Detecting the Heavy Metal Concentration of PM2.5 in Beijing Research Background Clean air is a basic health requirement for every human being. However, air pollution across the globe is constantly threatening human health.1 On December 18, 2012, Greenpeace and the Public Health Faculty of Peking University jointly issued the report Dangerous Breathing, PM2.5: Measuring the Human Health and Economic Impacts on China's Largest Cities, which found that PM2.5 (particles with an aerodynamic diameter less than 2.5μm) pollution has caused extensive damage to public health. Under existing air quality conditions, the total number of premature deaths in the four cities of Beijing, Shanghai, Guangzhou and Xi’an in 2012 would be 8,572, and the economic loss caused by these deaths would reach 6.8 billion RMB. PM2.5 is prone to absorb hazardous substances, and is a major issue currently endangering Chinese public health. PM2.5 from different sources has different compositions and various impacts on health. In China, the concentration monitoring of PM2.5 has just begun, and discussions of PM2.5 sources and how to control it is also at a primary stage. This research focuses on heavy metal contamination of PM2.5 and the relevant individual exposure risks. Toxicology experiments have proven that metal elements are possible components of health hazards in air particles.2 Compared to PM10, PM2.5 is more capable of carrying heavy metals, and is therefore more hazardous to human health.3 Based on this observation, we hope more consideration will be given to the hazardous substance constituents carried by PM2.5 and how it should be dealt with when we talk about PM2.5 control. From December 3, 2012 to January 18, 2013, Beijing experienced the most severe episode of air pollution since PM2.5 monitoring data became available. In this period, Greenpeace carried out monitoring of individual PM2.5 exposure to nine volunteers in the Beijing area using individual samplers (with a duration of 22 days and 42 samples), and also entrusted the Public Health Faculty of Peking University to monitor PM2.5 in the air (for 15 days) on the 6th floor platform of their building. A series of detection and analysis tests were carried out, as well as on the samples from individuals. Main Conclusions Analysis of heavy metal concentrations in the air show the concentration of arsenic in PM2.5 is above the norm. This alarming fact deserves greater attention from the Municipal Government of Beijing and Ministry of Environmental Protection of the People’s Republic of China. During the detection period, the average daily concentration median of heavy metal arsenic in Beijing's PM2.5 was 23.08 Ng /m3. 4 According to Ambient Air Quality Standards issued in February 2012, the annual mean reference concentration limit value is 6 Ng /m3, meaning the concentration detected during the course of this research is 3.85 times the limit value. During heavy pollution days, the concentration median reached 34.68 Ng /m3,5 and the highest average daily concentration during this period reached 70.91 Ng /m3. During the 15 detection days, there were 12 days in which arsenic concentration rose above the annual mean reference limit value taken from Ambient Air Quality Standard, four days in which cadmium 1
concentration rose above the annual limit value, and two days in which lead concentration rose above the limit value. During the 22 day detection period, the median individual arsenic exposure concentration of the nine volunteers was 12.13 Ng /m3. During heavy pollution days, the median of individual arsenic exposure average daily concentration was 24 Ng /m3. On December 19, the arsenic exposure average daily concentration median for one of the volunteers sat at 58.87 Ng /m3. Among the 42 person-times detection, the individual arsenic exposure concentration of 29 person times is above the annual mean reference limit value. 1 http://apps.who.int/iris/bitstream/10665/69477/3/WHO_SDE_PHE_OEH_06.02_chi.pdf 2 Research Progress on PM2.5 in Environmental Air, Xiao Mei, Guo Lin, and He Zongjian 3 Different Particles Pollution and Their Heavy Metal Distribution Situation in Heating Period, Lin Zhiqing, Environment and Health Magzine, 2005, 22(1):33-34 4 Arithmetic average value is 23.18 Ng /m3 5 Arithmetic average value is 41.62 Ng /m3 Compared to previous research6 7 8 9, the arsenic concentration of PM2.5 in Beijing is constantly at a high level. And while the levels of this period are lower than previous, it is still significantly higher than other international cities.
