北京PM2.5颗粒物中有机碳和元素碳的时空分布及来源分析

Analytical method
He/10%O2 1/8 of each sample 450℃ 1/8 of each sample He/10%O2 CO2 950℃ EC=TC-OC CO2 TCD TCD OC TC
Data Quality Control
Organic carbon contents of standard samples determined with an element analyzer at 450C

Second origin(submicron particles)

Gas to particle conversations of volatile organic compounds Condensation of low vapor pressure volatile organics
c
OC/EC 6.3 4.0 7.4 3.2 2.6 1.6 2.5 2.2 3.8 4.8 2.2 3.5 3.5 11.6
ຫໍສະໝຸດ Baidu
8 104.1± 45.1 3 121.7± 55.0 9 257.6± 85.8 10 99.4± 33.9 10 86.7± 30.3 10 86.8± 29.6 30 91.1± 30.9
c
29.8± 11.7 10.4± 5.0 29.0± 13.3 8.8± 6.2 22.0± 6.1 12.4± 4.3 26.7± 11.0 10.6± 5.4 24.0± 15.3 7.7± 2.0 23.7± 9.4 9.0± 8.2
28 168.8± 114.1 36.7± 19.4 15.2± 11.1 23.1
OC:

primary origin

emitted directly from combustion of fossil fuels and biomass Emissions of plant spores and pollen, vegetation debris, tire rubber and soil organics (coarse particles)
OC, EC and TC Concentrations at five sites
Period Jul.-Aug., 2001 Dec., 2001 Jun.-Jul., 2002
Site BNU Pinggu BNU Miyun BNU CS YH
BJ urban
b
N
a
Average Concentration (μ g m-3 ) PM2.5 OC 17.1± 4.1 10.3± 1.9 EC 4.9± 5.4 4.5± 3.3 SOC 10.4 6.3
Sources of OC and EC
EC : a good indicator of primary anthropogenic pollutants


