atmospheric organic nitrogen deposition in china

at SciVerse ScienceDirect

Atmospheric Environment 46 (2012) 195e204

Contents lists available

Atmospheric Environment

journal homepage: www.elsevier .com/locate/atmosenv

Atmospheric organic nitrogen deposition in China

Y. Zhang a, L. Song a, X.J. Liu a,b,*, W.Q. Li c, S.H. Lü d, L.X. Zheng a, Z.C. Bai a, G.Y. Cai a, F.S. Zhang a

aCollege of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, ChinabKey Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, Chinac Fujian Institute of Tobacco Agricultural Sciences, Fuzhou 350003, Chinad Institute of Soil and Fertilizer, Sichuan Academy of Agricultural Sciences, Chengdu 610066, China

a r t i c l e i n f o

Article history:Received 13 May 2011Received in revised form25 August 2011Accepted 30 September 2011

Keywords:Atmospheric depositionDONDON/TDNRainfallSeasonal variation

* Corresponding author. Key Laboratory of BiogeogrLand, Xinjiang Institute of Ecology and Geography, CUrumqi 830011, China.

E-mail address: [email protected] (X.J. Liu).

1352-2310/$ e see front matter � 2011 Elsevier Ltd.doi:10.1016/j.atmosenv.2011.09.080

a b s t r a c t

Precipitation samples have been collected and analyzed for organic and inorganic nitrogen (N) at 32 sitesin China from 2005 to 2009. Our results suggest that dissolved organic nitrogen (DON) accounts for 28%of the total atmosphere bulk N deposition. Average annual DON deposition was 6.84 kg N ha�1 yr�1,ranging from 1.01 to 19.7 kg N ha�1 yr�1. The volume weighted average DON concentration was77 mmol L�1, ranging from 13 to 190 mmol L�1, which was much higher than results obtained in otherregions of the world. Analysis of seasonal variations of DON concentration, deposition, the ratio of DONto total dissolved N (TDN), rainfall and wind frequency roses revealed possible pollution sources inspecific regions, e.g. agriculture, oceanic spray and re-suspension. Significant correlations of DON withTDN from results in this study and elsewhere indicate that atmospheric organic N species have similaranthropogenic pollution sources to atmospheric inorganic N species, and that DON deposition is animportant part of the TDN deposition.

� 2011 Elsevier Ltd. All rights reserved.

1. Introduction

Atmospheric N deposition has received increasing attentionbecause of its acidification and eutrophication impacts on bothterrestrial and aquatic ecosystems (Duce et al., 2008; Bobbink et al.,2010). However, most research has concentrated on inorganicN deposition and its biogeochemical cycling. Much less informationis available for organic N deposition, both its abundance andorigins, because of the difficulty in storage, transport and chemicalanalysis (Bronk et al., 2000; Cornell et al., 2003; Vandenbruwaneet al., 2007). Recently, interest in dissolved organic N (DON)deposition has increased because of its increasingly apparentsignificant contribution (w30%) to total atmospheric N deposition(Cape et al., 2004; Neff et al., 2002; Cornell, 2011). Also, it has beenshown that the bioavailability of deposited DON is much the sameas that of inorganic N, especially for N-poor systems (Näsholm et al.,1998; Bronk et al., 2007; Violaki et al., 2010).

Currently, the most widely employed method for estimatingDON concentration is the difference between TDN and dissolvedinorganic nitrogen (DIN) (i.e. ammonium and nitrate), whichresults in a large uncertainty for DON as the sum of the

aphy and Bioresource in Aridhinese Academy of Sciences,

All rights reserved.

uncertainties of TDN, ammonium and nitrate. In addition, there hasbeen no universally recognized oxidation method for convertingDON to TDN. Persulfate oxidation (PO), ultraviolet (UV) and hightemperature oxidation (HTO) methods are commonly used, but it isstill impossible to evaluate the oxidation efficiency of all thesemethods from the different results (Cornell and Jickells, 1999;Bronk et al., 2000; Vandenbruwane et al., 2007). Scudlard et al.(1998) compared the oxidation efficiency of PO and UV methodsand suggested that PO gave a higher recovery than UV. Conversely,Cornell and Jickells (1999) made a similar comparison, butproduced the opposite result. Bronk et al. (2000) compared therecoveries of the three methods and found PO yielded the highestrecovery while UV produced the lowest recovery and was highlyunpredictable. Cape et al. (2001) and Rogora et al. (2006) found thatHTO gave a slightly higher recovery than the other methods. Morerecent studies found that PO was more reliable than HTO (Doyleet al., 2004; Sharp et al., 2004; Vandenbruwane et al., 2007).However, if used properly, all the methods will have good recov-eries, and the differences reported are rather small.

In 2008, our group reported initial results for DON depositionand its anthropogenic sources in China (Zhang et al., 2008a).However, there were some uncertainties due to the short-termnature of the monitoring and the relatively few sites. In thecurrent study, DON in precipitation was measured at 32 sites for5 years in different regions across China. This therefore presentsa more comprehensive assessment of atmospheric N deposition.

mailto:[email protected]

www.sciencedirect.com/science/journal/13522310

www.elsevier.com/locate/atmosenv

http://dx.doi.org/10.1016/j.atmosenv.2011.09.080



Y. Zhang et al. / Atmospheric Environment 46 (2012) 195e204196

Persulphate Oxidation was used to convert DON to TDN, and theoxidation efficiency was determined in a pre-experiment. Thespatial and seasonal variations, together with the meteorologicalconditions were used to provide a better understanding of thepotential origins of atmospheric organic N. Our research hasallowed us to make more complete analyses of the importance ofDON in atmospheric N deposition and of its biogeochemical cyclingin different ecosystems.

2. Material and method

2.1. Experimental sites

Monitoring was carried out at 32 sites in different regions andecosystems in China. The first sampling was started at Fenghua inDecember 2004 with increasing numbers of sites from then. Mostof the 32 sites have been monitored since January 2007. Details,including the sampling duration, for all the sites are listed in Table 1and geographical distribution of the sites is mapped in Fig. 1.

Sites 1 to 13 are located in the North China Plain (NCP), anintensive agricultural region with very high N fertilizer use onfarmland (over 500 kg N ha�1 yr�1 applied to cropland and morethan 4000 kg N ha�1 yr�1 applied to greenhouse vegetables(Guo et al., 2010)). It is one of the areas for high atmospheric Ndeposition in the world and for the intensive anthropogenicemission of nitrogenous pollutants (Galloway et al., 2004). Sites 14to 17 are located in typical arid regions (Arid) in China with annualprecipitation less than 200 mm. Sites 14 and 15 are located in the

Table 1Details and sampling duration of monitoring.

