Characteristics of organic and elemental carbon in PM2.5 samples in Shanghai, China

doi:10.1016/j.atmosres.2009.01.003

Atmospheric Research

Volume 92, Issue 4, June 2009, Pages 434-442

https://doi.org/10.1016/j.atmosres.2009.01.003 Get rights and content

Abstract

Shanghai is the largest industrial and commercial city in China, and its air quality has been deteriorating for several decades. However, there are scarce researches on the level and seasonal variation of fine particle (PM_2.5) as well as the carbonaceous fractions when compared with other cities in China and around the world. In the present paper, abundance and seasonal characteristics of PM_2.5, organic carbon (OC) and elemental carbon (EC) were studied at urban and suburban sites in Shanghai during four season-representative months in 2005–2006 year. PM_2.5 samples were collected with high-vol samplers and analyzed for OC and EC using thermal-optical transmittance (TOT) protocol. Results showed that the annual average PM_2.5 concentrations were 90.3–95.5 μg/m³ at both sites, while OC and EC were 14.7–17.4 μg/m³ and 2.8–3.0 μg/m³, respectively, with the OC/EC ratios of 5.0–5.6. The carbonaceous levels ranked by the order of Beijing > Guangzhou > Shanghai > Hong Kong. The carbonaceous aerosol accounted for ∼ 30% of the PM_2.5 mass. On seasonal average, the highest OC and EC levels occurred during fall, and they were higher than the values in summer by a factor of 2. Strong correlations (r = 0.79–0.93) between OC and EC were found in the four seasons. Average level of secondary organic carbon (SOC) was 5.7–7.2 μg/m³, accounting for ∼ 30% of the total OC. Strong seasonal variation was observed for SOC with the highest value during fall, which was about two times the annual average.

Introduction

Carbonaceous aerosol constitutes a significant fraction of fine particles (PM_2.5), and it could account for up to 40% of PM_2.5 mass in urban atmosphere (Seinfeld and Pandis, 1998). Carbonaceous species are usually classified into elemental carbon (EC) and organic carbon (OC). EC (sometimes called black carbon) derived from incomplete combustion of carbon-contained materials, while OC can be either released directly into the atmosphere (primary OC, POC) or produced from gas-to-particle reactions (secondary OC, SOC) (Pandis et al., 1992, Turpin and Huntzicker, 1995). EC has strong absorption of solar radiation and is one of the important drivers of global warming (Hansen et al., 2005). OC represents a mixture of hundreds of organic compounds, some of which are mutagenic and/or carcinogenic, such as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) (Feng et al., 2006, Li et al., 2008).

Carbonaceous aerosol in China has drawn special attention in recent years due to its adverse effects on environment and human health and potential influence on climate change (Hamilton and Mansfield, 1991, Qiu and Yang, 2000, Jacobson, 2002). It has been estimated that China contributes roughly one-fifth of the global carbonaceous emissions (Bond et al., 2004). Jacobson (2002) suggested that emission reduction of fossil-fuel carbonaceous particles was possibly the most effective method of slowing global warming. The increased EC aerosols may be responsible for the significant variation of precipitation in eastern China over the past decades (Menon et al., 2002). EC also contributed to the marked degradation of optical depths and visibility in northern China (Qiu and Yang, 2000), and lowered the crop yields by reducing solar radiation that reaches the earth (Chameides et al., 1999).

There are several studies focusing on the field measurements of carbonaceous abundance in PM_2.5 in China's industrialized areas, such as Guangzhou and Hong Kong in Pearl River Delta Region (Ho et al., 2002, Ho et al., 2003, Ho et al., 2006, Cao et al., 2003, Cao et al., 2004, Cao et al., 2005, Chow et al., 2005, Duan et al., 2007), Beijing (He et al., 2001, He et al., 2004a, Dan et al., 2004, Duan et al., 2006), and other cities (Guo et al., 2004, Cao et al., 2005, Yang et al., 2005b). However, there are only limited studies in Shanghai (Ye et al., 2003, Yang et al., 2005a, Feng et al., 2006), which is the largest commercial and industrial city in China and also one of the world's largest seaports. World Expositions will be held here in 2010. Furthermore, one-year carbonaceous measurements by Ye et al. (2003) and Yang et al. (2005a) were finished during 1999–2000 year, and since then the air pollution in Shanghai is ameliorating observably. For example, annual PM₁₀ concentration in Shanghai was 100.5 μg/m³ in 2001 versus 86.2 μg/m³ in 2006 (http://www.envir.gov.cn/airnews/).

