How Does Wildfire Smoke Travel?

by Kieran Berryman November 28, 2024

Wildfires are a common occurrence in today’s world. Whether caused by something natural or unnatural, they continually threaten the well-being of people all across the world. But what effects do wildfires cause? Of course, there are immediate physical threats if you are in the area of a wildfire. Fire is fast, hot, and creates thick smoke filled with toxic gasses, which can make getting to a safe place very difficult¹. But there are more dangers than just the immediate threats. Wildfire smoke can travel far distances, affecting air quality over a much larger area than just directly adjacent to the fire. But what does that mean for you?

Defining Wildfires

When we talk about wildfires, what are we actually talking about? Fires exist and are used intentionally all across the world. However, unintentional fires also exist across the world. That is what a wildfire is; “an unplanned fire that burns in a natural area such as a forest, grassland, or prairie²."

The greatest risk with wildfires is that they’re unknown, unpredictable, and can happen anytime. Unfortunately, some of the conditions that lead to wildfires also facilitate their spread. Chiefly, “high winds increase the likelihood that a wildfire will spread³." Heavy but dry winds help small-scale fires (even those that might have started out contained) escalate, potentially turning into larger-scale events. However, high winds can also “move smoke into communities far from a wildfire⁴." This means that even if you aren’t immediately threatened by a fire, its smoke could still be affecting your air quality.

Where Does Wildfire Smoke Go?

It’s mentioned above that wildfire smoke can travel much farther than you might think, beyond the reach of a fire’s immediate threats. But where does that smoke go, how does it get there, and what does it mean for you?

Which Way Does it Move?

There are many factors that determine where wildfire smoke gets dispersed. But, primarily, “the fate of smoke from a wildland fire depends in large part on the airflow carrying it away from a fire.” Put simply, this means that wildfire smoke will primarily travel with the strongest wind direction. Ultimately, “the buoyancy of smoke and ambient atmospheric conditions determine how high and how quickly the smoke rises, and thus where it travels⁵."

How Does it Move?

At surface level, winds may not be as strong because there is a lot of friction from external sources. Higher up in the atmosphere, however, many of those sources don’t exist. It follows, then, that smoke doesn’t primarily move at surface level. A majority of its movement happens higher up. “The intense heat generated by an active wildfire drives smoke high into the air where it remains until it cools and begins to descend⁴." When smoke is high in the air like this, it can be subjected to the previously mentioned heavy wind, which is when it is moved from its original location. This results in the smoke dispersing over a much larger area.

What Does that Mean for You?

Research on wildfire smoke exposure is still developing to determine the effects of long-term exposure, but the short-term effects are well known. Exposure over a period of a few days can cause respiratory and cardiovascular issues. Additionally, a study of wildland firefighters found that exposure over the course of a few weeks resulted in reduced lung function⁶. Long story short, you probably don’t want to breathe in large amounts of wildfire smoke for very long.

How to Monitor Wildfire Smoke

Tracking wildfire smoke can help you make informed decisions about your health and take action to safeguard your air. There are a number of ways you can track wildfire smoke:

The US EPA’s Fire and Smoke map exists for the purpose of tracking the effects of smoke on air quality.
The PurpleAir Map shows air quality readings from all public and online PurpleAir sensors. These readings can be used to track smoke. We recommend using the US EPA conversion if you’re doing this.
If neither of the options above can provide you with readings in your area, you can purchase PurpleAir sensors to set up at your home. These provide highly relevant readings directly where you are.

Sources

Note: This article was originally published 09/28/2022 and updated 11/28/2024.