Global levels of the hydrocarbons ethane and propane in the atmosphere have been underestimated by more than 50%, according to a new study by a team of scientists from Europe and the US. When ethane and propane—the most abundant non-methane hydrocarbons (NMHC) in the atmosphere—mix with nitrogen oxides from vehicles and power plants they form tropospheric ozone—a key component of smog and directly linked to increases in mortality. This new study shows that global fossil fuel emissions of these hydrocarbons have been underestimated and are a factor of 2-3 times higher than previously thought. Accounting for these enhanced ethane and propane emissions results in simulated surface ozone concentrations that are 5–13% higher than previously assumed in some polluted regions in Asia. The team used the OsloCTM3 model to simulate the pre-industrial (year 1750) and current (year 2011) distributions of atmospheric ethane and propane. The OsloCTM3 simulations are driven with […]