Researchers from Tampere University and the University of Helsinki have identified an unexpected chemical process that may drive urban air pollution. Their study, published in Nature Communications, shows that nitric oxide—a pollutant from vehicles and power plants—can promote the formation of aerosol particles, overturning a decades-old assumption in atmospheric science.
The finding challenges the conventional view that nitric oxide primarily suppresses particle formation. Aerosol particles are a key component of smog and have serious health and environmental impacts. This discovery suggests that urban air quality models may need significant revision.
The scientists detailed how nitric oxide interacts with other atmospheric compounds to seed particle growth. While the exact mechanisms remain under investigation, the work highlights a previously overlooked pathway for pollution in cities where NO levels are high.
If validated, these results could reshape how cities manage combustion emissions and assess health risks from air pollution. The study raises fresh questions about the effectiveness of current reduction strategies aimed at nitrogen oxides.
The research team plans to conduct field studies to confirm the lab findings in real urban environments. Further analysis is needed to quantify the effect's contribution to overall particle pollution.