Organosulfates from pinene and isoprene over the Pearl River Delta, South China: seasonal variation and implication in formation mechanisms.

Biogenic organosulfates (OSs) are important markers of secondary organic aerosol (SOA) formation involving cross reactions of biogenic precursors (terpenoids) with anthropogenic pollutants. Until now, there has been rare information about biogenic OSs in the air of highly polluted areas. In this study, fine particle (PM2.5) samples were separately collected in daytime and nighttime from summer to fall 2010 at a site in the central Pearl River Delta (PRD), South China. Pinene-derived nitrooxy-organosulfates (pNOSs) and isoprene-derived OSs (iOSs) were quantified using a liquid chromatograph (LC) coupled with a tandem mass spectrometer (MS/MS) operated in negative electrospray ionization (ESI) mode. The pNOSs with MW 295 exhibited higher levels in fall (151 ± 86.9 ng m(-3)) than summer (52.4 ± 34.0 ng m(-3)), probably owing to the elevated levels of NOx and sulfate in fall when air masses mainly passed through city clusters in the PRD and biomass burning was enhanced. In contrast to observations elsewhere where higher levels occurred at nighttime, pNOS levels in the PRD were higher during the daytime in both seasons, indicating that pNOS formation was likely driven by photochemistry over the PRD. This conclusion is supported by several lines of evidence: the specific pNOS which could be formed through both daytime photochemistry and nighttime NO3 chemistry exhibited no day-night variation in abundance relative to other pNOS isomers; the production of the hydroxynitrate that is the key precursor for this specific pNOS was found to be significant through photochemistry but negligible through NO3 chemistry based on the mechanisms in the Master Chemical Mechanism (MCM). For iOSs, 2-methyltetrol sulfate ester which could be formed from isoprene-derived epoxydiols (IEPOX) under low-NOx conditions showed low concentrations (below the detection limit to 2.09 ng m(-3)), largely due to the depression of IEPOX formation by the high NOx levels over the PRD.

[Characterizing spatial patterns of NO(x), SO2 and O3 in Pearl River Delta by passive sampling].

Concentrations of NO(x), SO2 and O3 were measured by passive sampling within 200km x 200km grid in Pearl River Delta (PRD). Sampling period was two weeks in November, 2009. Spatial distributions of NO(x), SO2 and O3 were obtained by Kriging interpolation method. The results were compared with emission inventories and modeling results. The transportations of O3 were evaluated by using backward trajectories of air parcels. During the sampling period, the mean concentrations of NO(x), SO2 and O3 were 75.9 microg/m3, 37.3 microg/m3 and 36.2 microg/m3, respectively. And the highest concentrations of NO(x), SO2 and O3 were 195.7 microg/m3, 95.9 microg/m3 and 81.8 microg/m3. Comparing with routine measurements from the regional monitoring network in PRD, the results by passive method were 18.6%, 33.5% and 37.5% lower for NO(x), SO2 and O3, respectively. The spatial patterns demonstrated that higher NO(x) concentrations often appeared in cities such as Guangzhou, Foshan and Shenzhen. SO2 concentrations were higher in west and lower in east. High SO2 concentrations are mainly from emission of power plants and industrial sources. Concentrations of O3 showed the highest levels in the south of PRD. Backward trajectory analysis for higher ozone areas indicated that 53% of the air masses were from the region with high concentration of NO(x). The horizontal transportation caused higher ozone in the south while lower in north in PRD.

[Anthropogenic ammonia emission inventory and characteristics in the Pearl River Delta Region].

Based on the collected activity data and emission factors of anthropogenic ammonia sources, a 2006-based anthropogenic ammonia emission inventory was developed for the Pearl River Delta (PRD) region by source categories and cities with the use of appropriate estimation methods. The results show: (1) the total NH3 emission from anthropogenic sources in the PRD region was 194. 8 kt; (2) the agriculture sources were major contributors of anthropogenic ammonia sources, in which livestock sources shared 62.1% of total NH3 emission and the contribution of application of nitrogen fertilizers was 21.7%; (3) the broiler was the largest contributor among the livestock sources, accounting for 43.4% of the livestock emissions, followed by the hog with a contribution of 32.1%; (4) Guangzhou was the largest ammonia emission city in the PRD region, and then Jiangmen, accounting for 23.4% and 19.1% of total NH3 emission in the PRD region respectively, with major sources as livestock sources and application of nitrogen fertilizers.

[Development of non-road mobile source emission inventory for the Pearl River Delta region].

Based on the collected activity data and emission factors, the Pearl River Delta (PRD) regional non-road mobile source emission inventory was developed by categories with the use of appropriate estimation methods for different non-road mobile sources. The results show that the total emissions of SO2, NOx,VOC, CO and PM10 from non-road mobile sources in the PRD region were about 6.52 x 10(4) t, 1.24 x 10(5) t, 4.54 x 10(3) t, 2.67 x 10(4) and 4.51 x 10(3) t, respectively. The marine source is the largest non-road mobile source contributor to SO2, NOx, CO and PM10 emissions, accounting for 96.4%, 73.8%, 39.4% and 50.5%, respectively; Freighter and dry bulk carrier are important marine emission contributors, sharing 89.8%, 81.8%, 77.3%, 79.5% and 81.7% of the total marine SO2, NOx, VOC, CO and PM10 emissions. The non-road mobile source has become the third largest SO2 and NOx contributor in the PRD region, accounting for about 8.6% and 13.5% of the regional total SO2 and NOx emissions.

[Monitoring of polychlorinated biphenyls in the atmosphere of the Pearl River Delta using PUF-passive air sampler].

The article research concentration and distribution of atmospheric polychlorinated biphenyls from the Pearl River Delta (PRD) using PUF passive sampling technique. Sampling was conducted at the same time at twenty-one passive sampling sites for consecutive 56 day from August 2005 to October 2005. The results showed middle contaminated levels of PCBs were found in PRD in comparison with other places in the world. Higher contaminated site located FoShan (2 000 pg x m(-3)) in PRD. Concentration range of PCBs are 260 - 2 000 pg x m(-3) and average valuable 670 pg x m(-3) in PRD, 170 - 470 pg x m(-3) and 300 pg x m(-3) in HK. It is obvious that distribution of PCBs in PRD is higher and lower in HK. The results demonstrated that PUF-PAS technique can be used in the monitoring of PAHs in the atmosphere at a regional or global scale.