Soot absorbs heat and has a warming effect; sulfate particles reflect radiation and have a small cooling effect.

According to our analysis, a majority of the benefits is associated with sulfate particles, indicating that alternative sulfate toxicities would strongly influence our findings.

For example, our useful efforts to reduce sulfur emissions may have actually increased warming, because sulfate particles reflect sunlight, bouncing it back into space.

Thus, sulfate particles that are relatively harmless by themselves can enhance the injurious effects of ozone.

Blurring of Scenic Vistas At about 2.5 microns, airborne sulfate particles are so small that they cannot be seen through a standard microscope.

Studies in the last three years have demonstrated that sulfate particles produced by the burning of fossil fuels have this effect.

University of Washington scientists report that injecting sulfate particles into the stratosphere will not fully offset climate change.

Sulfur dioxide gas, when converted to sulfate particles in the atmosphere, has long been the primary cause of Eastern haze.

Some of the scattering can also be from sulfate particles.

The sulfate particles or sulfuric acid droplets in the atmosphere are about 0.1 to 1.0 micrometer (a millionth of a meter) in diameter.