SAN FRANCISCO: Health-conscious Californians may mostly oppose smoking for its costs to public health and the economy but an aggressive tobacco industry campaign and general anti-tax sentiment may block a measure to raise taxes on smokers.

Airwaves in the most populous US state are filling up with advertising for and against Proposition 29, a June 5 ballot measure that would add a $1 tax to a pack of cigarettes, taking the tax to $1.87, mainly to fund medical research on tobacco usage and programs to prevent and control it.