That said, we pay to reduce greenhouse gases and other air pollution with higher energy bills, even if these reductions save us money, and transitions will be complicated. (pathsoflight.us)
However, this research doesn't account for the costs associated with other air pollutants released during fossil fuel combustion. (theguardian.com)
It's only when the drones get much heavier, and present a greater safety risk, that he expects they'll need expensive sensors so they can automatically avoid other air traffic. (newscientist.com)