@article {14695,
	title = {Direct observations of organic aerosols in common wintertime hazes in North China: Insights into direct emissions from Chinese residential stoves.},
	journal = { Atmos. Chem. Phys.},
	volume = {17},
	year = {2017},
	pages = {1259-1270},
	abstract = {Many studies have focused on the physicochemical properties of aerosol particles in unusually severe hazeepisodes in North China instead of the more frequent and lesssevere hazes. Consistent with this lack of attention, the morphology and mixing state of organic matter (OM) particles inthe frequent light and moderate (L \&amp; M) hazes in winter inthe North China Plain (NCP) have not been examined, eventhough OM dominates these fine particles. In the presentwork, morphology, mixing state, and size of organic aerosolsin the L \&amp; M hazes were systematically characterized using transmission electron microscopy coupled with energydispersive X-ray spectroscopy, atomic force microscopy, andnanoscale secondary ion mass spectrometer, with the comparisons among an urban site (Jinan, S1), a mountain site(Mt. Tai, S2), and a background island site (Changdao, S3)in the same hazes. Based on their morphologies, the OM particles were divided into six different types: spherical (type 1),near-spherical (type 2), irregular (type 3), domelike (type 4),dispersed-OM (type 5), and OM-coating (type 6). In the threesampling sites, types 1{\textendash}3 of OM particles were most abundant in the L \&amp; M hazes and most of them were internallymixed with non-OM particles. The abundant near-sphericalOM particles with higher sphericity and lower aspect ratioindicate that these primary OM particles formed in the cooling process after polluted plumes were emitted from coalcombustion and biomass burning. Based on the Si-O-C ratio in OM particles, we estimated that 71 \% of type 1{\textendash}3 OMparticles were associated with coal combustion. Our resultsuggests that coal combustion in residential stoves was awidespread source from urban to rural areas in NCP. AverageOM thickness which correlates with the age of the air massesin type 6 particles only slightly increased from S1 to S2 to S3,suggesting that the L \&amp; M hazes were usually dry (relativehumidity \&lt; 60 \%) with weak photochemistry and heterogeneous reactions between particles and gases. We concludethat the direct emissions from these coal stoves without anypollution controls in rural areas and in urban outskirts contribute large amounts of primary OM particles to the regionalL \&amp; M hazes in North China.},
	author = {SR Chen and L. Xu and YX Zhang and B. Chen and XF Wang and X.Y. Zhang and M* Zheng and JM Chen and WX Wang and Sun, Y. L. and Fu, P. Q. and Wang, Z. F. and Li, W. J.}
}
