Search

Isoprene (2‐methyl‐1, 3‐butadiene) is a nonmethane volatile organic compound (VOC) with the largest global emission and high reactivity. The oxidation of isoprene is crucial to atmospheric photochemistry and contributes significantly to the global formation of secondary organic aerosol. Here, we conducted comprehensive observations in polluted megacities of Nanjing and Shanghai during summer of 2018. We identified multiple functionalized isoprene oxidation products, of which 72% and 88% of the total mole concentration were nitrogen‐containing species with the dominant compound being C5 dihydroxyl dinitrate (C5H10N2O8). We calculated the volatility using the group‐contribution method and estimated the particle‐phase concentration by equilibrium gas/particle partitioning. The results showed that the multifunctional products derived from isoprene oxidation can contribute to 2.6% of the total organic aerosol mass (0.28 ± 0.27 μg/m3), highlighting the potential importance of isoprene oxidation in polluted regions. Plain Language Summary: Isoprene, as one of the most important precursors to form secondary organic aerosol (SOA) globally, has been extensively studied, most of which however focused in the pristine regions. In polluted urban areas, where isoprene would interact significantly with anthropogenic emissions, for example, NOx, the understanding of SOA formation potential of isoprene is rather controversial. Here, we used state‐of‐the‐art instruments to measure isoprene, highly functionalized intermediate compounds and organic aerosol simultaneously at two suburban sites in eastern China region and identify several tens of isoprene oxidation products with most of which identified as nitrogen‐containing species, confirming the significant interaction between the isoprene derived peroxy radicals and NOx. These multifunctional products are mostly semi‐volatile species and can contribute considerably to the observed SOA, highlighting an important role of biogenic volatile organic compounds oxidation on SOA formation under high‐NOx conditions, for example, anthropogenic emission dominant regions. Key Points: Simultaneous measurements of volatile organic compounds, highly functionalized intermediate compounds and organic aerosol were conductedOrganic nitrates dominated the C4‐C5 functionalized isoprene oxidation products detected by NO3− CIMSMost of the identified isoprene oxidation products were categorized as SVOC and can contributed to secondary organic aerosol [ABSTRACT FROM AUTHOR]

An intensive investigation of carbonaceous PM2.5 and TSP (total suspended particles) from Pudong (China) was conducted as part of the MIRAGE-Shanghai (Megacities Impact on Regional and Global Environment) experiment in 2009. Data for organic and elemental carbon (OC and EC), organic species, including C17 to C40 n-alkanes and 17 polycyclic aromatic hydrocarbons (PAHs), and stable carbon isotopes OC (δ13COC) and EC (δ13CEC) were used to evaluate the aerosols' temporal variations and identify presumptive sources. High OC/EC ratios indicated a large fraction of secondary organic aerosol (SOA); high char/soot ratios indicated stronger contributions to EC from motor vehicles and coal combustion than biomass burning. Diagnostic ratios of PAHs indicated that much of the SOA was produced via coal combustion. Isotope abundances (δ13COC=-24.5±0.8‰ and δ13CEC=-25.1±0.6‰) indicated that fossil fuels were the most important source for carbonaceous PM2.5 (particulate matter less than 2.5 micrometers in diameter), with lesser impacts from biomass burning and natural sources. An EC tracer system and isotope mass balance calculations showed that the relative contributions to total carbon from coal combustion, motor vehicle exhaust, and SOA were 41%, 21%, and 31%; other primary sources such as marine, soil and biogenic emissions contributed 7%. Combined analyses of OC and EC, n-alkanes and PAHs, and stable carbon isotopes provide a new way to apportion the sources of carbonaceous particles. [ABSTRACT FROM AUTHOR]

In this study, we first investigated the prevalence of astrovirus in stools of dogs with and without diarrhea in Shanghai, China. Of all the specimens, 22 (12.02%) from the 183 dogs with diarrhea and none (0%) from the 138 healthy controls were positive for astrovirus. Furthermore, we cloned partial sequences of ORF1b (442 bp) and the entire sequences of ORF2 (2475 bp). Phylogenetic analysis showed that the new isolates were belonged to genus Mamastrovirus and most closely clustered with the Italy strain, based on the ORF2 sequences available. However, the new isolates and the Italy strain were divided into two different clusters. The new isolates may be a new strain of canine astrovirus. [ABSTRACT FROM AUTHOR]