Harm to the respiratory and circulatory systems can come from 
Greenhouse gases hydrocarbons Sulfur dioxide nitrogen oxides burning coal fossil fuels emissions Greenhouse gasses
A B C D E F G H
Nitrogen oxides cause air pollution.
Nitrogen oxides harms the respiratory and circulatory systems.
Harm to the respiratory and circulatory systems can come from  (A) Greenhouse gases (B) hydrocarbons (C) Sulfur dioxide (D) nitrogen oxides (E) burning coal (F) fossil fuels (G) emissions (H) Greenhouse gasses