Region No. Monitoring Site Longitude

NCP 1 CAU (China AgriculturalUniversity)

116.28

2 DBW (Dongbeiwang) 116.29

3 BAAFS (Beijing Academy ofAgriculture and ForestryScience)

116.29

4 BLZ (Beilangzhong) 116.555 SZ (Shuangzhuang) 116.206 CP (Changping) 116.237 FS (Fangshan) 116.148 SL (Shunyi-Liangxiang) 115.739 SY (Shunyi-Yanhe) 116.68

10 HM (Huimin) 117.5311 QZ (Quzhou) 114.9412 WQ (Wuqiao) 116.4013 BD (Baoding) 115.48

Arid 14 GY (Guyuan) 115.6915 DU (Duolun) 116.4916 UR (Urmqi) 87.62

17 WW (Wuwei) 102.61SC 18 WJ (Wenjing) 103.85

19 JY (Jianyang) 104.5520 CD (Chengdu) 104.06

KM 21 DC (Dianchi) 102.64

22 KY (Kunyang) 102.7323 YAU (Yunnan

Agricultural University)102.75

Coastal 24 DA (Dalian) 121.5825 QD (Qingdao) 120.3726 FH (Fenghua) 121.5327 FZ (Fuzhou) 119.57

FJ 28 SH (Shanghang) 116.4229 TN (Taining) 117.0130 LY (Longyan) 116.92

Forest 31 WYS (Wuyishan) 117.7532 LZ (Linzhi) 94.36

InnerMongolia steppe, natural grassland without fertilization. Sites16 and 17 are located in farmland, but N fertilizer use is not as highas at the NCP. Sites 18 to 20 are located in the Chengdu Plain (SC), tothewest of the Sichuan Basin, surrounded byHengduanMountains,Ta-ba Mountains and Wuling Mountains. It is a typical agriculturalarea in the southwest of China with the surrounding mountainscovered by natural forest. Sites 21 to 23 are located in the suburbs ofKunming (KM), a city characterized by flowers and vegetableproduction. A lot of organic fertilizer is applied to farmland in thisarea rather than chemical fertilizer, which has caused seriousentrophication of Dianchi Lake, to the south of the Kunming city.The other three sides of these sites are surrounded by mountainscovered by natural forests. Sites 24 to 27 are located in coastal ruralareas. Sites 28 to 31 are located in the Wuyi mountains (FJ). Site 31,Wuyishan, is located in a forest, while the other three sites arelocated in areas with tea tree fields. Site 32 is located in the forestecosystems in the Tibetan Plateau, the roof of the world anda remote area without anthropogenic influence.

2.2. Sample collection

Rain gauges (SDM6, Tianjin Weather Equipment Inc., China)were installed at all monitoring sites for the collection of precipi-tation. They were located in flat and open areas withoutsurrounding obstacles. The ground around the gauges was coveredby vegetations and the top of gauges was 1.2e1.5 m above thecanopy of the vegetation to avoid collection of resuspended dustand particulates. All the samples were collected immediately after

Latitude Sampling Duration Ecosystem

40.02 May, 2005eNov, 2009 Suburbanresidential area

40.04 Feb, 2005eOct, 2008 Suburban areawith farmland

39.94 May, 2006eSep, 2007 Urban

40.21 Jun, 2009eOct, 2009 Husbandry40.11 Jun, 2007eNov, 2009 Farmland40.22 May, 2005eOct, 2006 Farmland39.75 Apr, 2007eNov, 2009 Farmland40.11 May, 2005eNov, 2009 Husbandry40.07 May, 2007eNov, 2009 Weather station37.49 Oct, 2005eOct, 2009 Farmland36.78 May, 2005eOct, 2009 Farmland37.63 May, 2005eOct, 2009 Farmland38.85 Oct, 2005eAug, 2009 Farmland41.67 Dec, 2008eDec, 2009 Steppe42.20 Aug, 2007eDec, 2009 Steppe43.83 Mar, 2006eMay, 2009 Farmland in

steppe area37.96 Mar, 2007eOct, 2007 Farmland30.69 Jan, 2007eDec, 2007 Farmland30.39 Jan, 2007eOct, 2007 Farmland30.66 Jun, 2007eOct, 2007 Farmland25.00 Apr, 2009eNov, 2009 Vegetable field near

a eutrophied lake25.04 Apr, 2009eSep, 2009 Vegetable field25.13 Apr, 2009eDec, 2009 Suburban

38.89 Feb, 2006eOct, 2009 Costal36.19 May, 2006eDec, 2009 Costal29.61 Dec, 2004eSep, 2009 Costal26.06 Jan, 2009eDec, 2009 Costal25.05 Jan, 2009eDec, 2009 Tea tree field26.94 Dec, 2008eDec, 2009 Tea tree field25.15 Jan, 2009eDec, 2009 Tea tree field27.80 Jan, 2009eDec, 2009 Forest29.65 Jun, 2005eNov, 2009 Remote area with forest

Fig. 1. Distribution of the monitoring sites across China.

Y. Zhang et al. / Atmospheric Environment 46 (2012) 195e204 197

each rain event and sterilized with chloroform (1 ml CH3Cl per litersample) to inhibit chemical degradation by microbes. They werethoroughly mixed and stored in plastic bottles (50 ml), then frozenunfiltered until chemical analysis within three months. Rain gaugeswere cleaned with deionized water after each sample collection.

2.3. Persulfate oxidation methodology

To insure the feasibility of the methodology, the efficiency ofthe POmethod was tested before precipitation sample analysis, butunder real precipitation conditions. Most of the tests for recoverywere conducted using only one N-containing compound. However,real precipitation is much more complex and so complex chemicalinteractions exist in the environmental samples. Also, the Nconcentrations of precipitation in east and central China weremuch higher than typical global concentrations (Liu et al., 2011).So, the efficiency of the analysis method had to be tested at theappropriate level in standard and real precipitation samples.

