In June the Washington Region was racked by a brutal heat wave, with yesterday marking the 11th consecutive 90+ degree day.

Temperatures reached the 90s or higher on 18 days, tying a record set in 1943.

In the past, such heat levels might have produced a dozen or more Code Red (unhealthy for all) air quality days. Yet, despite record temperatures our region did not experience one Code Red day.

In fact, the region has not had a Code Red day since 2008. This despite stricter ozone standards implemented by the Environmental Protection Agency in March 2008. (For more on ozone standards, click here.)

This past Monday, the region topped out at a smoldering 97 degrees Fahrenheit. Yet the region had Code Green (good) air quality. Last Thursday was the hottest day of the month with the mercury hitting 100 degrees. Yet the air quality was Code Yellow (moderate). (For a calendar view of air quality days, click here.)

And while we’ve had 11 Code Orange (unhealthy for sensitive groups) days so far this year, on five of them only a single monitor (out of 18 across the region) registered Code Orange. On no day did a majority of monitors register Code Orange.

In the 1980s, the region averaged 17 Code Red days per year.
Last decade, the average was less than three.

Remarkably, this progress has been achieved despite the addition of millions of new people, automobiles and vehicle miles traveled.