Los Angeles
Birmingham
Beijing 2012-2013
Literature Greenpeace sampling
Beijing 2007
Beijing 2000 0 5 10 15 20 25 30 35 40 45 50
Heavy Metal Concentration Detection Results of PM2.5 from Ambient Air and Individual Inhaling in Beijing (1) Ambient air Detection background: During the 15 day testing period from December 3, 2012 to January 18, 2013, there were four days in which the air quality was excellent, six days which had mild or moderate pollution, and five days that saw severe pollution. The sampling site was on the 6th floor platform of the Public Health Faculty of Peking University, which is near the Third Hospital of Peking University.
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6 The Research on Chemical Elements Contents Variety in PM10 and PM2.5 during the Dust and Sand Weather in Beijing and Alashan League [J]. Wang Wei, Tao Hui, and Dae-Seon Kim, etc. Environment and Health Magazine, 2010 (9): 763-766 7 Song Y, Xie S, Zhang Y, et al. Source apportionment of PM2.5 in Beijing using principal component analysis/absolute principal component scores and UNMIX [J]. Sci Total Environ, 2006, 372 (1): 278-286. 8 Chow JC, Watson JG, Fujita EM, Lu ZQ, Lawson DR, Ashbaugh LL.Temporal and spatial variations of PM2.5 and PM10 aerosol in the Southern California Air Quality Study. Atmos Environ 1994; 28 (12): 2061–80. 9 Harrison et al. (199)
Heavy Metal
Detection results in this research （Ng/m3）
Detection results during heavy pollution days （Ng /m3）
Days in which the heavy metal concentration of PM2.5 was above the relevant reference annual mean concentration limit value in ambient air
Arsenic Lead Cadmium
23.08 244.10 4.20
34.68 312.43 6.68
12/15 2/15 4/15
Ambient Air Quality Standard of China (annual mean value, Ng /m3)
6 500 5
European World Health Union 11 Organization10 (annual (annual mean mean value, value, Ng /m3) Ng /m3)
500
6 500 5
(2) Individual inhaling Previous research into the exposure concentration levels of PM2.5 and the heavy metal exposure concentration of PM2.5 usually include data from outdoors stationary sites. However, in urban environments people will spend over 80% of their time indoors. To achieve an authentic level of exposure concentration of PM2.5 and the heavy metal concentration of PM2.5 by individuals with different behavior patterns, we carried out testing from December 3, 2012 to January 19, 2013. This was overseen by Greenpeace, with the Public Health Faculty of Peking University carrying out sampling, detecting and analysis on samples from nine volunteers living in Beijing and using personal PM2.5 samplers. The results were as follows: Individual PM2.5 detection in the Beijing area: arsenic content and proportion of days in which arsenic content was over the national standard 3
PM2.5 arithmeti c mean value
PM2.5 media n
100%
209.61
209.61
Arithmeti c mean value (Ng/m3)
Median (Ng/m3 )
2
35.95
35.95
5
29.66
22.9
4
80%
81.19
65
5
14.68
14.17
4
80%
116.46
123.76
5 5
14.29 13.95
16.08 12.64
4 4
80% 80%
105.21 112.85
100.87 117.64
5
11.62
4.26
2
40%
132.95
138.65
5 5
9.43 7.98
6.34 7.3
3 3
60% 60%
32.34 105.15
5
6.91
6.01
3
60%
38.23 121.61 55.74
Occupation of Samplin the volunteers g days
Singer Software engineer Outdoor sports participant Managers Office worker Private enterprise owner Child Taxi driver NGO employee
Proportio n of days in which arsenic content was above the national standard (%)
Days in which arsenic content was above the national standar d 2
56.52
10 Bai X P, Li H, Fang D, et al. [Application research of data assimilation in air pollution numerical prediction] [J]. Huan Jing Ke Xue, 2008, 29(2): 283-289.11 PAN Xiaochuan, the Public Health Academy of Peking University 11 The Method Of Formulating Quality Standard Relating To Several Pollutants In Ambient Air In EC [J] HU Bi-bin ENVIRONMENTAL SCIENCE AND MANAGEMENT Hazards to Health due to Heavy Metal in PM2.5 (1)
Intake methods:
PM2.5 can carry many heavy metals.12 Breathing is one of two primary channels for heavy metals to enter the human body; another is via drinking water and consuming food. (2)
Accumulating health effects:
Heavy metals tend to bio-accumulate in organisms. Once they enter the bodies of animals, it is difficult for 4
