m−3 yr−1, respectively. Wintertime MDA8 ozone shows an increasing but statistically insignificant trend at several sites. We also found a decreasing trend in the 95th percentile of MDA8 ozone but an increasing trend in the 5th percentile.

Most of the sites in the Pacific Northwest show an increasing but statistically insignificant trend during summer. An ArcGIS air quality dashboard has been developed to enable easy visualization and interpretation of county-level air quality measures and trends by stakeholders, and a Python-based Streamlit application has been developed to allow the download of the air quality data in simplified text and graphic formats.