Are E Cigarettes a Healthy Way to Quit Smoking? WSJ Formaldehyde Higher in E Cigarettes than Previously Reported, say researchers Chemical Free Life Formaldehyde in E cigarettes, a Major Concern Electronic cigarette aerosol contains 6 times less formaldehyde than tobacco cigarette smoke Nicorex E Cigarette How E Cigarettes Work, Health Risks & Teen Use US health watchdog to take legal action against e cigarette makers California The Guardian