Ambient air quality in Shanghai began to deteriorate in the 1960s due to large consumption of low-quality coal for rapid industrial development. When coal smoke was somewhat controlled in the 1990s, vehicular population in Shanghai soared up to ∼ 2 million, and the type of air pollution in Shanghai evolved into the combination of coal smoke with vehicular exhaust (Chen, 2003). Great concern on the visibility reduction and public health has been drawn by the heavy PM pollution in Shanghai (Ye et al., 2000), and the primary carbonaceous emission in 2000 was about 16.3 Gg (gigagrams or ktons) for EC and 34.0 Gg for OC (Cao et al., 2006).

The purpose of this paper is to present updated knowledge on abundance and seasonal characteristics of PM_2.5-associated EC and OC in Shanghai, which is helpful to investigate of their sources and PM control strategies.

Section snippets

Sampling sites description

Shanghai is located at the east end of the Yangtze River Delta Region and faces the East China Sea (Fig. 1), and possesses a population of over 15 million and a land area of about 6340 km². Shanghai belongs to the northern subtropical monsoon climate, and northwest wind prevails in wintertime whereas southeast wind in summertime. Annual average of temperature in Shanghai is 15.8 °C, with the lowest in January (3.6 °C) and the highest in July (27.8 °C).

In this study, two sites were selected for

Levels of PM_2.5, OC and EC in Shanghai

The statistics for PM_2.5 mass, OC and EC at both sampling sites in Shanghai are presented in Table 1. Firstly, it can be seen that the levels of PM_2.5 and carbonaceous fractions at suburban site (JD) (95.5 ± 41.8 μg/m³) are a little higher than that at urban site (ZB) (90.3 ± 54.9 μg/m³), suggesting that fine particle pollution occurred not only in the urban, but also in the suburban area of Shanghai. Similar situation was observed by Feng et al. (2006) that there was no clear difference of

Conclusions

Abundance and seasonal characteristics of PM_2.5 and carbonaceous species were investigated at two sites at Shanghai, China. On annual average, PM_2.5 concentration was 90.3 μg/m³ at ZB Site and 95.5 μg/m³ at JD, indicating the serious situation of fine particle pollution in Shanghai. The concentrations for OC and EC were 14.7 and 2.8 μg/m³ at ZB whereas 17.4 and 3.0 μg/m³ at JD, respectively, following the order of Beijing > Guangzhou > Shanghai > Hong Kong. Carbonaceous aerosol (TCA) accounted

Acknowledgements

This project was financially supported by the Department of Science and Technology of Shandong Province (2006GG2205033, 2007GG2QT06018), National Natural Scientific Foundation of China (40605033, 40503012), and Shanghai Leading Academic Disciplines (S30109). The authors would like to thank Jia-ding Environmental Monitoring Station in Shanghai for the assistant of sampling at the station, Dr. Xiyong Hou from YIC, CAS and Ms. Paromita Chakraborty from GIG, CAS for their helps in this manuscript.

References (54)

CaoJ.J. et al.
Characteristics of carbonaceous aerosol in Pearl River Delta Region, China during 2001 winter period
Atmospheric Environment
(2003)
CaoJ.J. et al.
Spatial and seasonal variations of atmospheric organic carbon and elemental carbon in Pearl River Delta Region, China
Atmospheric Environment
(2004)
CaoG. et al.
Inventory of black carbon and organic carbon emissions from China
Atmospheric Environment
(2006)
CastroL.M. et al.
Carbonaceous aerosol in urban and rural European atmospheres: estimation of secondary organic carbon concentrations
Atmospheric Environment
(1999)
ChowJ.C. et al.
Descriptive analysis of PM2.5 and PM10 at regionally representative locations during SJVAQS/AUSPEX
Atmospheric Environment
(1996)
ChowJ.C. et al.
Comparison of PM2.5 carbon measurement methods in Hong Kong, China
Environmental Pollution
(2005)
DanM. et al.
The characteristics of carbonaceous species and their sources in PM2.5 in Beijing
Atmospheric Environment
(2004)
DuanF.K. et al.
Concentration and chemical characteristics of PM2.5 in Beijing, China: 2001–2002
Science of the Total Environment
(2006)
DuanJ.C. et al.
Sources and characteristics of carbonaceous aerosol in two largest cities in Pearl River Delta Region, China
Atmospheric Environment
(2007)
FanX. et al.
Measurement of organic and elemental carbon associated with PM2.5 during Pacific 2001 study using an integrated organic gas and particle sampler
Atmospheric Environment
(2004)

VianaM. et al.