Six organic N-containing compounds were selected: glutamicacid (C5H9NO4), porline (C5H9NO2), alanic (C3H7NO2), trytophan(C11H12O2N2), urea ((NH2)2CO), dicyandiamide (C2H4N4). A range ofconcentrations for all six standard compounds were prepared: 0, 10,

Table 2Efficiency of TDN of standard samples from prepared solutions by persulfate oxidation (

StandardSamples

0 10 25 50 75

Glumine acid 221.43 �4.36

245.74 �3.22

268.62 �2.56

276.32 �1.66

315.553.21

Proline 221.43 �4.36

243.97 �4.41

259.62 �6.28

282.35 �4.43

308.402.65

Alanine 221.43 �4.36

248.65 �9.92

260.76 �9.93

284.70 �6.63

304.564.24

Tryptophane 221.43 �4.36

230.43 �3.24

256.46 �3.24

283.70 �4.01

302.569.32

Dicyandiamide 221.43 �4.36

230.04 �3.66

248.58 �9.38

278.04 �5.84

295.304.19

Urea 221.43 �4.36

239.32 �2.87

262.57 �17.73

279.76 �6.87

303.664.41

All 221.43 �4.36

239.69 �8.62

259.43 �10.24

280.81 �5.38

305.007.64

25, 50, 75, 100 and 150 mmol L�1, 3 replicates for each concentration.2 ml sample of the same precipitation event was pipette into everyglass tube in advance, giving a typical background of the precipita-tion. Then, 2 ml of the appropriate standard sample was pipette intoeach glass tube. TDN analysis by the PO method was carried out asdescribed by Bronk et al. (2000). 10 ml standard sample for eachorganic N-containing compound at different concentrations rangewere added into each tubes. 2 ml oxidation reagent (50 g potassiumperoxydisulfate (K2S2O8), 30 g Boric acid (H3BO3), 350 ml 1 Msodium hydroxide (NaOH) andmade up to 1 L with deionizedwater)was added for each one. All the tubes were capped tightly andautoclaved at 121 �C and 15 hPa for 30 min. After the cooling of thesamples,1ml 10% hydrochloric acid (HCl) was pipette into each tube.Samples were brought up to 25 ml with deionized water and finallyanalyzed by colourimetric method.

2.4. DON determination

The frozen samples were melted at room temperature andfiltered. 2 ml samples were used for immediate NH4eN and NO3eNanalysis by Continuous Flow Analyzer (TRACCS2000, BraneLuebbeInc., Germany). It should be noted that NO3

� was converted to

unit: mmol L�1).

100 150 Correlations

y0 a r2 p

� 332.44 �1.37

377.13 �5.87

230.14 �2.55

1.02 �0.04

0.97 <0.0001

� 334.43 �5.76

383.57 �8.57

227.53 �1.91

1.06 �0.03

0.99 <0.0001

� 336.57 �5.36

384.63 �5.40

228.74 �2.41

1.06 �0.03

0.98 <0.0001

� 320.81 �3.68

362.25 �3.38

226.23 �2.19

0.95 �0.03

0.98 <0.0001

� 324.19 �7.16

366.66 �2.10

222.90 �1.68

0.98 �0.02

0.99 <0.0001

� 328.53 �7.11

374.70 �1.08

227.47 �2.45

1.00 �0.03

0.98 <0.0001

� 329.50 �7.36

374.82 �9.44

231.38 �1.33

0.97 �0.02

0.97 <0.0001

Table 3Data sources of DON concentrations in rainfall around the world from other references.

Location Duration n Ecosystem DON (mmol L-1) Reference

Marine & CoastalBBSR, Bermuda 5 Marine 5.6 Cornell et al., 1998Mace Head, Ireland 7 Marine 3.3Papeete, Tahiti 8 Marine 4.8UEA, Norwich 12 Coastal 33Newark, Delaware 1997e1999 50 Coastal 4.2 Keene et al., 2002New Castle,

New Hampshire1997 12 Coastal 0.6

Chesapeake Bay 1993e1994 60 Coastal 6.2 Russell et al., 1998La Selva, Costa Rica,

Mexico Bay1992e1993 Coastal 4.7 Eklund et al., 19971993e1994 Coastal 2.01994e1995 Coastal 10.7

North Carolina, USA 1994e1995 43 Coastal 5.5 Peierls and Paerl, 1997Rhode River,

Chesapeake Bay, USA1978 Coastal 46.8 Jordan et al., 19951979 Coastal 17.11980 Coastal 26.51981 Coastal 40.01982 Coastal 16.11983 Coastal 21.11984 Coastal 21.21985 Coastal 16.71986 Coastal 16.91987 Coastal 23.01988 Coastal 23.21989 Coastal 15.51990 Coastal 12.61991 Coastal 26.5

Atlantic Ocean Marine 0.0065 Lesworth et al., 2010Oahu, Hawaii Marine 2.8 Cornell et al., 2002Lewes, Delaware, USA 1993e1994 37 Coastal 9 Scudlard et al., 1998Finokalia, Easter

Mediterranean Basin2003e2006 74 Remote marine 23 Violaki et al., 2010

Gulf of Aqaba, Jordan Coastal 11.3 Wedyan and Fandi, 2007Long Island Sound, USA 1991e1994 Coastal 17.9 Luo et al., 2002

1997e1999 Coastal 7.9Coastal 12.9

Bermuda 16 Cornell et al., 1995Tahiti 13NE Atlantic 8NE Atlantic 6

ForestHubbard Brook 6, USA 1995e1996 Forest 6.3 Campbell et al., 2000

1996e1997 Forest 9.8Hubbard Brook 7, USA 1995e1996 Forest 6.2



1996e1997 Forest 10.0Cone Pond, USA 1995e1996 Forest 6.5

1996e1997 Forest 6.8Sllpers River, USA 1995e1996 Forest 9.3

1996e1997 Forest 8.7Lye Brook Wilderness, USA 1994e1995 Forest 8.9Thailand 1998e2001 Forest 14.3 Möller et al., 2005Ravels, Belgium Forest 25.0 Vandenbruwane et al., 2007

Forest (throughfall) 40.7Finland 1993e1996 Forest 22.9 Piirainen et al., 1998

Forest (throughfall) 25.0Climoor, north Wales 2000e2002 25 Grass clearing

in forest29 Cape et al., 2004

Tampa Bay, Florida 2005 Forest characterizedby intensive livestockbreeding

4.7 Calderón et al., 2007

GrasslandMerlewood, northwest

England2000e2002 68 Grass field,

country estate35 Cape et al., 2004

Moor House, northwestEngland

2000e2002 55 Open moorland,remote

31

Wifrith, southwestEngland

2000e2002 61 Grassland,research park

23

Cairngorm, northeastScotland

2000e2002 30 Open hillside, moorland 14


Table 3 (continued )

