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Bibliometrics
Bibliometric Analysis for the U.S. Environmental Protection Agency/Office of Research and Development’s Air (Particulate Matter, Ozone, Air Toxics, and Indoor Air) Research Program
September 21, 2007This is a bibliometric analysis of the papers prepared by intramural and extramural researchers of the U.S. Environmental Protection Agency’s (EPA) Air Research Program. For this analysis, 2,064 papers were reviewed, and they were published from 1998 to 2007. These publications were cited 34,562 times in the journals covered by Thomson Scientific’s Web of Science1 and Elsevier’s Scopus2. Of these 2,064 publications, 1,827 (88.5%) have been cited at least once in a journal.
Searches of Web of Science and Scopus were conducted to obtain times cited data for the Air Research Program journal publications. The analysis was completed using Thomson’s Essential Science Indicators (ESI) and Journal Citation Reports (JCR) as benchmarks. ESI provides access to a unique and comprehensive compilation of essential science performance statistics and science trends data derived from Thomson’s databases. For this analysis, the ESI highly cited papers thresholds as well as the hot papers thresholds were used to assess the influence and impact of the air papers. JCR is a recognized authority for evaluating journals. It presents quantifiable statistical data that provide a systematic, objective way to evaluate the world’s leading journals and their impact and influence in the global research community. The two key measures used in this analysis to assess the journals in which the EPA air papers are published are the Impact Factor and Immediacy Index. The Impact Factor is a measure of the frequency with which the “average article” in a journal has been cited in a particular year. The Impact Factor helps evaluate a journal’s relative importance, especially when compared to other journals in the same field. The Immediacy Index is a measure of how quickly the “average article” in a journal is cited. This index indicates how often articles published in a journal are cited within the same year and it is useful in comparing how quickly journals are cited.
The report includes a summary of the results of the bibliometric analysis, an analysis of the 2,064 air research papers analyzed by ESI field (e.g., Clinical Medicine, Environment/Ecology, and Geosciences), an analysis of the journals in which the air papers were published, a table of the highly cited researchers in the Air Research Program, a list of patents that have resulted from the program, and other parameters reported by ESI.
Summary of Results
- One-third of the air publications are highly cited papers. 679 (32.9%) of the air papers qualify as highly cited when using the ESI criteria for the top 10% of highly cited publications. This is 3.3 times the 10% of papers expected to be highly cited. 107 (5.2%) of the air papers qualify as highly cited when using the ESI criteria for the top 1%, which is 5.2 times the number expected. 14 (0.7%) of these papers qualify as very highly cited when using the criteria for the top 0.1%, which is 7 times the number anticipated. None of the papers actually meets the 0.01% threshold for the most highly cited papers, which is not surprising given that the expected number for this program is 0.2 papers.
- The air papers are more highly cited than the average paper. Using the ESI average citation rates for papers published by field as the benchmark, in 15 of the 19 fields in which the 2,064 EPA air papers were published, the ratio of actual to expected cites is greater than 1, indicating that the air papers are more highly cited than the average papers in those fields. For all 19 fields combined, the ratio of total number of cites to the total number of expected cites (34,562 to 15,305.25) is 2.2, indicating that the air papers are more highly cited than the average paper.
- More than one-third of the air papers are published in high impact journals. 696 of the 2,064 papers were published in the top 10% of journals ranked by JCR Impact Factor, representing 33.7% of EPA’s air papers. This number is 3.4 times higher than the expected 206 papers. 966 of the 2,064 papers appear in the top 10% of journals ranked by JCR Immediacy Index, representing 46.8% of EPA’s air papers. This number is 4.7 times higher than the expected 206 papers.
- Fifty-two of the air papers qualify as hot papers. Using the hot paper thresholds established by ESI as a benchmark, 52 hot papers, representing 2.5% of the air papers, were identified in the analysis. Hot papers are papers that were highly cited shortly after they were published. The number of air hot papers identified is 25 times higher than the expected 2 hot papers.
- The authors of the air papers cite themselves much less than the average author. 1,605 of the 34,562 cites are author self-cites. This 4.6% author self-citation rate is well below the accepted range of 10-30% author self-citation rate.
- Fifty-nine of the 3,452 authors of the air papers are included in ISIHighlyCited.com,which is a database of the world’s most influential researchers who have made key contributions to science and technology during the period from 1981 to 1999.
- There were 6 patents issued to investigators from 1998 to 2007 for research that was conducted under EPA’s Air Research Program. Two of these patents were cited by a total of 9 other patents.
- EPA’s Air Research Program includes 4 of the top 20 air pollution papers (published from January 2003 to April 2005) and 18 of the top 20 air pollution authors (from 1995 to 2005) authored papers for EPA’s Air Research Program.
- The United States ranks first among the top 20 countries publishing on air pollution.
- More than one-half of the EPA air papers are published in ESI’s top 20 journals in air pollution.
- Harvard University (one of EPA’s grantees) ranks number one and EPA ranks number two on ESI’s top 20 institutions publishing on air pollution.