them to be discharged and can lead to disease. (3)
Health impacts:
Arsenic: The International Agency for Research on Cancer and World Health Organization has declared arsenic a human carcinogen since 1981. The Agency for Toxic Substances and Disease Registry lists arsenic as the number one hazardous substance to human health. Intake of arsenic may cause nervous system damage, cardiovascular disease and urethral carcinoma. Breathing in and touching arsenic may cause both lung cancer and skin cancer. Lead: Lead is harmful to the nervous system, digestive system, hematopoietic system, urinary system, cardiovascular system, immune system, and endocrine system. Nor does lead exposure have a safety threshold (note: even micro-scale ingestion is harmful for health), especially for children. Cadmium: Cadmium may cause kidney and bone damage. Constant exposure may increase risk of cancer. Other research shows a correlation between metal components in PM2.5 air pollution and rising blood  pressure of healthy adults in the Beijing area. Results indicate arsenic present leads to a positive correlation with systolic pressure and diastolic pressure.14 Chronic exposure to arsenic and lead is also related to blood pressure rising.15 An analysis was conducted of the relation between concentration of metal elements and PEFR (Peak  Expiratory Flow Rate) in school-age children living in Beijing and Alashan League of Inner Mongolia in China and Seoul, Korea. Testing was conducted during sandstorm season, with researchers Hong Y.C., Pan Xiaochuan and others finding a statistical correlation between arsenic, lead, cadmium in PM2.5 and the decline of PEFR.16 (4)
Susceptible population:
According to the research, reactions to harmful factors in environment vary greatly among the population. While environmental pollutants will generally lead to an increase of physiological load or physiological changes in the population, there are a few who must also suffer bodily function disorders, poisoning, and even death. This group has above-average sensitivity and is called the "susceptible population". Compared to the general population, harmful health effects will appear at much lower exposure levels, or with higher incidents of illness, or with reactions that are much stronger. Children, the elderly, pregnant women and patients with severe chronic diseases belong to the susceptible population and often need to pay more attention to self-protection. 12 http://www.ec.gc.ca/air/default.asp?lang=En&n=BEC329C4-1 13 Public Health Academy of Peking University, PAN Xiaochuan 14 Wu S, Deng F, Huang J, et al. Blood pressure changes and chemical constituents of particulate air pollution: results from the healthy volunteer natural relocation (HVNR) study [J]. Environ Health Perspect, 2013, 121 (1): 66-72. 15 Mordukhovich I, Wright R O, Hu H, et al. Associations of toenail arsenic, cadmium, mercury, manganese, and lead with blood pressure in the normative aging study [J]. Environ Health Perspect, 2012, 120 (1): 98-104. 16 Hong Y C, Pan X C, Kim S Y, et al. Asian Dust Storm and pulmonary function of school children in Seoul [J]. Sci Total Environ, 2010, 408 (4): 754-759. 5
Arsenic Pollution Source Analysis of PM2.5 and Policy Suggestions (1)
Arsenic source analysis of PM2.5
Emission of coal combustion is a major source of arsenic found in the air. According to research, around one third of arsenic in coal volatilizes directly into the air. 84.6% of total arsenic in coal at high concentrations of PM2.5 enter the atmosphere and can travel long distances, causing widespread pollution during the process of coal combustion.17 Many other studies have shown that smelting furnace18, fly ash19 and coal soot20 from coal combustion emission also increase arsenic concentrations of the air. Furthermore, some studies indicate that arsenic content is more than 1000mg/g of PM2.5 in emissions from coal-fired power plants, causing great harm to people’s health.21 With these test results in mind, Beijing Municipal Government and Ministry of Environmental Protection must pay greater attention to arsenic in PM2.5.