Location Duration n Ecosystem DON (mmol L-1) Reference

AgricultureEdinburgh 2005e2007 38 Mixed farming

(arable þ dairy)14 González Benítez

et al., 2009Edinburgh 2005e2007 35 Mixed farming

(arable þ dairy)5.4

Japan 1999e2003 Intensiveagricultural area

Ham and Tamiya, 2006

Bush, eastScotland

2000e2002 54 Non-intensiveagriculture

15 Pacheco et al., 2004

RuralCzech Republic Rural 7 Cornell et al., 1995nothern Carolina Rural 9Maraba, Amazonia Rural 22Recife, Brazil Rural 3Barranquitas,

Venezuela1991e1994 8 Rural, lakeshore 69.3 Morales et al., 2001

Sta Barbara,Venezuela

1991e1994 34 Rural, lakeshore 57.1

La Ceiba,Venezuela


Canal VOC,Venezuela


Calabozo,Venezuela

17 rural 24 Pacheco et al., 2004

UrbanUEA, UK Urban/rural 18 Cornell et al., 1995Maracaibo,

Venezuela1991e1994 60 Urban 34.3 Morales et al., 2001

Valencia,Venezuela

30 Urban 57 Pacheco et al., 2004

Caracas,Venezuela

9 Urban 58

Altos de Pipe,Venezuela

14 Suburban 31

Norwich University,Southeast England

2001e2002 25 Suburban parkbeside lake

33

*Blanks in columns of “duration” and “n” mean lack of information.


NO2� during the chemical analysis. So, NO2eN here was included in

the analysis, and NO3eN equals the sum of NO2eN and NO3eN.Another 5 ml samples were pipetted for TDN analysis. The

sample volume was modified to 5 ml instead of 15 ml as in the POmethod of Bronk et al. (2000) because of the higher TDN concen-trations in our research. The oxidation reagent and oxidizingconditions were the same as for the standard samples. DONconcentration was defined as the difference between TDN anddissolved inorganic nitrogen, i.e.

DON ¼ TDN� DIN ¼ TDN� ðNH4 � Nþ NO3 �NÞTDNwas analyzed by colourimetric method after the conversion

of all the N compounds to NO3� via the PO method as above.

3. Results and discussion

3.1. Persulfate oxidation efficiency

The efficiency of the persulfate oxidation is shown in Table 2.All the correlations of the six standard organic N-containingcompoundswere very significant (p< 0.0001). Recoveries of the sixstandard samples ranged from 95 to 106%, with an average value of97%. The highest recoveries were found for proline and alanine andthe lowest for tryptoph, which may be partly due to the uncer-tainties during the determination of TDN and DIN. Despite thisrange, the method is appropriate for our analysis. Compared toother oxidation methods (i.e., Cornell et al., 2003), the PO methodshowed relatively good oxidation efficiency for the range of organicN-containing compounds we studied.

3.2. Spatial variations

Volume-weighted concentrations of DON ranged from 13 to190 mmol L�1, with an average value of 77 mmol L�1 (Fig. 2a). Thelowest DON concentration was found at FZ, a site located ina coastal area with high annual precipitation, which diluted theDON content; the highest DON concentrationwas found at FS, a sitelocated in an agricultural area downwind of Beijing, which wasinfluenced by both agricultural and urban pollution sources. In theNCP (sites 1e13), the DON concentration was 101 mmol L�1 onaverage. Taking the annual average precipitation of this region of500 mm into account, it meant that about 7 kg N ha�1 yr�1 DON isdeposited in addition to DIN deposition, which was about30 kg N ha�1 yr�1 (Liu et al., 2006; Zhang et al., 2008b). DONconcentration at site 3, in the urban area, was lower than that atother sites. We would therefore expect more agricultural source ofDON in the NCP. DON concentrations in arid regions were compa-rable to those in the NCP, but DON deposition rates were muchlower due to there being less precipitation (Fig. 2b). DON concen-trations were higher at sites 14 to 16 than at site 17 because sites 14to 16 are located in steppe areas, which are likely to be influencedby livestock. Site 17 is located in a non-intensified agricultural areawithout livestock. Annual DON deposition was less than2.8 kg N ha�1 yr�1 based on the annual precipitation of�200mmofthis region. DON concentrations at sites 18 to 20 in the SC areawereonly half those at sites 21 to 23 in the KM area. Both sites are locatedin agricultural areas in the southwest of China and both receiveannual precipitation of about 1100 mm, but sites in the SC area arelocated in farmland and surrounded by mountains covered bynatural forests, while KM is in an intensive vegetable production

0

40

80

120

160

200

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

NCP Arid SC KM Coastal FJ Forest

Con

cent

ratio

n (u

mol

L-1

)

0

4

8

12

16

20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32


Dep

ositi

on (

kg N

ha-1

yr-1

)

0

10

20

30

40

50

60

70

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32


Con

trib

utio

n (%

)

c

a

b

Fig. 2. Concentrations, deposition and contributions of DON at themonitoring sites (a. volume-weighted concentrations (mmol L�1); b. deposition (kg N ha�1 yr�1); c. contributions (%)).


area receiving large amounts of organic fertilizers. Therefore DONdeposition at KM was 12.4 kg N ha�1 yr�1 (the highest DONdeposition reached 19.7 kg N ha�1 yr�1), which was even higherthan that in the NCP, the typical intensive agricultural area. Sites24 to 27 are located in the coastal region, ranging from the north tothe south. DON concentrations at these four sites decreased withlatitude, partly because precipitation increased in the same direc-tion. However, there was more pollution from both agriculture andindustry influencing sites 24 to 26. DON deposition at sites 24, 25and 26 was 10 kg N ha�1 yr�1 on average, while it was<4 kg N ha�1 yr�1 at site 27. The average DON concentration in theFJ region (sites 28e30) was <35 mmol L�1, but the average depo-sition was as high as 7.3 kg N ha�1 yr�1. DON concentration at site31 was only half of that at site 32, but the deposition was compa-rable with these sites because of much higher annual precipitation.Site 32 was located in a remote area with less pollution, but theDON concentration was 43 mmol L�1, about three times the lowest

value in this study. This was because, firstly, the annual precipita-tion was only 650 mm, much less than that in the southern or thecoastal regions; secondly, DON comprised 67% of the TDN at site 32(Fig. 2c). Both concentration and deposition of DIN at site 32 werecomparable with results observed in remote areas in other places inthe world (Zhang et al., 2008a).