Comparative analysis of organic and elemental carbon concentrations in carbonaceous aerosols in three European cities

Atmospheric Environment

(2007)

ViidanojaJ. et al.

Organic and black carbon in PM2.5 and PM10: 1 year of data from an urban site in Helsinki, Finland

Atmospheric Environment

(2002)

Cited by (249)

Variations of oxidative potential of PM<inf>2.5</inf> in a medium-sized residential city in South Korea measured using three different chemical assays
2024, Science of the Total Environment
Although it is evident that PM_2.5 has serious adverse health effects, there is no consensus on what the biologically effective dose is. In this study, the intrinsic oxidative potential (OPm) and the extrinsic oxidative potential (OPv) of PM_2.5 were measured using three chemical assays including dithiothreitol (DTT), ascorbic acid (AA), and reduced glutathione (GSH), along with chemical compositions of PM_2.5 in South Korea. Among the three chemical assays, only OPm^AA showed a statistically significant correlation with PM_2.5 while OPm^GSH and OPm^DTT were not correlated with PM_2.5 mass concentration. When the samples were categorized by PM_2.5 mass concentrations, the variations in the proportion of Ni, As, Mn, Cd, Pb, and Se to PM_2.5 mass closely coincided with changes in OPm across all three assays, suggesting a potential association between these elements and PM_2.5 OP. Multiple linear regression analysis identified the significant PM components affecting the variability in extrinsic OPv. OPv^AA was determined to be significantly influenced by EC, K⁺, and Ba while OC and Al were common significant factors for OPv^GSH and OPv^DTT. It was also found that primary OC was an important variable for OPv^DTT while secondary OC significantly affected the variability of OPv^GSH.
Fine particulate matter from brick kilns site and roadside in Lahore, Pakistan: Insight into chemical composition, oxidative potential, and health risk assessment
2024, Heliyon
Human health is seriously threatened by particulate matter (PM) pollution, which is a major environmental problem. A better indicator of biological responses to PM exposure than its mass alone is the PM "oxidative potential (OP)," or ability to oxidize target molecules. When reactive oxygen species (ROS) are generated in the OP in excess of the antioxidant capacity of body due to PM components such metals and organic species, it causes inflammation, deoxyribonucleic acid (DNA), proteins, and lipids damage.
The samples of fine particulate matter (PM_2.5) are collected from the brick kiln site and the roadside in Lahore, Pakistan. The organic carbon (OC) and elemental carbon (EC) were estimated by carbon analyzer (DRI 2001A) using the thermal/optical transmittance (TOT) protocol. The water-soluble organic carbon (WSOC) concentration was determined using a total organic carbon analyzer (Shimadzu TOC-L CPN). Ion chromatography (Dionex ICS–900) with a conductivity detector was used to analyze the water-soluble anions (Cl⁻, NO₃⁻, and SO₄²⁻) and cations (NH₄⁺, Na⁺, K⁺, Mg²⁺, and Ca²⁺). Inductively coupled plasma-mass spectrometry (iCAP TQ ICP-MS, Thermo Scientific) was used to determine the concentrations of metals in the solution. The dithiothreitol (DTT) consumption rate was calculated using a spectrophotometer at a wavelength of 412 nm.
The mean concentrations of PM_2.5 at the brick kiln site and roadside reported are 509.3 ± 32.3 μg/m³ and 467.5 ± 24.9 μg/m³, and the average OC/EC ratio is 1.9 ± 0.4 and 2.1 ± 0.1. primary organic carbon (POC) contributed more to OC than secondary organic carbon (SOC), which indicated the dominance of primary combustion sources. The anion equivalent (AE) to cation equivalent (CE) ratio indicated that PM_2.5 is acidic at both sites due to the dominance of NO₃⁻ and SO₄²⁻. The DTT consumption rate normalized by PM_2.5 mass (DTT_m) and DTT consumption rate normalized by air volume (DTT_v) of PM_2.5 at the roadside samples are higher than at the brick kiln site due to the higher contribution of ionic species to the mass of PM_2.5. Carbonaceous species of PM_2.5 at both sampling sites are significantly correlated with DTTv of PM_2.5, while metallic species behaved differently. The incremental lifetime cancer risk (ILCR) values (lung cancer) of As and Cr at both sampling sites, while the ILCR value of Cd at the roadside samples is exceeding the permissible limits for adults and children. The lifetime average daily dose (LADD) value for adults is higher than that for children, indicating that children are less vulnerable to metals.
