A group of activists say they will know in a few weeks whether the dust covering car hoods and tabletops at homes near the Cemex cement plant in Lyons, Colorado, comes from the facility or other sources.

Members of the Colorado Citizens Campaign, an environmentalist group urging Cemex to curb pollution from its Lyons plant, spent the week collecting dust samples with cotton swabs at homes within a half-mile of the facility.

The group enlisted Denny Larson, director of San Francisco-based Global Community Monitor, to help Cemex’s neighbors collect data about the makeup of the dust around their homes.

Cemex spokeswoman Susana Duarte said she is interested to learn the results but has questions about whether the tests are scientifically sound. “There’s just a lot of dust out there environmentally that’s part of the ground,” she said.

The Lyons plant routinely emits just 25 per cent to 35 per cent of the dust it can discharge under Environmental Protection Agency standards, Duarte said. Meanwhile, plant operators are making preparations to burn as many as 1 million discarded tyres each year to fuel their cement kiln.