- The number of air pollution papers published in journals covered by ESI from 2001 to 2005 has declined compared to the number published from 2000 to 2004. The number of cites and cites/paper for papers published from 2001 to 2005 also have declined. The number of EPA Air Research Program publications, however, has increased slightly from 2001 to 2005 (1,257 publications) when compared to the number published from 2000 to 2004 (1,240 publications). Like the overall air pollution paper trends identified by ESI, the number of cites and the cites per paper have declined.
Highly Cited Air Publications
All of the journals covered by ESI are assigned a field, and to compensate for varying citation rates across scientific fields, different thresholds are applied to each field. Thresholds are set to select highly cited papers to be listed in ESI. Different thresholds are set for both field and year of publication. Setting different thresholds for each year allows comparable representation for older and younger papers for each field.
The 2,064 air research papers reviewed for this analysis were published in journals that were assigned to 19 of the 22 ESI fields. The distribution of the papers among these 19 fields and the number of citations by field are presented in Table 1.
Table 1. Air Papers by ESI Fields
ESI Field |
No. of Citations |
No. of Air Papers |
Average Cites/Paper |
Biology & Biochemistry |
546 |
41 |
13.3 |
Chemistry |
2,375 |
150 |
15.8 |
Clinical Medicine |
6,479 |
260 |
24.9 |
Computer Science |
15 |
4 |
3.8 |
Economics & Business |
25 |
3 |
8.3 |
Engineering |
4,259 |
360 |
11.8 |
Environment/Ecology |
7,910 |
435 |
18.2 |
Geosciences |
8,477 |
490 |
17.3 |
Immunology |
377 |
14 |
26.9 |
Materials Science |
1 |
2 |
0.5 |
Mathematics |
35 |
7 |
5.0 |
Microbiology |
22 |
1 |
22.0 |
Molecular Biology & Genetics |
62 |
8 |
7.8 |
Multidisciplinary |
421 |
10 |
42.1 |
Neuroscience & Behavior |
227 |
20 |
11.4 |
Pharmacology & Toxicology |
2,951 |
220 |
13.4 |
Physics |
194 |
15 |
12.9 |
Plant & Animal Science |
124 |
11 |
11.3 |
Social Sciences, general |
62 |
13 |
4.8 |
|
Total = 34,562 |
Total = 2,064 |
16.7 |
There are 679 (32.9% of the papers analyzed) highly cited EPA air papers in 14 of the 19 fields—Biology & Biochemistry, Chemistry, Clinical Medicine, Economics & Business, Engineering, Environment/Ecology, Geosciences, Immunology, Mathematics, Multidisciplinary, Pharmacology & Toxicology, Physics, Plant & Animal Science, and Social Sciences—when using the ESI criteria for the top 10% of papers. Table 2 shows the number of EPA air papers in those 14 fields that meet the top 10% threshold in ESI. One hundred-seven (5.2%) of the papers analyzed qualify as highly cited when using the ESI criteria for the top 1% of papers. These papers cover 9 fields—Biology & Biochemistry, Chemistry, Clinical Medicine, Economics & Business, Engineering, Environment/ Ecology, Geosciences, Multidisciplinary, and Pharmacology & Toxicology. Table 3 shows the 107 (5.2% of the papers analyzed) papers by field that meet the top 1% threshold in ESI. The citations for these 107 papers are provided in Tables 4 through 12. Table 13 shows the 14 (0.7%) papers by field that meet the top 0.1% threshold in ESI. These 14 very highly cited air papers in the fields of Chemistry, Clinical Medicine, Economics & Business, Engineering, Environment/Ecology, and Geosciences are listed in Table 14. None of the air papers meet the top 0.01% threshold in ESI, which is not surprising because the expected number of papers that should meet this threshold for this analysis is 0.2. The highly cited papers in Tables 4 through 13 are presented in order of year of publication with the oldest papers appearing first. Within the year of publication, the papers are ordered by increasing number of times cited.
