Material to : Molecular hydrogen ( H 2 ) combustion emissions and their isotope ( D / H ) signatures from domestic heaters , diesel vehicle engines , waste incinerator plants , and biomass burning

The samples were taken from a large variety of burner types, f uel systems, and burning capacities. For each location, two samples (A and B) were taken typically ∼5 min apart. The exhausts of two 5 old (>20 yrs) oil-burner systems were sampled, both from single-f amily houses. In the first case (S-1), the samples were taken from a chimney access in the att ic, about 4 m above the combustion chamber. The first sample (S-1A) was drawn shortly ( ∼2 min) after starting the burner, such that the potential differences between this presumably non-optima l burning and the more optimized burning (S-1B∼20 min after S-1A was collected) could be later investigated . The samples of the second 10 oil-burner system (dating to 1992) were taken from the exhau st pipe at∼1 m from the burner where an exhaust temperature of 170 ◦C was measured (S-2). A variety of natural gas burners were also sampled. The sampl es S-3 were taken from the roof-top chimney exhaust of a 4-party apartment house. The samples S4 were also taken from the roof-top chimney exhaust of a tall 25-party apartment block. The samp les S-5 were taken at the roof-top 15 chimney exhaust (S-5A was 55 ◦C and S-5B was50 C) from two different burner systems of a school complex, where S-5B was from a burner system with a H 2O condensation-recovery system.