The concentration of PM_2.5 at both sampling sites were exceeding the permissible limits of Pakistan’ National Environmental Quality Standard (NEQS) and posing risk to the health of the local population. The POC and SOC contribution to OC at the brick kiln site and roadside in Lahore were 84.6%, 15.4% and 84.4%, 15.6%. POC at both sampling sites were the dominant carbon species indicating the dominance of primary combustion sources. The residence of Lahore poses the lung cancer risk due to Cr, As, and Cd at both sampling sites. The results of this study provide important data and evidence for further evaluation of the potential health risks of PM_2.5 from brick kiln site and road side in Pakistan and formulation of efficient air-pollution control measures.
Characterization and sources of carbonaceous aerosols in southwest plateau of China: Effects of biomass burning and low oxygen concentration
2024, Atmospheric Environment
Carbonaceous aerosols affect atmospheric radiation and visibility and endanger human health. Administrative border and topography have created significant research interests focused on Yunnan Province. We studied the chemical characteristics and sources of OC and EC in four Yunnan cities using manual sampling and positive definite matrix factorization (PMF). Backward trajectories, cluster analysis, potential source contribution function (PSCF) and concentration-weighted trajectory (CWT) were used to evaluate the transport pathways and potential source of carbonaceous aerosols during spring. The impacts of the transport of Biomass burning (BB) emissions in Southeast Asia and incomplete combustion on carbonaceous aerosols were highlighted in the study. Daily PM_2.5 concentration ranged from 12.00 μg/m³ to 91.50 μg/m³, with the average concentration of 34.03 ± 13.49 μg/m³. OC and EC accounted for 19.85–44.94 % and 4.99–13.16 % of PM_2.5. Average secondary organic carbon (SOC) concentration ranged from 0.82 μg/m³ ∼ 6.42 μg/m³, exhibiting the highest secondary conversion rate in autumn. BB was identified as the largest single source of carbonaceous aerosols through PMF analysis. The results of backward trajectory showed that more than 63.68 % of air mass originated from Myanmar in spring, and Myanmar, Laos and Vietnam were identified as the major potential source areas by PSCF and CWT. Biomass plumes emitted by some Southeast Asian countries in the spring are likely to be transported to the Yunnan Province under the guidance of southwest winds, thereby affecting local carbonaceous aerosols. The proportions of OC and EC in PM_2.5 of the Yunnan Plateau were found higher than those in the four plains of China (Northeast Plain, North China, Middle-Lower Yangtze, and Guanzhong Plain). Incomplete combustion caused by low oxygen concentrations at high altitudes was considered as the cause.
Characteristics, seasonal variations, and dry deposition fluxes of carbonaceous and water-soluble organic components in atmospheric aerosols over China's marginal seas
2023, Marine Pollution Bulletin
A total of 37 atmospheric aerosol samples were collected over the Yellow and Bohai Seas (YBS) during four cruises in autumn, winter, spring and summer from 2017 to 2018. The concentrations of organic carbon (OC) and water-soluble organic carbon (WSOC) ranged from 1.04 to 15.43 μg m⁻³ and 0.77–5.49 μg m⁻³, respectively, with higher values in autumn and winter than in spring and summer. WSOC contributed 68.49 % to OC in summer and 34.55 % in winter and was affected by temperature and relative humidity. Dicarboxylic acid showed a predominance of oxalic acid followed by malonic and then succinic acids. The contributions of secondary sources to OC and WSOC were 54 % and 65.3 %, respectively, indicating the importance of secondary aging in improving the water solubility of OC. The dry deposition flux of WSOC over the YBS was estimated to be 0.87 mg m⁻² d⁻¹, which might play a potential role in the marine carbon cycle.
Assessment of traffic-related chemical components in ultrafine and fine particles in urban areas in Vietnam
2023, Science of the Total Environment
