The Washington Department of Ecology (Ecology) defines designated areas as areas expected to have 24-hour PM2.5 design values exceeding Ecology's healthy air goal of 20 µg/m^3. The form of the PM2.5 design value is the 3-year average of the annual 98th percentile 24-hour average concentrations. These areas were identified using a combination of model output from the Air Indicator Report for Public Awareness and Community Tracking (AIRPACT-4) forecast model and measured PM2.5 concentrations at monitoring sites operated by Ecology and its partner agencies. All input datasets cover the time period July 2014 – June 2017, which was the most recent continuous 3-year period available with minimal wildfire influence. Wildfire data were not removed completely from the dataset; rather, data were chosen and filtered to minimize the influence of wildfires due to inconsistent model performance and extreme outliers during wildfire periods.Design values were interpolated using the following steps:Median daily AIRPACT-4 forecast PM2.5 concentrations were extracted at 4km grid cell centroids.The ratio between the measured 98th percentile PM2.5 concentration (as a surrogate for the 24-hour design value) and the nearest grid cell's median daily AIRPACT-4 forecast PM2.5 concentration was calculated for each monitoring site.The ratios were interpolated across the domain at 4km resolution using Empirical Bayesian Kriging.Interpolated ratios were multiplied by median daily AIRPACT-4 forecast PM2.5 concentrations to yield interpolated PM2.5 design values.Grid cells with design values above Ecology's healthy air goal of 20 µg/m^3 were extracted and dissolved into smoothed polygons. Only polygons with ≥3 contiguous grid cells were retained due to model uncertainty in small areas.Polygons were overlaid with city, census-designated place, and urban growth area boundaries from 2020 Census TIGER/Line files. Where polygons intersected with any of the above census-defined boundaries, the largest of the intersecting boundaries defines the designated area.Ecology plans to update the designated areas layer at least every five years in conjunction with its 5-year Ambient Air Monitoring Network Assessment.

Interactive maps from the National Integrated Drought Information System. Drought is one of many factors that can affect the intensity and severity of a fire. Dry, hot, and windy weather combined with dried out (and more flammable) vegetation can increase the potential for large-scale wildfires. Use the interactive map below to explore wildfire, smoke, and air quality data alongside drought and climate conditions. Drought can have significant impacts on water utility operation, including loss of water supply, poor source water quality, increased costs, and reduced revenues. Use the interactive map below to explore water supply data (streamflow, river forecasts, snow water equivalent) alongside drought and climate conditions. Drought can have significant direct and indirect economic impacts on the agricultural sector, reducing the water availability and water quality necessary for productive farms, ranches, and grazing lands. Use the interactive map below to explore agricultural commodities data alongside drought and climate conditions.