The amount of nicotine that smokers typically inhale per cigarette rose by 11% from 1998 to 2005, perpetuating a ”tobacco pandemic” that makes it harder for smokers to quit, a Harvard study said on Thursday. To boost amounts of nicotine inhaled by smokers, cigarette makers intensified the concentration of nicotine in their tobacco and modified cigarette designs.

A Washington-bound United Airlines flight from London made an emergency landing in Boston on Wednesday after a confrontation with a woman suffering from claustrophobia, but there was no apparent terrorist threat, police and security officials said.