Table 2. Number of Highly Cited Air Papers by Field (top 10%)
ESI Field |
No. of Citations |
No. of Papers |
Average Cites/Paper |
% of Papers in Field |
Biology & Biochemistry |
216 |
6 |
36.0 |
14.6% |
Chemistry |
1,156 |
34 |
34.0 |
22.7% |
Clinical Medicine |
4,970 |
91 |
54.6 |
35.0% |
Economics & Business |
7 |
1 |
7.0 |
33.3% |
Engineering |
3,525 |
144 |
24.5 |
40.0% |
Environment/Ecology |
5,655 |
170 |
33.3 |
39.1% |
Geosciences |
5,737 |
164 |
35.0 |
33.5% |
Immunology |
303 |
5 |
60.6 |
35.7% |
Mathematics |
25 |
2 |
12.5 |
28.6% |
Multidisciplinary |
398 |
6 |
66.3 |
60.0% |
Pharmacology & Toxicology |
1,692 |
47 |
36.0 |
21.4% |
Physics |
117 |
3 |
39.0 |
20.0% |
Plant & Animal Science |
64 |
2 |
32.0 |
18.2% |
Social Sciences, general |
20 |
4 |
5.0 |
30.8% |
|
Total = 23,885 |
Total = 679 |
35.2 |
32.9% |
Table 3. Number of Highly Cited Air Papers by Field (top 1%)
ESI Field |
No. of Citations |
No. of Papers |
Average Cites/Paper |
% of Air Papers in Field |
Biology & Biochemistry |
37 |
1 |
37.0 |
2.4% |
Chemistry |
62 |
2 |
31.0 |
1.3% |
Clinical Medicine |
1,513 |
8 |
189.1 |
3.1% |
Economics & Business |
7 |
1 |
7.0 |
33.3% |
Engineering |
1,768 |
32 |
55.2 |
8.9% |
Environment/Ecology |
1,549 |
31 |
50.0 |
7.1% |
Geosciences |
2,255 |
28 |
80.5 |
5.7% |
Multidisciplinary |
272 |
2 |
136.0 |
20.0% |
Pharmacology & Toxicology |
259 |
2 |
129.5 |
0.9% |
|
Total = 7,722 |
Total = 107 |
72.2 |
5.2% |
Table 4. Highly Cited Air Papers in the Field of Biology & Biochemistry (top 1%)
No. of Cites |
ESI Threshold |
First Author |
Paper |
37 |
33 |
Kadiiska MB |
Biomarkers of Oxidative Stress Study II: are oxidation products of lipids, proteins, and DNA markers of CCl4 poisoning? Free Radical Biology & Medicine 2005;38(6):698-710. |
Table 5. Highly Cited Air Papers in the Field of Chemistry (top 1%)
No. of Cites |
ESI Threshold |
First Author |
Paper |
59 |
43 |
Gao S |
Low-molecular-weight and oligomeric components in secondary organic aerosol from the ozonolysis of cycloalkenes and alpha-pinene. Journal of Physical Chemistry A 2004;108(46):10147-10164. |
3 |
2 |
Rudich Y |
Aging of organic aerosol: bridging the gap between laboratory and field studies. Annual Review of Physical Chemistry 2007;58:321-352. |
Table 6. Highly Cited Air Papers in the Field of Clinical Medicine (top 1%)
No. of Cites |
ESI Threshold |
First Author |
Paper |
187 |
144 |
Abbey DE |
Long-term inhalable particles and other air pollutants related to mortality in nonsmokers. American Journal of Respiratory and Critical Care Medicine 1999;159(2):373-382. |
216 |
133 |
Gold DR |
Ambient pollution and heart rate variability. Circulation 2000;101(11):1267-1273. |
249 |
115 |
Peters A |
Increased particulate air pollution and the triggering of myocardial infarction. Circulation 2001;103(23):2810-2815. |
634 |
99 |
Pope CA |
Lung cancer, cardiopulmonary mortality and long-term exposure to fine particulate air pollution. Journal of the American Medical Association 2002;287(9):1132-1141. |
89 |
54 |
Peters A |
Exposure to traffic and the onset of myocardial infarction. New England Journal of Medicine 2004;351(17):1721-1730. |
131 |
54 |
Pope CA |
Cardiovascular mortality and long-term exposure to particulate air pollution: epidemiological evidence of general pathophysiological pathways of disease. Circulation 2004;109(1):71-77. |
2 |
2 |
Baccarelli A |
Effects of exposure to air pollution on blood coagulation. Journal of Thrombosis and Haemostasis 2007;5(2):252-260. |
5 |
2 |
Miller KA |
Long-term exposure to air pollution and incidence of cardiovascular events in women. New England Journal of Medicine 2007;356(5):447-458. |
Table 7. Highly Cited Air Papers in the Field of Economics & Business (top 1%)
No. of Cites |
ESI Threshold |
First Author |
Paper |
7 |
4 |
Peng RD |
Model choice in time series studies of air pollution and mortality. Journal of the Royal Statistical Society: Series A (Statistics in Society) 2006;169(2):179-203. |
Table 8. Highly Cited Air Papers in the Field of Engineering (top 1%)
No. of Cites |
ESI Threshold |
First Author |
Paper |
54 |
46 |
Zhang Y |
Simulation of aerosol dynamics: a comparative review of algorithms used in air quality models. Aerosol Science and Technology 1999;31(6):487-514. |
45 |
44 |
Wilson WE |
Estimating separately personal exposure to ambient and non-ambient particulate matter for epidemiology and risk assessment; why and how. Journal of the Air & Waste Management Association 2000;50(7):1167-1183. |
52 |
44 |
Tobias HJ |
Real-time chemical analysis of organic aerosols using a thermal desorption particle beam mass spectrometer. Aerosol Science and Technology 2000;33(1-2):170-190. |
75 |
44 |
Sarnat JA |
Assessing the relationship between personal particulate and gaseous exposures of senior citizens living in Baltimore. Journal of the Air & Waste Management Association 2000;50(7):1184-1198. |
78 |
44 |
Long CM |
Characterization of indoor particle sources using continuous mass and size monitors. Journal of the Air & Waste Management Association 2000;50(7):1236-1250. |
207 |
44 |
Jayne JT |
