Giving Compass' Take:

• As levels of NOx emissions in urban areas, primarily due to diesel emissions, fall, we may face exposure to more hazardous ultrafine particles than researchers had previously believed.

• How does air pollution affect human health? Does it differ among areas and people? What can be done to reduce air pollution and carbon emissions?

• Read more about air pollution and how it is affecting your health.


Despite the clear public health benefits from reduced NOx emissions, a reduction in NOx gases does not mean that we have completely removed air pollution. Other airborne health hazards are present, including ultrafine particles.

“We have found a fundamental shortcoming in the models that assess and predict air pollution. Our discovery allows us to improve these models and provide politicians with a stronger foundation for making greener decisions,” says Henrik G. Kjærgaard, a professor in the chemistry department at University of Copenhagen.

He and colleague Kristian Holten Møller, in collaboration with researchers from California Institute of Technology, discovered a special mechanism in the process by which certain molecules create particles in the atmosphere. As VOCs (volatile organic compounds) degrade, these molecules create radicals in both right- and left-handed form—a phenomenon in chemistry known as chirality. The researchers have demonstrated that one of these forms can create particles up to 1,000 times faster than the other.

“Previously, no one knew that right- and left-handedness made a difference in how many airborne particles were created. This is important because ultimately, the amount of particles directly correlates with the number of air pollution-related deaths,” according to Møller, a postdoc in the chemistry department.

Read the full article about emissions cuts by Maria Hornbek at Futurity.