While countries with higher incomes tend to use more fossil fuels, this increased use itself does not lead to higher life expectancies. A study by the University of Leeds found that a global increase in life expectancy is not directly tied to energy use in general, but rather is more correlated to better living and working conditions and quality of health care.
According to Harvard's public health school, burning and producing fossil fuels of any sort “releases pollutants that lead to early death, heart attacks, respiratory disorders, stroke, exacerbation of asthma, and absenteeism at school and work.” A New York University review concluded that, "If fossil fuel emissions were completely eliminated, the global average life expectancy would increase by 1.1 years."