Trouble on the horizon: Agriculture could be disrupted by changes in rainfall patterns brought on by air pollution.

RODALE NEWS, EMMAUS, PA—Air pollution in China is affecting the amount of rain in the country, according to U.S. Department of Energy research released this month. The new research found that air pollution in the eastern part of China has resulted in much less light rainfall—the type that sinks into the ground and helps crops grow—over the last five decades. "People have long wondered if there was a connection, but this is the first time we've observed it from long-term data," says atmospheric scientist Yun Quian. The research appears in this month's Journal of Geophysical Research-Atmospheres.

THE DETAILS: Analyzing pollution and rainfall data, scientists discovered that light rainfall suitable for agriculture decreased in the eastern part of the country by nearly 25 percent over the last 50 years. In other parts of China, drought has become more prevalent, while heavy downpours that lead to flooding plague other areas. Scientists also found that pollution aerosols created smaller water droplets in the atmosphere, which in turn makes it harder for rain clouds to form. In the most heavily polluted areas, rain fell at significantly lower rates than in the pristine conditions, the study cited.

WHAT IT MEANS: While this study focused on China, which has seen an explosion in population and pollution in the last few decades, the type of pollution that hampers light rain—particulate pollution—occurs in this country, as well. "Air pollution knows no national boundaries. Air pollution from China does impact the US, including the West Coast," says Janice Nolen, assistant vice president of national policy and advocacy for the American Lung Association. "Air pollution produced in the U.S. impacts other countries, too, especially Canada."

Disruptions in natural rain patterns don't just cause agriculture and food production problems, but problems for our health, too. It's impossible to quantify how much China's pollution is affecting our health, but the U.S. is producing the same type of pollution, mainly through coal and wood burning, traffic exhaust (especially dirty diesel exhaust), and ships in our ports. "China’s pollution adds to that, but our biggest threats are domestic," explains Nolen. This sooty pollution can cause coughing, wheezing, an increase in asthma attacks, heart attacks, strokes, lung cancer, and even premature deaths.