Development of an aerosol mass spectrometer for size and composition analysis of submicron particles. Aerosol Science and Technology 2000;33(1-2):49-70. |
209 |
44 |
Richter H |
Formation of polycyclic aromatic hydrocarbons and their growth to soot – |
38 |
37 |
Vette AF |
Characterization of indoor-outdoor aerosol concentration relationships during the Fresno PM exposure studies. Aerosol Science and Technology 2001;34(1):118-126. |
42 |
37 |
Lewtas J |
Comparison of sampling methods for semi-volatile organic carbon associated with PM2.5. Aerosol Science and Technology 2001;34(1):9-22. |
57 |
37 |
Tolocka MP |
East versus West in the US: chemical characteristics of PM2.5 during the winter of 1999. Aerosol Science and Technology 2001;34(1):88-96. |
92 |
37 |
Woo KS |
Measurement of Atlanta aerosol size distributions: Observations of ultrafine particle events. Aerosol Science and Technology 2001;34(1):75-87. |
105 |
37 |
Weber RJ |
A particle-into-liquid collector for rapid measurement of aerosol bulk chemical composition. Aerosol Science and Technology 2001;35(3):718-727. |
31 |
31 |
Cabada JC |
Sources of atmospheric carbonaceous particulate matter in Pittsburgh, Pennsylvania. Journal of the Air & Waste Management Association 2002;52(6):732-741. |
34 |
31 |
Zhang Z |
Cyclic micron-size particle inhalation and deposition in a triple bifurcation lung airway model. Aerosol Science and Technology 2002;33(2):257-281. |
37 |
31 |
Kim S |
Size distribution and diurnal and seasonal trends of ultrafine particles in source and receptor sites of the Los Angeles basin. Journal of the Air & Waste Management Association 2002;52(3):297-307. |
40 |
31 |
Zhang X |
A numerical characterization of particle beam collimation by an aerodynamic lens-nozzle system: Part I. an individual lens or nozzle. Aerosol Science and Technology 2002;36(5):617-631. |
63 |
31 |
McMurray PH |
The relationship between mass and mobility for atmospheric particles: A new technique for measuring particle density. Aerosol Science and Technology 2002;36(2):227-238. |
130 |
31 |
Zhu YF |
Concentration and size distribution of ultrafine particles near a major highway. Journal of the Air & Waste Management Association 2002;52(9):1032-1042. |
31 |
25 |
Lewis CW |
Source apportionment of Phoenix PM2.5 aerosol with the Unmix receptor model. Journal of the Air & Waste Management Association 2003;53(3):325-338. |
22 |
18 |
Lemieux PM |
Emissions of organic air toxics from open burning: a comprehensive review. Progress in Energy and Combustion Science 2004;30(1):1-32. |
23 |
18 |
Zhang XF |
Numerical characterization of particle beam collimation: Part II integrated aerodynamic-lens-nozzle system. Aerosol Science and Technology 2004;38(6):619-638. |
23 |
18 |
Zhu Y |
Seasonal trends of concentration and size distribution of ultrafine particles near major highways in Los Angeles. Aerosol Science and Technology 2004;38(S1):5-13. |
24 |
18 |
Cabada JC |
Estimating the secondary organic aerosol contribution to PM2.5 using the EC tracer method. Aerosol Science and Technology 2004;38(S1):140-155. |
25 |
18 |
Drewnick F |
Measurement of ambient aerosol composition during the PMTACS-NY 2001 campaign using an aerosol mass spectrometer. Part II: Chemically speciated mass distribution. Aerosol Science and Technology 2004;38(S1):104-117. |
26 |
18 |
Cho A |
Determination of four quinones in diesel exhaust particles, SRM 1649a and atmospheric PM2.5. Aerosol Science and Technology 2004;38(S1):68-81. |
33 |
18 |
Stanier CO |
Nucleation events during the Pittsburgh Air Quality Study: description and relation to key meteorological, gas phase, and aerosol parameters. Aerosol Science and Technology 2004;38(S1):253-264. |
34 |
18 |
Drewnick F |
Measurement of ambient aerosol composition during the PMTACS-NY 2001 campaign using an aerosol mass spectrometer. Part I: Mass concentrations. Aerosol Science and Technology 2004;38(S1):92-103. |
39 |
18 |
Subramanian R |
Positive and negative artifacts in particulate organic carbon measurements with denuded and undenuded sampler configurations. Aerosol Science and Technology 2004;38(S1):27-48. |
55 |
18 |
Canagaratna M |
Chase studies of particulate emissions from in-use New York City vehicles. Aerosol Science and Technology 2004;38(6):555-573. |
13 |
10 |
Kim E |
Estimation of organic carbon blank values and error structures of the speciation trends network data for source apportionment. Journal of the Air & Waste Management Association 2005;55(8):1190-1199. |
14 |
4 |
Byun D |
Review of the governing equations, computational algorithms, and other components of the Models-3 Community Multiscale Air Quality (CMAQ) modeling system. Applied Mechanics Reviews 2006;59:51-77. |
17 |
4 |
Bond TC |
Light absorption by carbonaceous particles: an investigative review. Aerosol Science and Technology 2006;40(1):27-67. |
Table 9. Highly Cited Air Papers in the Field of Environment/Ecology (top 1%)
No. of Cites |
ESI Threshold |
First Author |
Paper |
175 |
103 |
Liao D |
Daily variation of particulate air pollution and poor cardiac autonomic control in the elderly. Environmental Health Perspectives 1999;107(7):521-525. |
