Statewide data roundup: air quality in review (so far)

Although this year's wildfire season isn't over yet, the recent good air quality allows some time to check in on this summer's air quality. And so far, there have been a few fires in Washington that have caused smoky days, but we mostly haven't observed transport of smoke from neighboring states or Canada. We also haven't (yet) observed strong easterly wind events that contribute to larger smoke events in Western WA. In the plot below, each row is a county in WA, which are organized by region. The colors correspond to the daily air quality index at the most impacted air quality monitor observed in each county on a given day since May 1. Areas experiencing poor air quality were largely closest to active fires (Chelan, Asotin, and Yakima Counties), but poor air quality was also associated with 4th of July fireworks.

Air quality index values by county and day since May 1. Boxes outline events (4th of July) and periods of smoke impacts in Asotin, Chelan, and Yakima Counties.

A closer look at a few of the fires that have caused smoke impacts so far:

Chelan and Okanogan Counties were impacted by the Pioneer Fire near Lake Chelan, which started on June 8. Looking at a few select air quality monitoring sites in Chelan and Okanogan Counties and the number of days of moderate or worse air quality--the worst impacts were closest to the fire in Stehekin, but the Chelan monitor at the southern part of the Lake also experienced a few days of air quality in the Unhealthy for Sensitive Groups and Unhealthy categories:

Number of days in each air quality category for select sites in Chelan and Okanogan Counties since the Pioneer Fire began. Note that good air quality days are not shown. Asterisks indicate temporary monitors.

The Retreat Fire near Naches began on July 23 and caused a few days of poor air quality before smoke production dramatically decreased.

Daily PM2.5 concentrations at monitoring sites in Yakima County while the Retreat Fire was active.

In Asotin County, Clarkston has been impacted mostly by the Cougar Creek Fire (which is now 80% contained and producing minimal smoke), as well as smoke from regional fires in Idaho. Since June, Clarkston has observed 4 days of Unhealthy air quality:

 

Number of days in each AQI category observed at the air quality monitor in Clarkston.

Smoke Outlook: Air quality in the state today is mostly good and moderate, and that will continue through tomorrow. However, hot and dry weather conditions starting Wednesday will increase smoke production and fire danger. We're keeping an eye on the potential for smoke impacts later this week in Southwest WA as smoke from fires in Oregon will drift over the region. As of now, impacts will likely be mostly moderate with the potential for a few hours of USG. Any smoke impacts will likely hang around until westerly flow returns later in the weekend. We'll update the blog with new information later this week.