The Seattle Times: Passive smoke is more than a nuisance
May 1998 literature review, published in The Journal of the American Medical Association, evaluated more than 100 major studies on the health effects of passive smoking. 63% found harm, ranging from respiratory problems to cancer. Of the studiess that were inconclusive or found no health effects, three quarters were written by scientists affiliated with the tobacco industry.
http://www.seattletimes.com/news/editorial/html98/smok_080598.html.