208 |
88 |
Laden F |
Association of fine particulate matter from different sources with daily mortality in six U.S. cities. Environmental Health Perspectives 2000;108(10):941-947. |
83 |
77 |
Fine PM |
Chemical characterization of fine particle emissions from the fireplace combustion of woods grown in the northeastern United States. Environmental Science & Technology 2001;35(13):2665-2675. |
83 |
77 |
Jang M |
Atmospheric secondary aerosol formation by heterogeneous reactions of aldehydes in the presence of a sulfuric acid aerosol catalyst. Environmental Science & Technology 2001;35(24):4758-4766. |
94 |
77 |
Dockery DW |
Epidemiologic evidence of cardiovascular effects of particulate air pollution. Environmental Health Perspectives 2001;109(S4):483-486. |
67 |
48 |
Park K |
Relationship between particle mass and mobility for diesel exhaust particles. Environmental Science & Technology 2003;37(3):577-583. |
144 |
48 |
Li N |
Ultrafine particulate pollutants induce oxidative stress and mitochondrial damage. Environmental Health Perspectives 2003;111(4):455-460. |
34 |
34 |
Landrigan PJ |
Health and environmental consequences of the World Trade Center disaster. Environmental Health Perspectives 2004;112(6):731-739. |
40 |
34 |
Chow JC |
Equivalence of elemental carbon by thermal/optical reflectance and transmittance with different temperature protocols. Environmental Science & Technology 2004;38(16):4414-4422. |
44 |
34 |
Xia T |
Quinones and aromatic chemical compounds in particulate matter induce mitochondrial dysfunction: implications for ultrafine particle toxicity. Environmental Health Perspectives 2004;112(14):1347-1358. |
45 |
34 |
Zhang Q |
Insights into the chemistry of new particle formation and growth events in Pittsburgh based on aerosol mass spectrometry. Environmental Science & Technology 2004;38(18):4797-4809. |
58 |
34 |
Pope CA |
Ambient particulate air pollution, heart rate variability, and blood markers of inflammation in a panel of elderly subjects. Environmental Health Perspectives 2004;112(3):339-345. |
59 |
34 |
Gao S |
Particle phase acidity and oligomer formation in secondary organic aerosol. Environmental Science & Technology 2004;38(24):6582-6589. |
17 |
17 |
Reisen F |
Atmospheric reactions influence seasonal PAH and nitro-PAH concentrations in the Los Angeles Basin. Environmental Science & Technology 2005;39(1):64-73. |
18 |
17 |
Delfino RJ |
Potential role of ultrafine particles in associations between airborne particle mass and cardiovascular health. Environmental Health Perspectives 2005;113(8):934-946. |
19 |
17 |
Dockery DW |
Association of air pollution with increased incidence of ventricular tachyarrhythmias recorded by implanted cardioverter defibrillators. Environmental Health Perspectives 2005;113(6):670-674. |
22 |
17 |
Zanobetti A |
The effect of particulate air pollution on emergency admissions for myocardial infarction: a multicity case-crossover analysis. Environmental Health Perspectives 2005;113(8):978-982. |
23 |
17 |
Lim H |
Isoprene forms secondary organic aerosol through cloud processing: model simulations. Environmental Science & Technology 2005;39(12):4441-4446. |
25 |
17 |
Park SK |
Effects of Air Pollution on Heart Rate Variability: The VA Normative Aging Study. Environmental Health Perspectives 2005;113(3):304-309. |
26 |
17 |
Bahreini R |
Measurements of secondary organic aerosol from oxidation of cycloalkenes, terpenes, and m-xylene using an Aerodyne aerosol mass spectrometer. Environmental Science & Technology 2005;39(15):5674-5688. |
27 |
17 |
Lough GC |
Emissions of metals associated with motor vehicle roadways. Environmental Science & Technology 2005;39(3):826-836. |
40 |
17 |
Zhang Q |
Deconvolution and quantification of hydrocarbon-like and oxygenated organic aerosols based on aerosol mass spectrometry. Environmental Science & Technology 2005;39(13):4938-4952. |
133 |
17 |
Oberdorster G |
Nanotoxicology: an emerging discipline evolving from studies of ultrafine particles. Environmental Health Perspectives 2005;113(7):823-839. |
6 |
6 |
Selgrade MK |
Induction of asthma and the environment: what we know and need to know. Environmental Health Perspectives 2006;114(4):615-619. |
7 |
6 |
Dubowsky SD |
Diabetes, obesity, and hypertension may enhance associations between air pollution and markers of systematic inflammation. Environmental Health Perspectives 2006;114(7):992-998. |
7 |
6 |
Elder A |
Translocation of inhaled ultrafine manganese oxide particles to the central nervous system. Environmental Health Perspectives 2006;114(8):1172-1178. |
7 |
6 |
Okin GS |
Multi-scale controls on and consequences of aeolian processes in landscape change in arid and semi-arid environments. Journal of Arid Environments 2006;65(2):253-275. |
8 |
6 |
Shrivastava MK |
Modeling semivolatile organic aerosol mass emissions from combustion systems. Environmental Science & Technology 2006;40(8):2671-2677. |
8 |
6 |
Donahue NM |
Coupled partitioning, dilution, and chemical aging of semivolatile organics. Environmental Science & Technology 2006;40(8):2635-2643. |
