Add a new item to the list of dangers from hurricanes: air pollution.
High winds, flash flooding, and storm surges typically do the most damage during tropical cyclones. But a team of researchers has now discovered that, given the right set of weather conditions, storm winds can also cloud the skies with harmful dust.
Led by Guor-Chen Fang of Huangkuang University in Taiwan, a team of researchers monitored the number of particles floating in the air when typhoons Sinlaku, Hagupit and Jangmi swept through the area in September 2008.
The storms formed during the early part of the region's dry season, when rivers run low and large swaths of silt and sediment are exposed to the air. As winds picked up about 48 hours before two of the storms hit Taiwan, dust counts increased dramatically. Mixed in among the haze were particles ranging from coarse grit down to fine grains 2.5 microns in diameter; about 1/30 the width of a human hair.
When inhaled, such particles can lodge deep in people's lungs, causing coughing, wheezing, or triggering asthma attacks.
"Ongoing global climate change will likely increase the intensity and frequency of extreme weather," the team wrote in an article published recently in the journal Atmospheric Environment. "It has become necessary to understand the influence of typhoons on air quality."
Randall Cerveny of Arizona State University in Tempe said that air pollution from hurricanes is unlikely to be a major concern, given the cornucopia of dangers the storms bring.
"You have so many other problems with typhoons and hurricanes — wind damage, flooding, power outages — that they're probably going to overwhelm any effects from an increase in air pollution," he said.
Still, Cerveny said that the team's work was useful in that it examined a previously unknown side effects of tropical cyclones.
As the effects of global warming alter rainfall patterns and beef up storms around the world, air pollution events like those in Taiwan could become more common in other regions.
"In general, we haven't studied the juxtaposition of different types of weather, like a dry season with a typhoon," Cerveny said. "Getting detailed observations like the ones in this paper will help us understand how the effects of climate change are showing up around the world."