Spain's anti-smoking laws improve air quality.

Nebot M, M López, C Ariza, M Pérez-Ríos, M Fu, A Schiaffino, G Munñz, E Saltó and E Fernández. Impact of the Spanish smoking law on exposure to secondhand smoke in offices and hospitality venues: before-and-after study. Environmental Health Perspectives doi:10.1289/ehp.11845.

One year after a ban on smoking in all work places and some hospitality venues in Spain, nicotine levels in the air were significantly diminished -- up to 97 percent in some cases -- in offices and were much lower in nonsmoking areas of restaurants and bars.

The reductions are important because evidence linking secondhand smoke to adverse health effects has been growing. Even small exposures to the cancer-causing agents found in tobacco smoke increase the risk of cancer.

Worldwide, the most effective public health efforts to curb exposure have been laws that ban smoking. This new study confirms these prior examples.

In 2006, Spain joined other European countries in banning indoor smoking in the workplace. For this study, public administration offices, businesses, universities, bars and restaurants in eight regions of Spain were sampled at the end of 2005, just prior to when the ban started. Twelve months later, samples were collected from the same locations.

Nicotine levels in places with total bans were significantly lower. Non-smoking areas in bars and restaurants also had large reductions in nicotine measured, almost 89 percent less. Places where smoking remained had no reductions.