Ultrafine particles (UFPs or PM_0.1; aerodynamic diameter ≤ 0.1 μm) were monitored at a roadside site (RS) in a populated area of Hanoi, Vietnam. Meanwhile, UFPs and fine particles (FPs or PM_2.5, aerodynamic diameter ≤ 2.5 μm) were monitored at an ambient site (AS), located at an on-campus a university, approximately 200 m away from the RS. Sampling was conducted in different seasons–summer, winter, and the transitional periods of summer-to-winter and winter-to-summer (STP and WTP, respectively). Carbonaceous and ionic species in UFPs and FPs–rarely investigated in the study area–were analyzed to observe the seasonal variations, characteristics of UFPs near the roadway, and spatial differences between the sites. The UFPs concentration at the AS was in the order of winter > STP > WTP > summer, whereas that of the FPs was winter > WTP > STP > summer. This seasonal variation of particle concentration was possibly affected by the meteorological conditions, which contribute to the highest concentration in winter. The higher FPs concentration in WTP than in STP resulted from the substantial increase in ionic concentrations, particularly sulfate, nitrate, and ammonium. This result indicates the effect of secondary formation processes under drizzle-like weather, which is typical during WTP in northern Vietnam. Compared with UFPs at the AS, traffic-related emissions were more noticeable in UFPs at the RS, including a higher EC concentration and lower OC/EC ratio. The possibility of particle growth under favorable conditions, including the presence of gas-phase pollutants and the availability of surface areas owing to high UFPs concentration in Hanoi, may explain the low correlation of the chemical components between UFPs and FPs in the sites. This study serves as a reference for further investigation of the relationship between UFPs and FPs under highly polluted conditions in big cities in Vietnam in future studies.
Hourly organic tracers-based source apportionment of PM<inf>2.5</inf> before and during the Covid-19 lockdown in suburban Shanghai, China: Insights into regional transport influences and response to urban emission reductions
2022, Atmospheric Environment
During the Covid-19 outbreak, strict lockdown measures led to notable reductions in transportation-related emissions and significantly altered atmospheric pollution characteristics in urban and suburban areas. In this work, we compare comprehensive online measurements of PM_2.5 major components and organic molecular markers in a suburban location in Shanghai, China before lockdown (Dec. 28, 2019 to Jan. 23, 2020) and during lockdown (Jan. 24 to Feb. 9, 2020). The NO_x levels declined sharply by 59% from 44 to 18 ppb during the lockdown, while O₃ rose two times higher to 42 ppb. The PM_2.5 level dropped from 64 to 49 μg m⁻³ (−24%). The major components all showed reductions, with the reduction of nitrate most prominent at −58%, followed by organics at −19%, and sulfate at −17%. Positive matrix factorization analysis identifies fourteen source factors, including nine primary sources and five secondary sources. The secondary sources consist of sulfate-rich factor, nitrate-rich factor, and three secondary organic aerosol (SOA) factors, with SOA_I being anthropogenic SOA, SOA_II associated with later generation products of organic oxidation, and SOA_III being biogenic SOA. The combined secondary sources contributed to 69% and 63% (40 and 22 μg m⁻³) of PM_2.5 before and during lockdown, respectively, among which the reductions in the nitrate-rich (−55%) factor was the most prominent. Among primary sources, large reductions (>80%) were observed in contributions from industrial, cooking, and vehicle emissions. Unlike some studies reporting that the restriction during the Covid-19 resulted in enhanced secondary sulfate and SOA formation, we observed decreases in both secondary inorganic and SOA formation despite the overall elevated oxidizing capacity in the suburban site. Our results indicate that the formation change in secondary inorganic and organic compounds in response to substantial reductions in urban primary precursors are different for urban and suburban environments.

View all citing articles on Scopus

View full text

Characteristics of organic and elemental carbon in PM2.5 samples in Shanghai, China

Abstract

Introduction

Section snippets

Sampling sites description

Levels of PM2.5, OC and EC in Shanghai

Conclusions

Acknowledgements

Atmospheric Environment

Atmospheric Environment

Atmospheric Environment

Atmospheric Environment

Atmospheric Environment

Environmental Pollution

Atmospheric Environment

Science of the Total Environment

Atmospheric Environment

Atmospheric Environment

Journal of Hazardous Materials

Chemosphere

Atmospheric Environment

Atmospheric Environment

Atmospheric Environment

Atmospheric Environment

Atmospheric Environment

The Science of The Total Environment

Atmospheric Environment

Chemosphere

Atmospheric Environment

Atmospheric Environment

Atmospheric Environment (Part A)

Atmospheric Environment

Atmospheric Environment

Atmospheric Environment

Atmospheric Environment

Characteristics of organic and elemental carbon in PM_2.5 samples in Shanghai, China

Levels of PM_2.5, OC and EC in Shanghai