Question

Of the 435,000 deaths attributed to tobacco smoking in 2000, how many were caused by secondhand smoke?

Answer 1

In the estimated 435 000 deaths attributable to smoking in the year 2000, there is an inclusion of 35 000 deaths due to secondhand smoking and 1000 infant deaths due to maternal smoking. Secondhand smoke is also called environmental tobacco smoke which contains more than 7000 chemicals that are toxic and can cause cancer. 

Answer 2

The answer is around 35,000 .
Seondhand smoke refers to someone who inhales smoke beside the primary users who smoke the ciggarate, that usualy standing around the primary user when he/she is using.
According to some studies, second-hand smoking might be more harmful because it includes whatever leftover substance that contained in the primary somker's lung.