This table provides critical combustion product data for natural gas (CH₄), diesel (C₁₂H₂₃), and bituminous coal, comparing flue gas composition and thermodynamic properties across varying air-fuel ratios (λ). Key trends reveal how increasing λ (from stoichiometric to 50% excess air) reduces CO₂ concentration (e.g., methane drops from 9.5% to 6.3% vol) and adiabatic flame temperature (methane: 1950°C → 1500°C), while increasing O₂ content. The data highlights fuel-specific behaviors—coal produces SO₂ (1200 ppm at λ=1) and higher CO₂ concentrations than hydrocarbons—enabling engineers to optimize burner designs, predict emissions, and size heat recovery systems. All values assume complete combustion with dry air at standard conditions.