Figure 2-3 Diagram of the environmental migration of air pollution, caused by coal combustion and leading to human exposure. The words in the figure from left to right, from above to below then from left to right again are: spread to the air, particulate matters, heavy metal, settle, soil, water, food, through alimentary canal, through respiratory tract, fat-soluble substances through the skin mucus, and human body. Coal consumption of Beijing-Tianjin-Hebei region reached 384.2 million tons in 2011, with coal consumption in Hebei province alone more than 300 million tons. This accounts for 80% of the coal consumption in this region22 and even exceeds levels from Germany, the biggest economy in Europe. According to the China Environmental Statistical Yearbook (2012), three major pollutant emissions from Hebei province accounted for 77-90% of the total emissions in the Beijing-Tianjin-Hebei region. Due to the huge scale of energy consumption in Hebei province, the Beijing-Tianjin-Hebei region must control coal consumption and solve the problem of air pollution at a regional level. 17 Characterization of Arsenic Emissions from a Coal-Fired Power Plant, Guo Xin, Zheng Chuguang and Chen Dan 18 Pollution Characteristics and Research of PM2.5 in Beijing, Yang Fumo, Tsinghua University 19 The True Cost of Coal - the Coal Dust Storms along with Wind Hitting, Zhuang Guoshun, Fudan 6
University 20 Determination and Distributed Characteristics Research on Metal Elements in PM2.5s, Peng Xilong, He Zongjian and the others 21 Distribution and Enrichment of Heavy Metal Elements in Inhalable Particalate (PM10) Caused by Coal Combustion, Lu Jing, Sun Junmin, State Key Laboratory of Coal Resources and Safe Mining, China Mining University 22 China Energy Statistical Yearbook (2012) Air pollution problems in Beijing are a regional and cross-border problem. According to a study published in Atmospheric Chemistry and Physics Magazine, 39% of ingredients in PM2.5 in Beijing come, on average, from non-local emissions. The same study also found if wind blows continuously from the south into Beijing, non-locally produced air pollutants will account for 50-70% of PM2.5 in Beijing.23 To control air pollution, the Beijing Municipal Government has proposed to cut down coal consumption to 15 million tons in 2015.24 But coal consumption in Hebei province, near Beijing, continues to be in rapid expansion. In view of this present situation, we put forward the following four policy suggestions:
Coal Consumption Statistics of Beijing-Tianjin-Hebei Region 40000 35000 Ten thousand tonst
30000 25000 20000
Hebei Tianjin Beijing
15000 10000 5000 0 2000 2001 2002 2004 2005 2006 2007 2008 2009 2010
(2)
Policy suggestions According to the 12th Five-Year Plan of Atmospheric Pollution Prevention in Key Region approved by State Council in October 2012, the Ministry of Environmental Protection should publish a priority list for national toxic air pollutant control. They should also improve the relevant emission standards and technical control specifications for toxic air pollutants. Carry out toxic air pollutant monitoring in key areas and strengthen research into harmful material composition and sources of PM2.5 in various districts. Also, reduce the concentration level of PM2.5, along with bolstering harmful substance prevention and control in PM2.5, such as heavy metals. Strengthen research into the effect of arsenic on public health in relation to PM2.5. China's energy structure heavily relies on coal and the three areas of Beijing-Tianjin-Hebei, Yangtze River Delta and Pearl River Delta consume 40% of the country's coal consumption and yet occupy just 6.3% of the area. These three urban centers are the most densely populated areas in China. Prevention and control of relative atmospheric pollution sources in these areas has become urgent. Considering the regional dispersion of air pollution, conditions in the Beijing area can only be improved with regional cooperation in the Beijing-Tianjin-Hebei area. A coal consumption cap in this region must 7