The average contribution of DON to TDN was 28%, but rangedfrom 7% to 67% (Fig. 2c). The largest contributions of DON werefound at site 32, the remote forest site. This contrasts with the verysmall contributions of DIN concentration in this area. Our resultssupport previous research that DON is the main component ofN biogeochemical cycling in remote forest regions (Van Breemen,2002). Another region with a large DON component, about 50% ofthe TDN, was KM, which was greatly affected by the organicmanures used in agriculture. The lowest DON contribution wasfound at site 3, the site located in the urban area. NO3eN concen-tration and depositionwere high because of traffic pollution (Zhang

Reference This study

Marine & Coastal Forest Grassland Agricultural Rural Urban

DO

N C

once

ntra

tion

(um

ol L

-1)

0

50

100

150

200

250

Coastal* Forest* Grassland* Agricultural* Urban*

(n=20)

(n=4)(n=6)

(n=2)

(n=2)

(n=1)(n=37)(n=4)

(n=9)(n=4)

(n=23)

b

Reference

DO

N C

once

ntra

tion

(um

ol L

-1)

0

50

100

150

200

250

This study

(n=32)

(n=80)

a

Fig. 3. Distribution of DON concentrations in China from this research and at other sites around the world from the literature (a. whole group comparison; b. subgroup comparison.Gray boxes with * mean data from reference; white boxes mean data from this study). (All the data sources of references were listed in Table 3).


et al., 2008a,b), and this could result in the presence of PAN(Peroxyacetyl Nitrate) and alkyl nitrates in the DON. But DON wasnot the main component of TDN deposition, because PAN and alkylnitrates are less soluble (Cornell et al., 2003).

DON concentrations in precipitation in this study and otherparts of theworld are shown in Fig. 3. The DON concentrations fromthis study were about four times those elsewhere (Fig. 3a).Considering the difference between ecosystems, all the data weredivided into subgroups according to the characteristics of thelocation (Fig. 3b). DON concentrations in coastal regions in thisstudy were higher than those in other countries because mostreferenced data in this subgroup relates to remote marine andcoastal regions, while the coastal region in China receives pollutiondue to economic development. Chen et al. (2011) measured depo-sition at three sites in the southeast China coastal area and foundthat the average DON concentration was 71 mmol L�1, consistentwith our results. DON concentrations at our forest sites were alsohigher than referenced values. Fang et al. (2008) found even higherDON concentrations at a forest site in Guangdong, southeast China,with a value of 76 mmol L�1, which could be explained by the largerpollution load in that region, resulting in both higher concentra-tions of NH4eN and NO3eN at the same time. Grasslands in ourstudy were located in arid regions with less precipitation, so theconcentrations of DON that we measured were much higher thanthose referenced. DON concentrations in our agricultural areaswere higher than those referenced because of the influence ofintensive agricultural activities in our study. Wang et al. (2004) andYang et al. (2010) found DON concentrations ranged from 29 to64 mmol L�1 in precipitation in agricultural areas in Jiangsu prov-ince, east China. Concentrations measured were lower than thosefor sites in the NCP but consistent with results for sites in otheragricultural regions in our study, which could be explained mainlyby the influence of precipitation. The measured DON concentrationat the urban site was comparable with the referenced data, whichwere all affected by traffic. All our results indicate previouslyignored significant bulk deposition of DON in China.

3.3. Seasonal variations

Sites with similar climatic conditions were grouped together.Comparisons of seasonal variations of DON concentrations anddeposition with wind frequency roses were carried out (Fig. 4).Seasonal variations of wind frequency at weather stations at ornearby the monitoring sites are shown in Fig. 4c, and consist ofmore than ten years (1997e2008) radiosonde data from the British

Atmospheric Data Centre (BADC) (2008). Except for FZ, the DONconcentrations and deposition varies with seasons (Fig. 4a), largelydriven by seasonal variations in rainfall (Fig. 4b). Thus lowerconcentrations but higher deposition rates were mostly found insummer and autumn.

Both higher DON deposition and contribution to TDN werefound in spring and summer in the NCP (Fig. 4a,b), which can beexplained by anthropogenic activity as well as climatic conditions.As an intensive agricultural region, fertilizer N was mainly appliedin the spring and summer, of which 67% was in the form of urea(IFA, 2009). Although not all the organic nitrogenous species weredetected, urea was expected to be higher with possibility of directinjection into the atmosphere (Neff et al., 2002; Cornell, 2011).Bai (2009) analyzed urea in the precipitation in the NCP, and foundit contributed 43% of the DON in this region, which furtherconvinced the influence of agricultural sources. Conversely, lowerDON deposition was found in winter. Less agricultural activitieswere conducted during this period, while more fuel combustion forheating happened, which could produced more oxidized inorganicnitrate as well as oxidized organic nitrates for the photochemicalreactions. But the contribution of the increased oxidized organicnitrates could not compete with the decreased reduced organicnitrogen for the lower contribution of DON to TDN. In addition,aerosols of DON occurring from spring to autumn originatedmostlyfrom the southwest of the NCP where there was more anthropo-genic activity, while aerosols of DON from the northwest of theNCP, Western Siberia, Mongolia and Inner Mongolia, made largercontributions in winter (Fig. 4c). No significant variations withseason in DON concentration, deposition and contribution to TDNwere found in the arid area because of the very small anthropo-genic influence, relatively constant low precipitation and lack ofany seasonal basis in wind frequency (Fig. 4).

Similar seasonal variations in DON concentration, depositionand contribution to TDN were found at DA, QD and FH - sites in thecoastal region (Fig. 4a,b), but sources of the aerosols were differentas deduced from the wind frequency rose (Fig. 4c). More aerosolswere transported from the south rather than the north at DA andQD, illustrating the greater contribution from oceanic sourcesrather than inland sources. The wind frequency rose at FH showedthat both inland and oceanic sources influenced DON depositionthere in summer while oceanic sources were dominant in otherseasons (Fig. 4c). Seasonal variations in DON concentration anddeposition at FZ were driven by rainfall as well as wind direction;we cannot explain the contribution of DON to TDN on the basis ofrainfall and wind direction or speed. We need further information

