'Big experiment' this July 4th shows personal fireworks are the main cause of air pollution | KNKX

'Big experiment' this July 4th shows personal fireworks are the main cause of air pollution

Jul 10, 2020

People in the Pacific Northwest sometimes jokingly call the sixth month here "Juneuary," because of the persistently gloomy weather we often face in June. Now an abundance of offshore flow — marine air coming in off the cool Pacific Ocean — has KNKX weather expert Cliff Mass calling July "Julember."

“The first week of July was the coolest since 2002. Lots of clouds coming in and below normal temperatures,” Mass said. “I do hope that later in the month we'll start to warm up.”

But what really caught his attention this week — and that of many local clean air agencies — was the aftermath of Fourth of July celebrations, which always produce a lot of small particle pollution, because of the fireworks.

These small particles can enter people’s lungs and harm human health, especially in people with sensitivities such as asthma or heart disease.

This year, due to the coronavirus epidemic, all the major communal fireworks displays were canceled. Mass called this a “big experiment” to see what difference that would make in the local air quality.

The big question is how much do community fireworks, the big ones like in Seattle, contribute? And how much do personal fireworks contribute — you know, that people shoot off all around the region?” Mass said.

This year, we were able to see what personal fireworks alone due to air quality, he says. The data are in. And the outcome was remarkable.  

“Measurements at the Puget Sound Clean Air Agency sites around the region showed that this was a much worse year than last year, maybe 25 percent worse,” he said. “The amount of particles in the atmosphere were substantially increased not only over last year, but over the last several years before that. So this was not a good year.”

A temperature inversion led to stagnant air throughout the region this year, which can slow down the rate at which pollution disperses.

Still, Mass says it’s clear that personal fireworks produce the lion’s share of the small particle pollution that degrades air quality late on July 4 and early on July 5.  

Obviously, we'd want more years to be absolutely sure. But my basic conclusion is that personal fireworks are the main cause of air pollution,” he said. “Community fireworks might contribute a little bit. But it's the personal fireworks that are the main source of such pollution.”  

Listen to the full conversation above. 

The weekly KNKX feature "Weather with Cliff Mass" airs every Friday at 9 a.m. immediately following BirdNote, and repeats twice on Friday afternoons during All Things Considered. The feature is hosted by KNKX’s Environment reporter Bellamy Pailthorp. Cliff Mass is a University of Washington Professor of Atmospheric Sciences and a renowned Seattle weather prognosticator.  You can also subscribe to a podcast of “Weather with Cliff Mass” shows on AppleSpotify and Google.