Stagnant Smoke Suffocates Seattle

By Jackie Stowe

fires on hill
                                                                    Wildfire seen in Omak, Okanogan County. Source: The Seattle Times

While the warmth and smell of a fire may be enjoyable to many, the health effects from smoke are anything but a good time. Wood smoke, from sources such as wood stoves, fireplaces, recreational burning, and wildfires, is made up of a mixture of gases such as carbon monoxide and fine particles that are small enough to infiltrate and irritate the respiratory system. Short-term effects such as a cough, headache, or runny nose are bothersome, but new studies show that exposure to these fine particles can even increase risk of cardiac arrest and other heart problems.  


Where Does Seattle’s Smoke Come From?

In these graphs, the EPA shows that Washington’s main sources of particulate matter pollution, or PM2.5, comes from wood burning and wildfires. Wildfires are most prominent in the summer, while wintertime pollution comes from heating sources such as fireplaces and wood stoves.

What Weather Events Affect Pollution From Wood Fires?

While wind can aggravate a fire, it’s also a necessary component to clear up a hazy day. Wind is needed to disperse smoke into a larger area, and rain is also helpful in washing away the fine particles of smoke.   When a day with little to no precipitation encounters a stable lower atmosphere and light winds, air stagnation can occur.

Poor air quality conditions in Western Washington are affected by the presence of high pressure fronts, which are usually accompanied by clear skies, no rain, and no wind. These fronts can cause temperature inversions that trap cool air under a blanket of warm air, impacting air quality by limiting the amount of mixing of air, which pushes smoke down to the surface under the warm layer. The winter months are especially prone to inversions due to the low temperatures and more cold air that sinks to the surface, which intensifies the high pressure front. If the sun and wind are too weak to break the inversion, residents living in the valleys can notice especially bothersome effects of smoke due to their location—pollution can be trapped in regions of low elevations surrounded by mountains, far from breeze of the ocean to help mix out the pollutants. Burn bans are put into effect around the region during this smoke-heavy time, not in fear of a wildfire, but to decrease amounts of new smoke from wood stoves and fireplaces to avoid exacerbating conditions.

Meteorologist Dustin Bonk notes that wind can also play a part in pollution by transporting smoke from wildfires long distances. Similar to how a highway transports cars across a nation, the jet stream relocates smoke from fires in British Columbia across the United States, from Washington to New England.

The Future of Smoky Days in Seattle

Changes in temperature and precipitation exacerbate climate conditions such as fires, heat waves, floods, and droughts, and in turn increase the amount of people exposed to particle pollution and ozone, which are both affected by these climate changes. Particle pollution from wood smoke can even play a part in climate change by affecting the reflectivity of the clouds, indirectly influencing the lifetime and precipitation of the clouds as well.        

How do wood burning and forest fires affect the earth’s climate? NASA’s Forrest Hall discusses how long-term carbon is primarily stored in ground moss, root production, and duff (soil containing decayed organic matter). These substances are very flammable when dry, and after catching on fire they release a thick, polluted smoke. Not only does this smoke contain carbon dioxide and irritate one’s senses, but fine particles called aerosols are also emitted. These tiny particles are so bright that they actually reflect light back into space, limiting the amount of sun and warmth that can reach the earth’s surface. In contrast, smoke also releases dark aerosols such as soot that absorb light, warming the earth.

The Intergovernmental Panel on Climate Change has projected that “declining air quality in cities” will become more prominent due to climate change. As Australia experienced intense and devastating fires in 2009, killing or injuring nearly 200 people, Seattle also experienced the influence of high temperatures and low precipitation that enraged deadly fires in the past summer.

Who is at Risk?

In a study done by Daniel Horton and his colleagues at Stanford University, research shows that the amount of air stagnation will increase dramatically by 2099. His study found that 55% of the global population will experience more stagnation; when population is factored in, locations such as Mexico, India, and the western United States will be most impacted. This means that in less than 100 years, there’s a good chance that polluted days in Seattle will become more intense with less air circulating and dispersing smoke from wildfires and other sources of wood smoke.

It’s recommended that everyone protects themselves from the toxic pollutants of smoke, but sensitive groups, such as the children, the elderly, pregnant women, and those with pre-existing heart and respiratory conditions, are the most susceptible to the effects of smoke. Children and infants should be monitored closely for a few reasons: their respiratory systems are still developing, they typically spend more time outdoors, and they breathe more air, and therefore more pollution. Someone with a condition such as asthma or congestive heart failure tend to experience the effects of pollution at lower levels than healthy people, and can suffer from more intense symptoms like chest pain, fatigue, and an inability to breathe deeply.

To prevent sickness, it’s important to keep up-to-date on air quality reports, use heavy-duty masks, and decrease the usage of indoor pollution irritants such as candles and gas stoves. If you or someone you know is suffering from the symptoms of smoke pollution, get medical help immediately.


Jackie Stowe is a junior at UW Bothell majoring in Society, Ethics, and Human Behavior. She grew up in Redmond, Washington. She cares about the air we breathe because "every living thing on this planet deserves to flourish without being impacted by environmental issues."