1. That from nearly 10 years of observations from NASA’s Aura satellite.
2. Nitrogen dioxide levels have decreased thanks to technological improvements in cars and power plants.
3. Comparing 2005 to 2011, the biggest gains are in large eastern cities.
TAG: These are important developments for those with respiratory difficulties.
EXTRA: Nitrogen dioxide levels down by...(see percentages below for select cities).
Los Angeles: 40%