primary origin------emitted directly from combustion of fossil fuels and biomass
c
Average Mass percentage (%) OC 19.3± 9.2 9.7± 5.1 16.6± 7.7 12.6± 7.1 12.1± 3.4 10.9± 1.9 13.6± 4.0 12.2± 3.3 EC 4.1± 2.8 3.7± 2.8 6.1± 4.9 5.2± 1.6 7.6± 2.3 5.8± 3.1 6.2± 2.5 TC 23.4± 7.8 13.4± 4.4 18.7± 10.6 17.3± 3.5 18.4± 3.3 19.4± 3.7 18.4± 3.5 40.2± 12.3 37.7± 18.3 34.4± 5.6 37.2± 12.7 31.7± 13.7 32.6± 7.0 SOC/OC 59 57 45 57 57 37 50 48 64 72 43 59 58 59
41.2± 20.8 31.6± 31.0 17.2 11.5± 3.8 9.3± 3.3 11.2± 3.6 10.7± 3.6 5.2± 2.4 6.6± 3.2 5.3± 3.1 5.7± 2.9 6.8 3.4 5.8 5.3 27.5
11.3± 10.9 28.0± 15.5
5 683.1± 233.5 72.6± 24.5 37.0± 29.2 39.4
Outline
Introduction for carbonaceous species Sampling and analysis Spatial and temporal variations of OC and EC Estimations of second organic carbon Possible sources for OC and EC
1
Pure caffeine Pure calcium carbonate Pure graphite Mixture I 49.48 11.62 99.35 45.23
2
49.43 11.78 97.49 44.9
3
49.48 11.74 99.75 45.5 49.46 11.71 98.86 45.2 0.06 0.71 1.22 0.7 -0.03 -2.39 -1.14 0.22
The Characteristics of carbonaceous species in PM2.5 in Beijing
Mo Dan
Guoshun Zhuang
The Center for Atmospheric Environmental Study, Beijing Normal University, P.R.China 100875
Literature values for OC and EC concentrations from various location
Location Beijing, Chinaa Period 6-7/2002 12/2002 Kaohsiung,Taiwana Los Angeles, USAa 11/1998-4/1999 6-9/1987 11-12/1987 Beijing,Chinaa Seoul, Koreaa Soeul, Koreaa Kwangju, Koreab Nairobi, Kenyaa Meru, Kenyab PolyU, HongKonga HT, HongKongb 6/1999-6/2000 6/1994 11/27–12/09/99 06/07–06/2 0/00 3/2000 5-6/1999 11/2000-2/2001 11/2000-2/2001 Conc. (μgm－3) OC 10.7±3.6 36.7±19.4 10.4 8.3 18.5 29.1 9.95 15.2±9.9 7.6±3.7 13±3 6±1 9.45±2.01 5.52±1.13 EC 5.7±2.9 15.2±11.1 4 2.4 7.3 10.1 7.57 7.3±5.9 4.9±2.1 2.3±0.3 1.4±0.1 5.80±1.14 1.36±0.40 18.18 13.04 11.16 3.22 2.4 1.5 5.7 4.3 Mass Percentage (%) OC 12.2±3.3 26.7±11.0 15.3 EC 6.2±2.5 10.6±5.4 5.9 OC/EC 2.2 3.5 2.6 References this study this study J.J. Lin et al. (2001) Chow et al. (1994) Chow et al. (1995) K. He et al. (2001) Kim et al. (1999) Park et al. (2002) Park et al. (2003) Gatari (2003) Gatari (2003) Ho et al. (2002) Ho et al. (2002)
Mar., 2003
a
BNU Miyun
b
Numbers of samples
BJ urban includes three sites of BNU, CS and YH
SOC represents secondary organic carbon
120
100
Concentration(μg/m3)
Standard sample 1 Pure caffeine Pure calcium carbonate Pure graphite Mixture I a 49.59 0 0 20.62 Parallel runs, % 2 49.39 0 0 20.25 3 49.57 0 0 20.53 49.52 0 0 20.47 0.22 0 0 0.94 49.48 --20.57 0.07 ---0.5 Arithmetic average, % RSD, % Theoretical carbon content, % Relative error, %
Measured precise for real samples
Temperature ,¡ æ) Sample Mass of loaded particulate, mg Fraction of filters taken for C analyses Parallel runs No. 1 C, % 0.235 Arithmetic average, % RSD ,% 450 (OC) Sample 1 13.18 1/16 No. 2 0.255 No. 3 0.257 0.260 6.9048 No. 4 0.266 No. 5 0.285 No. 1 0.233 950 (TC) Sample 2 9 1/8 No. 2 0.230 0.234 1.937 No. 3 0.238
Miyun County remote site
Pinggu County remote site Shijingshan
Capital Steel Plant
industrial site
Beijing Normal University traffic site
South-Fourth-Cycle Rd. Residential site
Total carbon contents of standard samples determined with an element analyzer at 950C
Standard sample Parallel runs, % Arithmetic average, % RSD, % Theoretical carbon content, % 49.48 12 100 45.1 Relative error, %

Why to study carbonaceous particles



Carbonaceous species were found to contribute significantly to fine particle (20%-40% of fine particle, even up to 80%, in urban and industrialized areas) EC is the dominant light absorbing species and it also is the carrier for gas-to-particle reactions of SO2, NOx. Many organic compounds such as PAHs, PCBs and PCDFs are potential mutagens or carcinogens and pose significant human health risk.
80
60
OC-sum OC-win OC-spring EC-sun EC-win
40
20
0
N= 181818181818 101010101010 5 5 5 5 5 5 3 3 3 3 3 3 1010101010 10
EC-spring BNU CS Miyun Pinggu Yihai
SITE
Dec., 2002
BNU CS YH
BJ urban
b
9 151.4± 126.8 36.6± 26.2 12.9± 10.4 24.9 10 171.7± 141.7 36.0± 21.5 9.8± 6.7 9 180.0± 77.9 3 80.2± 80.2 5 76.1± 53.4 37.5± 11.2 21.9± 12.1 17.7 12.6± 5.8 15.5± 6.5 7.2± 8.5 7.9± 7.9 6.1 8.9