Nilfisk's HEPA cleaner emitted no more than 400 picograms of allergens per cubic meter of air, a negligible amount.
But many fleets already burn the fuel, which is much cleaner, and emits about one-third less carbon than gasoline.
Avoid using powerful cleaning agents such as bleach or ammonia during pregnancy, and steer clear of abrasive cleaners that emit powerful odors, such as scrubbing powders and bathroom cleansers.
And while California says that its main objective is to obtain cleaner cars that emit fewer smog-forming pollutants, it is also true that hybrids tend to go farther on a gallon of gas than conventional cars and thus emit less carbon dioxide, a big factor in global warming.
In both Europe and America, the commitments made in Kyoto in December to reduce greenhouse-gas emissions will require coal to be replaced with cleaner fuels: gas plants emit 40% less carbon dioxide.Europe is moving the same way.
Burney is examining a similar trade-off between sulfur and black carbon in the United States, as coal-fired electricity plants shift to cleaner natural gas, which emits half as much CO2 as coal per unit of electricity.
Even without climate legislation, coal-based power production is being held somewhat in check by low prices for natural gas, a cleaner fossil fuel that emits roughly half the CO2 as coal when it is burned.
There are the pollutants we bring in through products we buy like furniture and cleaners, and toxins emitted from things we use like kitchen equipment, paints, indoor grills, and even wood burning stoves.
It aimed to reduce power-plant emissions of mercury 70percentt by 2018, through a system that capped total emissions, set the amounts of mercury that power plants could emit and let cleaner plants sell unneeded allowances.
They're cleaner because they don't emit greenhouse gases or soot: the heat and water they generate as a byproduct can be used for cooling and heating the tower.
