Boulder scientists have been sending one ton of instruments up and down a 1,000-foot-tall tower east of Erie for weeks to measure the presence of a destructive chemical compound that forms on the Front Range during winter nights.
Scientists from the National Oceanic and Atmospheric Administration were caught by surprise in February 2008 when they accidentally discovered the presence of high concentrations of nitryl chloride in Boulder's night air. The researchers were packing up instruments built to measure the nitryl chloride concentrations on the coast -- where chlorine, a necessary building block of the chemical compound, is more abundant thanks to sea salts in the air -- when they flipped on the machines to test them.
At first, they thought the reading was wrong, but eventually, they confirmed that land-locked Boulder does have pollutant concentrations similar to those found at the beach.
Understanding nitryl chloride is important because the compound interacts with other air pollutants and greenhouse gases, such as methane and ozone.
"If we really want to understand ozone on a regional scale, we need to understand what is going on with this chlorine chemistry," said NOAA scientist Steve Brown.
During winter nights, scientists believe that nitrogen oxide pollutants -- released from tail pipes and coal-burning power plants, among other sources -- react with chlorine compounds found on the surface of particles suspended in the air. The reaction creates nitryl chloride, which quickly breaks down when the sun rises, freeing super-reactive chlorine atoms.
The chlorine atoms then spark a chain reaction, stealing hydrogen atoms from "volatile organic compounds" in the atmosphere, which in turn react with oxygen, affecting ozone formation.
And while the Front Range is nowhere near the ocean and its bountiful, chlorine-containing sea salt, the researchers -- including NOAA scientists Jim Roberts and Ann Middlebrook -- think the local sources of chlorine may include the salts spread on Colorado's snowy roads.
The tower in Erie has provided the research team, which includes scientists from across the country, a unique opportunity to measure the atmospheric chemicals, including nitryl chloride, that are present at different heights in the winter, when the atmosphere is not as thoroughly mixed.
"At night, the air on the ground is not necessarily the same as the air above," Middlebrook said.
The researchers plan to continue the study through mid-March, which means at least one of them will have to continue staying at the tower each night.
"We do it for the science," said Roberts, whose turn it was to stay at the tower Tuesday night. "The data make it worth it."
Contact Camera Staff Writer Laura Snider at 303-473-1327 or email@example.com.