Two Harvard professors say they are developing an experiment that would release a small quantity of sulfate particles into the atmosphere to see how well they combine with water vapor to reflect some of the sun’s rays back into space. Physicist David G. Keith and atmospheric chemist James G. Anderson Â are proposing that the experiment be done using a balloon launched from a NASA facility in New Mexico. The researchers said they would inject “micro” amounts of sulfate particles into the atmosphere and that there was no chance they would affect climate, either locally or globally. The men vehemently denied a report in the Guardian that they were planning to inject tens or hundreds of pounds of sulfate particles into the atmosphere. Keith, a leading scientist in the controversial field of geoengineering the planet’s climate to counter global warming, said the experiment was designed to measure the impact of releases of sulfate particles, including the possibility that they would interact with chlorine and harm the earth’s ozone layer. Keith said outdoor geoengineering experiments should be conducted only with public funds and after a thorough public review.