9 |
6 |
Presto AA |
Investigation of α-pinene + ozone secondary organic aerosol formation at low total aerosol mass. Environmental Science & Technology 2006;40(11):3536-3543. |
13 |
6 |
McConnell R |
Traffic, susceptibility, and childhood asthma. Environmental Health Perspectives 2006;114(5):766-772. |
Table 10. Highly Cited Air Papers in the Field of Geosciences (top 1%)
No. of Cites |
ESI Threshold |
First Author |
Paper |
116 |
114 |
Wang YH |
Global simulation of tropospheric O3-NOx-hydrocarbon chemistry, 2. Model evaluation. Journal of Geophysical Research–Atmospheres 1998;103(D9):10727-10756. |
148 |
114 |
Wang YH |
Global simulation of tropospheric O3-NOx-hydrocarbon chemistry, 1. Model formulation. Journal of Geophysical Research–Atmospheres 1998;103(D9):10713-10726. |
149 |
114 |
Nenes A |
ISORROPIA: a new thermodynamic equilibrium model for multiphase multicomponent inorganic aerosols. Aquatic Geochemistry 1998;4:123-152. |
121 |
98 |
Simpson D |
Inventorying emissions from nature in Europe. Journal of Geophysical Research–Atmospheres 1999;104(D7):8113-8152. |
166 |
98 |
Griffin RJ |
Organic aerosol formation from the oxidation of biogenic hydrocarbons. Journal of Geophysical Research–Atmospheres 1999;104(D3):3555-3567. |
170 |
98 |
Yu J |
Gas-Phase ozone oxidation of monoterpenes: gaseous and particulate products. Journal of Atmospheric Chemistry 1999;34(2):207-258. |
188 |
98 |
Simoneit BRT |
Levoglucosan, a tracer for cellulose in biomass burning and atmospheric particles. Atmospheric Environment 1999;33(2):173-182. |
112 |
85 |
Russell A |
NARSTO critical review of photochemical models and modeling. Atmospheric Environment 2000;34(12-14):2283-2324. |
130 |
85 |
Fuentes JD |
Biogenic hydrocarbons in the atmospheric boundary layer: a review. Bulletin of the American Meteorological Society 2000;81(7):1537-1575. |
174 |
85 |
Guenther A |
Natural emissions of non-methane volatile organic compounds, carbon monoxide, and oxides of nitrogen from North America. Atmospheric Environment 2000;34(12-14):2205-2230. |
92 |
69 |
Sokolik IN |
Introduction to special section: outstanding problems in quantifying the radiative impact of mineral dust. Journal of Geophysical Research–Atmospheres 2001;106(D16):18015-18027. |
178 |
69 |
Huser RB |
Asian dust events of April 1998. Journal of Geophysical Research– Atmospheres 2001;106(D16):18317-18330. |
121 |
54 |
Zhu Y |
Study of ultrafine particles near a major highway with heavy-duty diesel traffic. Atmospheric Environment 2002;36(27):4323-4335. |
42 |
41 |
Binkowski FS |
Models-3 Community Multiscale Air Quality (CMAQ) model aerosol component. 1. Model description. Journal of Geophysical Research– Atmospheres 2003;108(D6):4183. |
53 |
41 |
Orsini DA |
Refinements to the particle-into-liquid sampler (PILS) for ground and airborne measurements of water soluble aerosol composition. Atmospheric Environment 2003;37(9-10):243-1259. |
85 |
41 |
Jiminez JL |
Ambient aerosol sampling using the Aerodyne Aerosol Mass Spectrometer. Journal of Geophysical Research–Atmospheres 2003;108(D7):8425. |
29 |
29 |
Zhang KM |
Evolution of particle number distribution near roadways: Part II: The “road-to-ambient” process. Atmospheric Environment 2004;38(38):6655-6665. |
31 |
29 |
Wittig AE |
Pittsburgh Air Quality Study overview. Atmospheric Environment 2004;38(20):3107-3125. |
31 |
29 |
Kim E |
Improving source identification of Atlanta aerosol using temperature resolved carbon fractions in positive matrix factorization. Atmospheric Environment 2004;38(20):3349-3362. |
18 |
18 |
McKeen S |
Assessment of an ensemble of seven real-time ozone forecasts over eastern North America during the summer of 2004. Journal of Geophysical Research–Atmospheres 2005;110(D21307). |
27 |
18 |
Edney EO |
Formation of 2-methyl tetrols and 2-methylglyceric acid in secondary organic aerosol from laboratory irradiated isoprene/NOx/SO2/air mixtures and their detection in ambient PM2.5 samples collected in the eastern United States. Atmospheric Environment 2005;39(29):5281-5289. |
32 |
18 |
Zhang Q |
Hydrocarbon-like and oxygenated organic aerosols in Pittsburgh: insights into sources and processes or organic aerosols. Atmospheric Chemistry and Physics 2005;5(12):3289-3311. |
8 |
7 |
Hallock-Waters KA |
Carbon monoxide in the U. S. Mid-Atlantic troposphere: evidence for a decreasing trend. Geophysical Research Letters 2006;26(18):2861-2864. |
8 |
7 |
Offenberg JH |
Thermal properties of secondary organic aerosols. Geophysical Research Letters 2006;33(3):L03816. |
8 |
7 |
Takegawa N |
Seasonal and diurnal variations of submicron organic aerosol in Tokyo observed using the Aerodyne aerosol mass spectrometer. Journal of Geophysical Research–Atmospheres 2006;111(D11206). |
12 |
7 |
Guenther A |
Estimates of global terrestrial isoprene emissions using MEGAN (Model of Emissions of Gases and Aerosols from Nature). Journal of Geophysical Research–Atmospheres 2006;6:3181-3210. |
3 |
3 |
Kondo Y |
Oxygenated and water-soluble organic aerosols in Tokyo. Journal of Geophysical Research–Atmospheres 2007;112(D1):D01203. |
