Concentration and chemical composition of PM2.5 in Shanghai for a 1-year period
Introduction
Air quality is an important issue in China and the Chinese government is committed to improving it by establishing more stringent emission control strategies. Particulate matter is a primary concern due to its possible health impacts and visibility degradation. China has a PM10 standard, but does not have one for PM2.5. Thus, relatively little data is available concerning PM2.5 concentrations and trends. In 1999, we initiated a PM2.5 monitoring program in Beijing and Shanghai that included chemical characterization of the collected PM. Results from the first year of monitoring in Beijing have been reported (He et al., 2001). This paper examines the results from 1 year of monitoring in Shanghai.
Shanghai is the largest city of the Shanghai Municipality, which has over 15 million people. It is located at the mouth of the Yangtze river in Jiangsu province and is one of the worlds’ largest seaports. It has a strong commercial and industrial base with China's largest petrochemical complex, its largest steel output, and other major industries. Years of rapid economic growth and urban development have burdened its air quality, resulting in visibility reduction and public health concerns (Ye et al., 1999; Brunekreef and Dockery, 1995; He et al., 1993; Shen et al., 1992; Yan, 1989). In addition to local air quality problems, there are also regional concerns. For example, the impact of atmospheric haze on agriculture due to reduced sunlight was assessed for the lower Yangtze basin with an estimated 5–30% reduction in crop yields (Chameides et al., 1999). Xu (2001) suggested that the “northern drought with summer flooding”—a recent climatic change phenomenon in China during the last 20 years may be attributable to increases in sulfur dioxide emissions from the industrialization of east China. Despite these serious concerns, there is little published data on atmospheric PM concentration, composition, and sources. Song and Cui (1996) did make total suspended particles (TSP) and SO2 measurements in Shanghai and four other cities in China under a UNEP-WHO environmental program over a 12-year period. It was observed that the TSP mass concentration was in the 100–300 μg/m3 range with the highest concentration in the winter. Recently, Davis and Guo (2000) measured PM10 in Shanghai on two separate days and reported the mean geometric particle diameters to be 1.2 and 1.6 μm.
Increased energy consumption from the 1980s to the early 1990s has contributed to the increasing ambient aerosol concentration in Shanghai. According to Tong and Xi (1995), more than 80% of the energy in Shanghai was from low quality coal. The industrial consumption of coal was expected to rise from 19.6 million tons in 1989 to 41.7 million tons in 2000. Further examination of the SO2 emissions led them to suggest that energy consumption has to shift from the use of coal for power generation to lower sulfur fuel oil or natural gas to improve air quality. Chang et al. (1998) modeled the air quality in Jiangsu province and concluded that the atmospheric SO2 burden represented a significant health risk to Shanghai. Flue-gas desulfurization (FGD) for power plants and other large coal users was recommended as one key strategy to manage air quality in the region. Similar findings and conclusions were documented by Song and Cui (1996) who reported annual average concentrations of TSP and SO2 in Shanghai and four other Chinese cities in a 12-year study from 1981 to 1992. More recently, Streets et al. (1999) emphasized the need to deploy advanced technology to control SO2 emissions from stationary sources. They concluded that without additional controls much of the population will be exposed to SO2 and sulfate ambient concentrations in excess of World Health Organization guidelines.
There is also concern over mobile source emissions. Ye et al. (1999) noted that mobile sources are increasing rapidly in China and that there are approximately 700,000 cars and 500,000 scooters on the streets of Shanghai. Zhou and Ye (1998) also collected particulate emissions from diesel engines, 2-stroke motorcycles and scooters and reported on the short-term mutagenic activities of the extracts. Meanwhile, Ji et al. (1993) estimated that 12,300 tons of road dusts were re-entrained into the ambient air in Shanghai annually, which is about 8% of the stationary source inventory. It is expected that continued urban development will cause further increases in population and traffic density for the next 30 years.
The purpose of this work was to conduct weekly monitoring of PM2.5 to examine seasonal variations in the PM2.5 and gases, and to determine the composition of the PM in an effort to better understand its sources.
Section snippets
Experimental
Sampling was conducted at two sites, one on the rooftop of the Environmental Engineering Building on the campus of Tongji University. The other site was at a Shanghai Environmental Protection Bureau rooftop air quality monitoring station on Hainan Road, which is closer to downtown than the University site. The Tongji site was 16 m above the ground while that at the Hainan Road site was 18 m above the ground. Both sites were approximately 50 m from major roads. The distance between the two sites is
Ambient concentrations
The site-to-site comparison of the weekly average PM2.5 mass concentration is shown in Fig. 1. There is generally good agreement between the two sites. A linear regression between the mass at the two sites had an R2 of 0.94 and a slope of 0.95. This suggests that there were no significant proximate sources and both sites represent an urban aerosol. The annual average PM2.5 at Tongji was 63.4 μg/m3 for the entire sampling period. Weekly PM2.5 averages ranged from 19.9 to 156 μg/m3. For the May
Summary and conclusions
Ambient PM2.5 mass concentrations were monitored in Shanghai for 52 consecutive weeks for the first time. The annual average concentrations were 57.9 and 61.4 μg/m3 at the two sampling sites, with a range from 21 μg/m3 in the summer to 147 μg/m3 in the winter. The bulk composition of the PM2.5 mass was determined, with good overall mass balance. The most abundant species contributing to the PM2.5 mass were organic carbon, sulfate, elemental carbon, ammonium, nitrate, silicon, potassium, iron,
Acknowledgements
This study was funded by General Motors. We would like to thank Yun Yan and Diana Yao from the GM China Office for their help in handling samples and interfacing with the participants.
References (29)
- et al.
Air quality impacts as a result of changes in energy use in China's Jiangsu province
Atmospheric Environment
(1998) - et al.
The DRI thermal/optical reflectance carbon analysis systemdescription, evaluation and applications in US air quality studies
Atmospheric Environment
(1993) - et al.
Airborne particulate study in five cities of China
Atmospheric Environment
(2000) - et al.
The characteristics of PM2.5 in Beijing, China
Atmospheric Environment
(2001) Long-range transport of Yellow Sand to Taiwan in spring 2000observed evidence and simulation
Atmospheric Environment
(2001)- et al.
Influence of mineral matter on biomass pyrolysis characteristics
Fuel
(1995) Abrupt change of the mid-summer climate in central east China by the influence of atmospheric pollution
Atmospheric Environment
(2001)- et al.
The water-soluble ionic composition of PM2.5 in Shanghai and Beijing, China
Atmospheric Environment
(2002) Epidemiologic studies of chronic respiratory diseases in some regions of China
Chest
(1989)- et al.
Effects of two new lubricants on the mutagenicity of scooter exhaust particulate matter
Mutation Research
(1998)
Relationships among aerosol constituents from Asia and the North Pacific during PEM-west A
Journal of Geophysical Research
Epidemiological studies of short-term effects of low levels of major ambient air pollution components
Environmental Health Perspectives
Aerosol composition at Cheju island, Korea
Journal of Geophysical Research
Cited by (499)
Long-term PM<inf>2.5</inf> pollution over China: Identification of PM<inf>2.5</inf> pollution hotspots and source contributions
2023, Science of the Total EnvironmentImpact of changes in refractive indices of secondary organic aerosols on precipitation over China during 1980–2019
2023, Atmospheric EnvironmentAccuracy assessment of CAMS and MERRA-2 reanalysis PM<inf>2.5</inf> and PM<inf>10</inf> concentrations over China
2022, Atmospheric Environment