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5 0

50

100

150

200

250

Spr

ing

Sum

mer

Aut

umn

Win

ter

Spr

ing

Sum

mer

Aut

umn

Win

ter

Spr

ing

Sum

mer

Aut

umn

Win

ter

Spr

ing

Sum

mer

Aut

umn

Win

ter

Spr

ing

Sum

mer

Aut

umn

Win

ter

Spr

ing

Sum

mer

Aut

umn

Win

ter

Spr

ing

Sum

mer

Aut

umn

Win

ter

NCP Arid DA QD FH FZ SC

Dep

ositi

on (

kgnN

ha-1

mon

th- 1

)

Con

cent

ratio

n (µ

mol

L-1

)Concentration

Deposition

0

100

200

300

400

0

10

20

30

40

Spr

ing

Sum

mer

Aut

umn

Win

ter

Spr

ing

Sum

mer

Aut

umn

Win

ter

Spr

ing

Sum

mer

Aut

umn

Win

ter

Spr

ing

Sum

mer

Aut

umn

Win

ter

Spr

ing

Sum

mer

Aut

umn

Win

ter

Spr

ing

Sum

mer

Aut

umn

Win

ter

Spr

ing

Sum

mer

Aut

umn

Win

ter


Rai

nfal

l (m

m)

DO

N/T

DN

(%

)

DON/TDN Rainfall

c

Spri

ngS

umm

erA

utum

nW

inte

r


a

b

Fig. 4. Seasonal variations in DON concentrations, DON deposition, the ratio of DON to TDN, rainfall and wind frequency roses at some of the monitoring sites. (a. concentrationsand deposition of DON; b. contributions of DON to TDN and rainfall; c. wind frequency roses. Sites with similar climatic conditions were grouped. NCP (sites 1e13); Arid (sites14e16); DA (site 24); QD (site 25); FH (site 26); FZ (site 27); SC (sites 18e20). Sites in coastal regions were separated according to their large variation of latitude. Sites in the KMregion were excluded because we had only one season’s (spring) data and so little change; site 32 in the remote forest regions were excluded because of the lack of weather data(radiosonde data) because of the very high altitude. Spring ¼ March, April and May; summer ¼ June, July and August; autumn ¼ September, October and November;winter ¼ December, January and February. Data used for the wind frequency roses were 6-hourly operational radiosonde data spanning a ten-year period (1997e2008), obtainedfrom the British Atmospheric Data Centre, 2008).


other than that available from only one year’s data (Table 1).Seasonal variations in DON concentration, deposition and contri-bution to TDN in the SC regionwere the same as those at sites in theNCP, with aerosol sources originating mainly from the northeast(Fig. 4).

3.4. Relationships between DON, NH4eN, NO3eN and TDN

Correlations between DON and rainfall, DON and NH4eN, DONand NO3eN, and DON and TDN are shown in Fig. 5 using annualaverages from this study and the literature. Statistically significant,

NH4-N (umol L-1)

0 100 200 300 400 500

DO

N C

once

ntra

tion

(um

ol L

-1)

0

50

100

150

200

250

NO3-N (umol L-1)

0 100 200 300 400

DO

N C

once

ntra

tion

(um

ol L

-1)

0

50

100

150

200

250

TDN (umol L-1)

0 200 400 600 800

DO

N C

once

ntra

tion

(um

ol L

-1)

0

50

100

150

200

250

a b

c

y=0.29x+13.45

(r2=0.33; n=6; p<0.0001)

y1=0.21x1+48.91

(r2=0.1 n=81; p<0.0001)

y=0.45x+9.88

(r2=0.21; n=0.21; p=0.0001)

y1=0.17x1+65.34

(r2=0.05; n=81; p=0.04)

y=0.24x+4.57

(r2=0.63; n=69; p<0.0001)

y1=0.17x1+21.08

(r2=0.38; n=81; p<0.0001)

Fig. 5. Correlations of DON with NH4eN, NO3eN, TDN (a. annual DON concentration vs. annual NH4eN concentration; b. annual DON concentration vs. annual NO3eN concen-tration; c. annual DON concentration vs. annual TDN concentration)(open dots represent results from this study; solid dots represent results from references; solid lines representcorrelations (y, x) conducted from reference data; dash lines represent correlations (y1, x1) conducted from this study; reference data sources include those in Table 3 and otherresults for China, i.e. Chen et al., 2011; Fang et al., 2008; Wang et al., 2004; Yang et al., 2010).


positive linear regressions between DON and NH4eN, DON andNO3eN, DON and TDN were observed, but correlations for thisstudy were not as robust as those for literature data (Fig. 5).Moreover, most concentration values from literature results wereconcentrated in lower concentration zone, while most concentra-tion values from this study were concentrated in higher concen-tration zone. This suggests that similar origins of atmosphericorganic and inorganic N compounds in bulk deposition in otherplaces in the world, and natural background sources take moreparts in the origins. However, at monitoring sites with high Ndeposition rates in China, origins of DON deposition are morecomplicated. Firstly, DON deposited in China derives mostly fromanthropogenic sources rather than natural background sources forthe higher concentrations; secondly, the r2 value for DON vs.NH4eNwas higher than that of DON vs. NO3eN, suggesting that theorigin of DONwasmore closely related to NH4eN than it to NO3eN;i.e. to reduced rather than oxidized organic N compounds; thirdly,the agricultural sources, oceanic sources as well as meteorologicalfactors work together on the DON deposition in China, and furtherstudies should focus on the specific organic N species in wet anddry deposition (Liu et al., 2011); last, both the data from China andother places in the world showed that DON concentrations signif-icantly increased with TDN concentrations (Fig. 5c), and DON isa significant contributor to N deposition at the global scale.

4. Conclusion

DON deposition at 32monitoring sites in China ranged from1.01to 19.7 kg N ha�1 yr�1, with an average value of 6.84 kg N ha�1 yr�1,accounting for 28% of TDN. Higher volumeweighted concentrationswere found at sites with less precipitation, while lower volumeweighted concentrations were found at sites with more precipita-tion. Higher contributions of DON to TDN were found in remoteforest regions and in agricultural regions where organic fertilizerwas applied. Seasonal variations of DON concentration and depo-sitionweremostly driven by rainfall andwind direction. Combiningdeposition and rainfall data with wind frequency suggested thatagriculture and oceanic spray were the main sources of DON. Ourresults reveal that DON is a significant source of deposited N andmust be measured and analyzed for composition if we are to geta true picture of N deposition and its sources and impacts.

Acknowledgement

This work was supported by the Hundred Talent Program of theChinese Academy of Sciences, the National Natural Science Founda-tion of China (NSFC) (41071151, 40771188), the Innovative GroupGrants from NSFC (30821003) and the Chinese National Basic


Research Program (2009CB118606).We acknowledge Profs. Dr. KeithGoulding andNeil Cape for their comments and linguistic corrections.

