A study by an Iowa State University researcher says a decline in U-S wind speeds could have major implications for human health and agriculture. Professor Gene Takle says his study shows wind speeds in the country have declined by 15 to 30% over the last 30 years.

Takle says if the trend continues, it could mean an increase in air pollution. Takle says cities with high levels of air pollution do so when the winds are calm, and he says if the number of calm periods increase, there will be more human impact due to air pollution.

Takle is a professor of agronomy and geological and atmospheric sciences. He says there are also implications for plants as well as humans. Takle says when wind speeds decline, there’s more heat build up during the day, and that is not good for the crops, especially when the temperatures get about 95 degrees.

Takle says plants are like people when it comes to stale air. “The crops like to have a little ventilation, so if there’s heat build up, that’s ongoing to put stress on the crops,” Takle says.

Takle says it’s too early to say if the slower winds speeds might also have implications for the wind energy industry. He says wind speeds measurements closer to the ground are more susceptible to increased friction from buildings and tall trees than they are at the level of wind turbines. Takle made his comments Monday on Iowa Public Radio.