Characteristics and sources of non‐methane hydrocarbons in background atmospheres of eastern, southwestern, and southern China

Abstract

Non‐methane hydrocarbons (NMHCs) play very important roles in atmospheric chemistry, yet little is known about their abundance in the atmosphere of China, especially in the background atmospheres. Measurements of C2‐C10 NMHCs were concurrently carried out at two remote background sites and one rural background site in April and May 2004 in this study: Tengchong Mountain (TM) in Yunnan province on the border of southwestern China; Jianfeng Mountain (JM) on the southwest coast of Hainan Island, southern China; and Lin'an (LA) in Zhejiang province in eastern China. Additional samples were collected at an urban site, Tengyue Town (TT, about 10 km from TM), to obtain local urban NMHC profiles. NMHC levels in these background sites were compared with other rural and remote sites in Asia and other global background stations. In the urban site of TT, local biofuel combustion was the major contributor to the high levels of ethene, ethyne, and ethane. In LA, the major sources of NMHCs were the emissions from fossil fuel and biofuel combustion and from industrial solvent use. Compared with another study conducted in 2001, toluene levels had increased by 75% in 2004 in this study, whereas the levels of other anthropogenic hydrocarbons remained at the same levels. Local industrial emissions and transports from the Yangtze River Delta were the major sources of toluene, ethylbenzene, and xylenes in LA. While in TM, the major sources were regional biofuel combustions and biomass burning emissions from Southeast Asia. Long‐range transport of air masses from Southeast Asia was the major source of NMHCs in JM in spring. JM showed the lowest levels of most hydrocarbons among the three background sites. Several hydrocarbon molar ratios, such as benzene/toluene and ethane/propane, were used to characterize the signatures of air masses from different regions.

Source attributions of hazardous aromatic hydrocarbons in urban, suburban and rural areas in the Pearl River Delta (PRD) region

“…Acetylene, for example, had been used extensively as a tracer for combustion [4,28,[60][61][62][63][64][65], and the ratios of hydrocarbons to acetylene were widely used to examine the impact of other emissions sources relative to combustion emissions. The ratios of propane, n-butane and i-butane to acetylene, for example, have been used to indicate their contribution from LPG leakage [28,60].…”

Ambient air benzene at background sites in China's most developed coastal regions: Exposure levels, source implications and health risks

“…3. Average mixing ratios of 578-1297 pptv for benzene at the four sites fell within that of 570-1914 pptv reported at other rural sites in China's developed regions, such as NCP (Suthawaree et al, 2010(Suthawaree et al, , 2012Yuan et al, 2013), YRD (Guo et al, 2004;Tang et al, 2009), PRD Table 1 Statistics of benzene mixing ratios (pptv), exposure levels and health risks at the four background sites. Number in parentheses indicates the total number of samples at each site.…”

“…Monitoring of benzene levels at more background sites would, therefore, not only reveal background exposure levels, but also reflect the impact of regional social-economic changes. Unfortunately, monitoring at background or remote locations is scarce and sporadic in China (Guo et al, 2004;Tang et al, 2009;Suthawaree et al, 2010;Xue et al, 2013;Zhang et al, 2014). To fully understand the exposure levels and the potential health risks, long-term measurements are needed.…”

Atmospheric polybrominated diphenyl ethers (PBDEs) and Pb isotopes at a remote site in Southwestern China: Implications for monsoon-associated transport

“…1). Details on the sampling site can be found elsewhere (Tang et al, 2009 (QMA,20.3 × 25.4 cm,Whatman,Maidstone,England) and pre-cleaned polyurethane foam (PUF) plugs (6.5 cm diameter, 7.5 cm length, 0.030 g cm − 3 density) were used to collect the particulate and gas phase samples, respectively. The QFFs were baked in a muffle furnace at 450°C for 4 h. The PUF plugs were precleaned twice by an Accelerated Solvent Extraction with a mixture (1:1, V/V) of acetone and dichloromethane (DCM) at 100°C and 1500 psi for 15 min.…”

“…However, Pearson correlation analysis results indicate that local temperature, wind speed, relative humidity and precipitation did not exert statistically significant influence (p N 0.05) on PBDE congeners at this site during our sampling campaign. The lack of temperaturedependence of gas-phase BDE concentrations is likely a result of longrange transport rather than local ongoing sources, as there are very few industrial enterprises nearby (Tang et al, 2009). …”