%D 2011 %0 Publisher %T CHARACTERIZATION OF PARTICULATE MATTER EMISSION FROM OPEN BURNING OF RICE STRAW . %J Atmos Environ %V 45 %P 493-502 %A Oanh NT %A Bich TL %A Tipayarom D %A Manadhar BR %A Prapat P %A Simpson CD %A Liu LJ %M pub21243095 %X Emission from field burning of crop residue , a common practice in many parts of the world today , has potential effects on air quality , atmosphere and climate . This study provides a comprehensive size and compositional characterization of particulate matter ( PM ) emission from rice straw ( RS ) burning using both in situ experiments ( 11 spread field burning ) and laboratory hood experiments ( 3 pile and 6 spread burning ) that were conducted during 2003-2006 in Thailand . The carbon balance and emission ratio method was used to determine PM emission factors ( EF ) in the field experiments . The obtained EFs varied from field to hood experiments reflecting multiple factors affecting combustion and emission . In the hood experiments , EFs were found to be depending on the burning types ( spread or pile ) , moisture content and the combustion efficiency . In addition , in the field experiments , burning rate and EF were also influenced by weather conditions , ie wind . Hood pile burning produced significantly higher EF ( 20+/-8 g kg ( -1 ) RS ) than hood spread burning ( 4 . 7+/-2 . 2 g kg ( -1 ) RS ) . The majority of PM emitted from the field burning was PM ( 2 . 5 ) with EF of 5 . 1+/-0 . 7 g m ( -2 ) or 8 . 3+/-2 . 7 g kg ( -1 ) RS burned . The coarse PM fraction ( PM ( 10-2 . 5 ) ) was mainly generated by fire attention activities and was relatively small , hence the resulting EF of PM ( 10 ) ( 9 . 4+/-3 . 5 g kg ( -1 ) RS ) was not significantly higher than PM ( 2 . 5 ) . PM size distribution was measured across 8 size ranges ( from <0 . 4 mum to >9 . 0 mum ) . The largest fractions of PM , EC and OC were associated with PM ( 1 . 1 ) . The most significant components in PM ( 2 . 5 ) and PM ( 10 ) include OC , water soluble ions and levoglucosan . Relative abundance of some methoxyphenols ( eg , acetylsyringone ) , PAHs ( eg , fluoranthene and pyrene ) , organochlorine pesticides and PCBs may also serve as additional signatures for the PM emission . Presence of these toxic compounds in PM of burning smoke increases the potential toxic effects of the emission . For illustration , an estimation of the annual RS field burning in Thailand was made using the obtained in situ field burning EFs and preliminary burning activity data .