Field measurements were conducted to determineparticulate emissions and trace gas emissions, includingCO
2, CO, CH
4, NMHCs, NO
x, NH
3, N
2O, and SO
2, from openburning of wheat straw and maize stover, two majoragricultural residues in China. The headfire ignition techniquewas adopted, and samp
ling was performed downwindfrom the agricultural fire. Particulate matter (PM) and gasemission factors were determined using the carbon mass-balance method. Particle mass size distributions showa prominent accumulation mode peak at 0.26-0.38
![](/images/entities/mgr.gif)
m.Submicron particles dominate PM emissions. Most measuredchemical species measured show a similar size distributionas PM. Chemical composition analysis indicates thatPM
2.5 is largely composed of carbon, K, and Cl. PM
2.5emission factors of wheat straw and maize stover are 7.6± 4.1 g/kg and 11.7 ± 1.0 g/kg, respectively. It alsoindicates that 12.1-24.2% of N in biomass is released asnitrogen-based trace gases and 11.0-24.9% of fuel S is emittedas SO
2.