3 |
3 |
Pathak RK |
Ozonolysis of a-pinene at atmospherically relevant concentrations: Temperature dependence of aerosol mass fractions (yields). Journal of Geophysical Research–Atmospheres 2007;112(D3):D03201. |
Table 11. Highly Cited Air Papers in the Field of Multidisciplinary (top 1%)
No. of Cites |
ESI Threshold |
First Author |
Paper |
117 |
55 |
Gard EE |
Direct Observation of Heterogeneous Chemistry in the Atmosphere. Science 1998;279(5354):1184-1187. |
155 |
93 |
Jang M |
Heterogeneous Atmospheric Aerosol Production by Acid-Catalyzed Particle-Phase Reactions. Science 2002;298(5594):814-817. |
Table 12. Highly Cited Air Papers in the Field of Pharmacology & Toxicology (top 1%)
No. of Cites |
ESI Threshold |
First Author |
Paper |
157 |
99 |
Oberdorster G |
Pulmonary effects of inhaled ultrafine particles. International Archives of Occupational and Environmental Health 2001;74(1):1-8. |
102 |
44 |
Oberdorster G |
Translocation of inhaled ultrafine particles to the brain. Inhalation Toxicology 2004;16(6-7):437-445. |
Table 13. Number of Very Highly Cited Papers by Field (Top 0.1%)
ESI Field |
No. of Citations |
No. of Papers |
Average Cites/Paper |
% of Air Papers in Field |
Chemistry |
3 |
1 |
3.0 |
0.7% |
Clinical Medicine |
639 |
2 |
319.5 |
0.8% |
Economics & Business |
7 |
1 |
7.0 |
33.3% |
Engineering |
671 |
7 |
95.8 |
1.9% |
Environment/Ecology |
277 |
2 |
138.5 |
0.5% |
Geosciences |
178 |
1 |
178.0 |
0.2% |
|
Total = 1,775 |
Total = 14 |
126.8 |
0.7% |
Table 14. Very Highly Cited Air Papers (top 0.1%)
ESI Field |
ESI Threshold |
No. of Cites |
First Author |
Paper |
Chemistry |
3 |
3 |
Rudich Y |
Aging of organic aerosol: bridging the gap between laboratory and field studies. Annual Review of Physical Chemistry 2007;58:321-352. |
Clinical Medicine |
288 |
634 |
Pope CA |
Lung cancer, cardiopulmonary mortality and long-term exposure to fine particulate air pollution. Journal of the American Medical Association 2002;287(9):1132-1141. |
|
4 |
5 |
Miller KA |
Long-term exposure to air pollution and incidence of cardiovascular events in women. New England Journal of Medicine 2007;356(5):447-458. |
Economics & Business |
7 |
7 |
Peng RD |
Model choice in time series studies of air pollution and mortality. Journal of the Royal Statistical Society: Series A (Statistics in Society) 2006;169(2):179-203. |
Engineering |
116 |
207 |
Jayne JT |
Development of an aerosol mass spectrometer for size and composition analysis of submicron particles. Aerosol Science and Technology 2000;33(1-2):49-70. |
|
116 |
209 |
Richter H |
Formation of polycyclic aromatic hydrocarbons and their growth to soot – a review of chemical reaction pathways. Progress in Energy and Combustion Science 2000;26(4-6):565-608. |
|
76 |
130 |
Zhu YF |
Concentration and size distribution of ultrafine particles near a major highway. Journal of the Air & Waste Management Association 2002;52(9):1032-1042. |
|
39 |
39 |
Subramanian R |
Positive and negative artifacts in particulate organic carbon measurements with denuded and undenuded sampler configurations. Aerosol Science and Technology 2004;38(S1):27-48. |
|
39 |
55 |
Canagaratna M |
Chase studies of particulate emissions from in-use New York City vehicles. Aerosol Science and Technology 2004;38(6):555-573. |
|
9 |
14 |
Byun D |
Review of the governing equations, computational algorithms, and other components of the Models-3 Community Multiscale Air Quality (CMAQ) modeling system. Applied Mechanics Reviews 2006;59:51-77. |
|
9 |
17 |
Bond TC |
Light absorption by carbonaceous particles: an investigative review. Aerosol Science and Technology 2006;40(1):27-67. |
Environment/ Ecology |
116 |
144 |
Li N |
Ultrafine particulate pollutants induce oxidative stress and mitochondrial damage. Environmental Health Perspectives 2003;111(4):455-460. |
|
43 |
133 |
Oberdorster G |
Nanotoxicology: an emerging discipline evolving from studies of ultrafine particles. Environmental Health Perspectives 2005;113(7):823-839. |
Geosciences |
176 |
178 |
Huser RB |
Asian dust events of April 1998. Journal of Geophysical Research–Atmospheres 2001;106(D16):18317-18330. |
Ratio of Actual Cites to Expected Citation Rates
The expected citation rate is the average number of cites that a paper published in the same journal in the same year and of the same document type (article, review, editorial, etc.) has received from the year of publication to the present. Using the ESI average citation rates for papers published by field as the benchmark, in 15 of the 19 fields in which the EPA air papers were published, the ratio of actual to expected cites is greater than 1, indicating that the air papers are more highly cited than the average papers in those fields (see Table 15). For one field, the ratio is equal to 1, indicating that the papers in that ESI field are cited the same as the average paper. For all 19 fields combined, the ratio of total number of cites to the total number of expected cites (34,562 to 15,305.25) is 2.2, indicating that the air papers are more highly cited than the average paper.
