Secondhand smoke or passive smoke or environmental tobacco smoke (ETS) is a combination of the smoke produced from burning cigarettes and the smoke exhaled by the smoker, from which over 4,000 different chemicals have been identified & around 50 of these chemicals are known carcinogens, a combinatorial effect of which poses a myriad of health risks to communities across the globe. A recent draft report from the Environmental Protection Agency concludes that exposure to environmental tobacco smoke (ETS), which includes the smoke from a burning cigarette as well as "second-hand" or exhaled smoke, causes some 3,000 U.S. lung-cancer deaths and thousands of new cases of childhood asthma each year. ETS is also linked to pneumonia, bronchitis, and other health problems.

A diverse array of testing methods are available nowadays, some are laboratory based while others are used for home testing purposes. Most of these tests provide a quick, accurate and on-the-spot determination of a person's level of exposure to tobacco products either actively or passively i.e. by second hand smoke & allow detection, verification and monitoring of tobacco use status over a period of time. Frequent users of these tests include parents of young children, workers in a smoky workplace, smokers trying to quit, coaches, insurance companies, smoking cessation counselors and other persons concerned about the harmful effects of second hand smoke.

Amongst these tests are various easy to use, non-invasive urine nicotine strip tests which are reasonably fast and accurate & can detect exposure to second hand smoke along with active usage of cigarettes, pipes, cigars etc. Such tests measure the levels of cotinine, a byproduct of the body's breakdown of nicotine which is an active ingredient found in tobacco products and tobacco smoke. Cotinine is a widely accepted indicator of recent tobacco product use and exposure, including second hand smoke exposure.

The end of the urine test strip contains gold particles coated with an antibody that selectively binds to cotinine in the urine. After the end of the strip is dipped in urine, the gold particles migrate through specialized ?traps? in the strip. The more cotinine bound to a gold particle, the further it is able to migrate along the strip. The reddish bands seen on the developed strip correspond to gold particles caught in a particular trap. This test is extremely sensitive and can measure amounts as low as 6 ng of cotinine per milliliter of urine (6 billionths of a gram in one fifth of a teaspoon).

Some techniques have been developed for monitoring carcinogenic pollutants in environmental tobacco smoke & are thousand times more sensitive than previous techniques. In one such technique, two dual computer-programmable fluorescence detectors are used along with high performance liquid chromatography and combined with a unique new sample preparation protocol to screen for a wide range of polycyclic aromatic hydrocarbons and their equally hazardous alkyl derivatives in environmental tobacco smoke. This new technique can work with less than a milligram of sample and enables researchers to identify and estimate the concentrations of both parent and alkyl PAHs (polycyclic aromatic hydrocarbons) with precision and accuracy.