be set up as soon as possible. If coal consumption of the Beijing-Tianjin-Hebei region cannot be controlled effectively, the air quality of the whole region will not see any obvious improvement. 23 Air quality during the 2008 Beijing Olympic Games, David G. et al, Atmospheric Environment 24 Work Plan for Speeding up Cutting down Coal Combustion and Promoting Air Quality Improvement, Beijing Municipal Government Appendices (Appendix 1) Experiment Method in the Concentration Detection of Individual Exposure to PM2.5 The concentration sampling of individual exposure to PM2.5 was made according to regulations set in GB 3095-2012 Ambient Air Quality Standard and HJ618-2011 Weight Determination of PM10 and PM2.5 in Ambient Air. It used a sampler that was capable of extracting rational volume air at a constant speed, trapping PM2.5 in the air to the filter membrane, and then using analytical balances to weigh the difference between the filter membrane before and after sampling. We were then able to calculate the average concentration of PM2.5 during the testing time. In this experiment, individual sampler components included a sampling head (PMI) and sampling pump (PCXR8 type, SKC of USA), which are connected by a hose. The sampling pump extracts air, with a flow rate of 3L/minute. Volunteers take the sampler with them, and it records sampling time automatically. The sampling head is fixed to the volunteer's shirt collar with a clamp (this area is close to the nose and mouth, that is, the "breathing zone"). The sampler filters out particles whose aerodynamic diameter are greater than 2.5 micron, and absorbing particulate matters whose aerodynamic diameter is less than or equal to 2.5 micron (PM2.5) on quartz filter membrane (SKC of USA).
Individual sampler of PM2.5 After sampling, the filter membranes before and after sampling are tested in a box with standardized temperature and humidity in order to prevent these factors from affecting the weight. A balance called XS105 (Mettler-Toledo Company, Switzerland), which has 0.00001 accuracy is then used to weigh the samples. The concentration of PM2.5 during sampling is the net weight divided by the volume in standard temperature and pressure (using the sampling volume to convert). In addition, portions of the metal compositions of PM2.5 were also analyzed. Fine particle samples of this study were analyzed using an Ultra WAVE type microwave digestion instrument (Milestone Company of 8
Italy) of Central Laboratory of Medical Science Department of Peking University. The concentration of Cr, Mn, As, Se, Ni, Cu, Zn, Cd, Hg and Pb of PM2.5 included in this study were determined by a DRC - II type inductively coupled plasma mass spectrometer (ICP-MS) of PE Company of USA. Parameters of the DRC - II type inductively coupled plasma mass spectrometer include: atomizing gas flow rate: 0.96 L/min; assisting gas flow rate: 1.80 L/min; plasma gas flow rate: 15.0 L/min; duration: 100 ms; quantity of sample improvement: 1 ml/min; scanning mode: single point jump peak; resolution: 0.7-0.9 aum. (Appendix 2) Experiment Method in the Metal Concentration Detection of PM2.5 in the Environment The stationary sampling site of PM2.5 was on a platform of the 6th floor of the teaching building of the Public Health Faculty of Peking University. The monitoring method of PM2.5 in the air and metal component detection method were the same as that used for monitoring individual exposure to PM2.5. (Appendix 3) Limitations of the Experiment 1. According to Ambient Air Quality Standard, the ambient monitoring objects of arsenic are arsenic in the air, but this experiment is detecting the concentrations of arsenic in PM2.5. 2. We have only used average annual value standards for some of the metals in ambient air, not average daily concentration standards at present in China. This study assumed the average daily value to be comparable with the average annual value standard, which will have some limitations in terms of interpretation of results.
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