Giving Compass' Take:

• Hannah Hickey reports that air quality emissions regulations to limit nitrogen oxides will have long-term impacts, but will not produce quick results. 

• How can funders help to guide quick action so that long-term results can come sooner? 

• Learn why air pollution is bad for education. 

Declining levels of nitrogen oxides due to tighter emissions standards will ultimately lead to cleaner air—but it might take longer than first thought.

As air quality improves, the invisible chemistry happening in the air around us is changing. Skies should clear up as emissions drop, but recent results suggested that declining nitrogen oxides can create an environment where airborne carbon-containing compounds more easily convert into small particles that harm human health.

Regulators can now breathe easier, researchers say. A new study provides a fuller picture of the relationship between nitrogen oxides—the tailpipe-generated particles at the center of the Volkswagen scandal, also known as NOx—and PM2.5, the microscopic particles that can lodge in lungs.

A key finding is how the concentration of NOx changes the chemistry of the hydrocarbon vapors that transform into the particles less than 2.5 microns across, or about 3 percent the width of a human hair—to affect the formation of PM2.5 found in smog.

“We found that there are two different regimes of PM2.5 formation,” says first author Joel Thornton, a professor of atmospheric sciences at the University of Washington. “One where adding NOx enhances PM2.5, and one where adding NOx suppresses PM2.5.”

Read the full article about air quality emissions regulations by Hannah Hickey at Futurity.