References

Bai, Z.C., 2009. Characteristics of atmospheric organic nitrogen deposition indifferent ecological regions in China. M.S. thesis, China Agricultural University,Beijing.

Bobbink, R., Galloway, H.J., Spranger, T., Alkemade, R., Ashmore, M., Bustamante, M.,Cinderby, S., Davidson, E., Dentener, F., Emmett, B., Erisman, J.W., Fenn, M.,Gillian, F., Nordin, A., Pardo, L., De Vries, W., 2010. Global assessment of nitrogendeposition effects on terrestrial plant diversity: a synthesis. Ecological Appli-cations 20, 30e59.

British Atmospheric Data Centre, 2008. http://badc.nerc.ac.uk/home/index.html.Bronk, D.A., Lomas, M.W., Glibert, P.M., Schukert, K.J., Sanderson, M.P., 2000. Total

dissolved nitrogen analysis: comparisons between the persulfate, UV and hightemperature oxidation methods. Marine Chemistry 69, 163e178.

Bronk, D.A., See, J.H., Bradley, P., Killberg, L., 2007. DON as a source of bioavailablenitrogen for phytoplankton. Biogeosciences 4, 283e296.

Calderón, S.M., Poor, N.D., Campbell, S.W., 2007. Estimation of the particle and gasscavenging contributions to wet deposition of organic nitrogen. AtmosphericEnvironment 41, 4281e4290.

Campbell, J.L., Hornbeck, J.W., McDowell, W.H., Buso, D.C., Shanley, J.B., Likens, G.E.,2000. Dissolved organic nitrogen budgets for upland, forested ecosystems inNew England. Biogeochemistry 49, 123e142.

Cape, J.N., Anderson, M., Rowland, A.P., Wilson, D., 2004. Organic nitrogen in precipi-tation across the United Kingdom. Water, Air, & Soil Pollution: Focus 4, 25e35.

Cape, J.N., Kirika, A., Rowland, A.P., Wilson, D.R., Jickells, T.D., Cornell, S., 2001.Organic nitrogen in precipitation: real problem or sampling artifact? TheScientific World S2, 230e237.

Chen, N., Hong, H., Huang, Q., Wu, J., 2011. Atmospheric nitrogen deposition and itslong-term dynamics in a southeast China coastal area. Journal of EnvironmentalManagement 92, 1663e1667.

Cornell, S.E., 2011. Atmospheric nitrogen deposition: revisiting the question of theimportance of the organic component. Environmental Pollution 159, 2214e2222.

Cornell, S., Rendell, A., Jickells, T., 1995. Atmospheric inputs of dissolved organic tothe ocean. Nature 376, 243e246.

Cornell, S., Mace, K., Coeppicus, S., Duce, R., Hueber, B., Jickells, T., Zhuang, L.Z., 2002.Organic nitrogen in Hawaii rain and aerosol. Journal of Geophysical Research106 (D8), 7973e7983. doi:10.1029/2000JD900655.

Cornell, S.E., Jickells, T.D., Thornton, C.A., 1998. Urea in rainwater and atmosphericaerosol. Atmospheric Environment 32, 1903e1910.

Cornell, S.E., Jickells, T.D., 1999. Water-soluble organic nitrogen in atmosphericaerosol: a comparison of UV and persulfate oxidation methods. AtmosphericEnvironment 33, 833e840.

Cornell, S.E., Jickells, T.D., Cape, J.N., Rowland, A.P., Duce, R.A., 2003. Organicnitrogen deposition on land and coastal environments: a review of methodsand data. Atmospheric Environment 37, 2173e2191.

Doyle, A., Weintraub, M.N., Schimel, J.P., 2004. Persulfate digestion and simulta-neous colorimetric analysis of carbon and nitrogen in soil extracts. Soil ScienceSociety of America Journal 68, 669e676.

Duce, R.A., LaRoche, J., Altieri, K., Arrigo, K.R., Baker, A.R., Capone, D.G., Cornell, S.,Dentener, F., Galloway, J., Ganeshram, R.S., Geider, R.J., Jickells, T., Kuypers, M.M.,Langlois, R., Liss, P.S., Liu, S.M., Middelburg, J.J., Moore, C.M., Nickovic, S.,Oschlies, A., Pedersen, T., Prospero, J., Schlitzer, R., Seitzinger, S., Sorensen, L.L.,Uematsu, M., Ulloa, O., Voss, M., Ward, B., Zamora, L., 2008. Impacts of atmo-spheric anthropogenic nitrogen on the open ocean. Science 320, 893e897.

Eklund, T.J., McDowell, W.H., Pringle, C.M., 1997. Seasonal variation of tropical precip-itation chemistry: La Selva, Costa Rica. Atmospheric Environment 31, 3903e3910.

Fang, Y.T., Gundersen, P., Mo, J.M., Zhu, W.X., 2008. Input and output of dissolvedorganic and inorganic nitrogen in subtropical forests of South China under highair pollution. Biogeosciences 5, 339e352.

Galloway, J.N., Dentener, F.J., Capone, D.G., Boyer, E.W., Howarth, R.W.,Seitzinger, S.P., Asner, G.P., Cleveland, C.C., Green, P.A., Holland, E.A., Karl, D.M.,Michaels, A.F., Porter, A.H., Townsend, A.R., Vöosmarty, C.J., 2004. Nitrogencycles: past, present, and future. Biogeochemistry 70, 153e226.

Guo, J.H., Liu, X.J., Zhang, Y., Shen, J.L., Han, W.X., Zhang, W.F., Christie, P.,Goulding, K.W.T., Vitousek, P.M., Zhang, F.S., 2010. Significant acidification inmajor Chinese croplands. Science 327, 1008e1010.

González Benítez, J.M., Cape, J.N., Heal, M.R., van Dijk, N., Díez, A.V., 2009. Atmo-spheric nitrogen deposition in south-east Scotland: quantification of theorganic nitrogen fraction in wet, dry and bulk deposition. Atmospheric Envi-ronment 43, 4087e4094.

Ham, Y., Tamiya, S., 2006. Contribution of dissolved organic nitrogen deposition tototal dissolved nitrogen deposition under intensive agricultural activities.Water, Air, & Soil Pollution 178, 5e13.

