Quitting smoking after year and a half, what are negative effects?

There really aren't: any truly negative effects. However, short-term you may experience an increase in cough and sputum production, as your lungs try to clear themselves after that year and a half of throwing junk into them. This may last for a week or two, rarely longer, but will improve. Some people get increased appetite and gain weight, and people with depression may feel more depressed. Get support/help from MD