IFA, 2009, http://www.fertilizer.org/ifa/ifadata/search.Jordan, T.E., Correll, D.L., Weller, D.E., Goff, N.M., 1995. Temporal Variation in

precipitation chemistry on the shore of the Chesapeake Bay. Water, Air, & SoilPollution 83, 263e284.

Keene, W.C., Montag, J.A., Maben, J.R., Southwell, M., Leonard, J., Church, T.M.,Moody, J.L., Galloway, J.N., 2002. Organic nitrogen in precipitation over Easternnorth America. Atmospheric Environment 36, 4529e4540.

Lesworth, T., Baker, A.R., Jickells, T., 2010. Aerosol organic nitrogen over the remoteAtlantic Ocean. Atmospheric Environment 44, 1887e1893.

Liu, X., Ju, X., Zhang, Y., He, C., Kopsch, J., Zhang, F., 2006. Nitrogen deposition inagroecosystems in the Beijing area. Agriculture Ecosystems & Environment 113,370e377.

Liu, X.J., Duan, L., Mo, J.M., Du, E.Z., Shen, J.L., Lu, X.K., Zhang, Y., Zhou, X.B., He, C.E.,Zhang, F.S., 2011. Nitrogen deposition and its ecological impact in China: anoverview. Environmental Pollution 159, 2251e2264.

Luo, Y., Yang, S., Carley, R.J., Perkins, C., 2002. Atmospheric deposition of nitrogenalong the Connecticut coastline of Long Island Sound: a decade of measure-ments. Atmospheric Environment 36, 4517e4528.

Möller, A., Kaiser, K., Guggenberger, G., 2005. Dissolved organic carbon and nitrogenin precipitation, throughfall, soil solution, and stream water of the tropicalhighlands in northern Thailand. Journal of Plant Nutrition and Soil Science 168,649e659.

Morales, J.A., Sanchez, L., Velasquez, H., de Borrego, B., de Nava, M., Portillo, D.,Cano, Y., Morillo, A., Albornoz, A., Socorro, E., 2001. Nutrient loading byprecipitation in the Maracaibo lake basin, Venezuela. Water, Air, & Soil Pollution130, 511e516.

Näsholm, T., Ekblad, A., Nordin, A., Giesler, R., Högberg, M., Högberg, P., 1998. Borealforest plants take up organic nitrogen. Nature 392, 914e916.

Neff, J.C., Holland, E.A., Dentener, F.J., McDowell, W.H., Russell, K.M., 2002. Theorigin, composition and rates of organic nitrogen deposition: a missing piece ofthe nitrogen cycles? Biogeochemistry 57/58, 99e136.

Pacheco, M., Donoso, L., Sanhueza, E., 2004. Soluble organic nitrogen in Venezuelanrains. Tellus 56B, 393e395.

Peierls, B.L., Paerl, H.W., 1997. Bioavailability of atmospheric organic nitrogen depo-sition to coastal phytoplankton. Limnology and Oceanography 42, 1819e1823.

Piirainen, S., Finér, L., Starr, M., 1998. Canopy and soil retention of nitrogen depo-sition in a mixed boreal forest in Eastern Finland. Water, Air, & Soil Pollution105, 165e174.

Rogora, M., Minella, M., Orrù, A., Tartari, G.A., 2006. A comparison between high-temperature catalytic oxidation and persulphate oxidation for the determina-tion of total nitrogen in freshwater. International Journal of Environmental andAnalytical Chemistry 86, 1065e1078.

Russell, K.M., Galloway, J.N., Macko, S.A., Moody, J.L., Scudlark, J.R., 1998. Sources ofnitrogen in wet deposition to the Chesapeake Bay region. Atmospheric Envi-ronment 32, 2453e2465.

Scudlard, J.R., Russell, K.M., Galloway, J.N., Church, T.M., Keene, W.C., 1998. Organicnitrogen in precipitation at the Mid-Atlantic U.S. coast-methods evaluation andpreliminary measurements. Atmospheric Environment 32, 1719e1728.

Sharp, J.H., Beauregard, A.Y., Burdige, D., Cauwet, G., Curless, S.E., Lauck, R., Nagel, K.,Ogawa, H., Parker, A.E., Primm, O., Pujo-Pay, M., Savidge, W.B., Seitzinger, S.,Spyres, G., Styles, R., 2004. A direct instrument comparison for measurement oftotal dissolved nitrogen in seawater. Marine Chemistry 84, 181e193.

Van Breemen, N., 2002. Natural organic tendency. Nature 415, 381e382.Vandenbruwane, J., De Neve, S., Qualls, R.G., Salomez, J., Hofman, G., 2007. Opti-

mization of dissolved organic nitrogen (DON) measurements in aqueoussamples with high inorganic nitrogen concentrations. Science of the TotalEnvironment 386, 103e113.

Violaki, K., Zarbas, P., Mihalopoulos, N., 2010. Long-term measurements of dissolvedorganic nitrogen (DON) in atmospheric deposition in the Eastern Mediterra-nean: fluxes, origin and biogeochemical implications. Marine Chemistry 120,179e186.

Wang, X.Z., Zhu, J.G., Gao, R., Hosen, Y., 2004. Dynamics and ecological significanceof nitrogen wet deposition in Taihu Lake region-Taking Changshu Agro-ecological Experiment station as an Example. Chinese Journal of AppliedEcology 15, 1616e1620.

Wedyan, M.A., Fandi, K., 2007. Soluble organic nitrogen in the marine aerosolover the Gulf of Aqaba (Jordan). Journal of Applied Sciences Research 3,787e790.

Yang, R., Hayashi, K., Zhu, B., Li, F., Yan, X., 2010. Atmospheric NH3 and NO2concentration and nitrogen deposition in an agricultural catchment of EasternChina. Science of the Total Environment 408, 4624e4632.

Zhang, Y., Zheng, L.X., Liu, X.J., Jickells, T., Cape, J.N., Goulding, K., Fangmeier, A.,Zhang, F.S., 2008a. Evidence for organic N deposition and its anthropogenicsources in China. Atmospheric Environment 42, 1035e1041.

Zhang, Y., Liu, X.J., Fangmeier, A., Goulding, K.T.W., Zhang, F.S., 2008b. Nitrogeninputs and isotopes in precipitation in the North China Plain. AtmosphericEnvironment 42, 1426e1448.

http://badc.nerc.ac.uk/home/index.html

http://www.fertilizer.org/ifa/ifadata/search

atmospheric organic nitrogen deposition in china

Documents