Table 15. Ratio of Actual Cites to Expected Cites for Air Papers by Field
ESI Field |
Total Cites |
Expected Cite Rate |
Ratio |
Biology & Biochemistry |
546 |
570.96 |
1.0 |
Chemistry |
2,375 |
1,476.02 |
1.6 |
Clinical Medicine |
6,479 |
2,404.04 |
2.7 |
Computer Science |
15 |
14.06 |
1.1 |
Economics & Business |
25 |
7.29 |
3.4 |
Engineering |
4,259 |
1,178.88 |
3.6 |
Environment/Ecology |
7,910 |
3,299.45 |
2.4 |
Geosciences |
8,477 |
3,378.05 |
2.5 |
Immunology |
377 |
225.52 |
1.7 |
Materials Science |
1 |
9.72 |
0.1 |
Mathematics |
35 |
15.00 |
2.3 |
Microbiology |
22 |
20.07 |
1.1 |
Molecular Biology & Genetics |
62 |
202.11 |
0.3 |
Multidisciplinary |
421 |
42.32 |
9.9 |
Neuroscience & Behavior |
227 |
330.78 |
0.7 |
Pharmacology & Toxicology |
2,951 |
1,868.21 |
1.6 |
Physics |
194 |
138.43 |
1.4 |
Plant & Animal Science |
124 |
88.47 |
1.4 |
Social Sciences, general |
62 |
35.87 |
1.7 |
TOTAL |
34,562 |
15,305.25 |
2.2 |
JCR Benchmarks
Impact Factor. The JCR Impact Factor is a well known metric in citation analysis. It is a measure of the frequency with which the “average article” in a journal has been cited in a particular year. The Impact Factor helps evaluate a journal’s relative importance, especially when compared to others in the same field. The Impact Factor is calculated by dividing the number of citations in the current year to articles published in the 2 previous years by the total number of articles published in the 2 previous years.
Table 16 indicates the number of air papers published in the top 10% of journals, based on the JCR Impact Factor. Six hundred ninety-six (696) of 2,064 papers were published in the top 10% of journals, representing 33.7% of EPA’s air papers. This indicates that more than one-third of the air papers are published in the highest quality journals as determined by the JCR Impact Factor, which is 3.4 times higher than the expected percentage.
Table 16. Air Papers in Top 10% of Journals by JCR Impact Factor
EPA Air Papers in that Journal |
Journal |
Impact Factor |
JCR IF Rank |
2 |
New England Journal of Medicine |
51.296 |
2 |
7 |
Science |
30.028 |
9 |
3 |
Lancet |
25.800 |
18 |
5 |
JAMA—Journal of the American Medical Association |
23.175 |
23 |
1 |
Journal of Clinical Investigation |
15.754 |
42 |
1 |
Annual Review of Physical Chemistry |
11.250 |
83 |
10 |
Circulation |
10.940 |
88 |
1 |
Nano Letters |
9.960 |
110 |
2 |
Proceedings of the National Academy of Sciences of the United States of America |
9.643 |
116 |
27 |
American Journal of Respiratory and Critical Care Medicine |
9.091 |
131 |
7 |
Journal of Allergy and Clinical Immunology |
8.829 |
136 |
1 |
Neuroscience & Biobehavioral Reviews |
8.293 |
149 |
1 |
Advanced Drug Delivery Reviews |
7.977 |
156 |
1 |
Journal of the American Chemical Society |
7.696 |
168 |
2 |
Cancer Research |
7.656 |
172 |
1 |
Mutation Research–Reviews in Mutation Research |
7.579 |
175 |
1 |
Journal of Neuroscience |
7.453 |
177 |
1 |
FASEB Journal |
6.721 |
206 |
1 |
Critical Care Medicine |
6.599 |
211 |
5 |
Journal of Immunology |
6.293 |
223 |
1 |
Plant Physiology |
6.125 |
232 |
5 |
Thorax |
6.064 |
237 |
1 |
American Journal of Pathology |
5.917 |
249 |
130 |
Environmental Health Perspectives |
5.861 |
255 |
4 |
Journal of Biological Chemistry |
5.808 |
260 |
14 |
Analytical Chemistry |
5.646 |
276 |
6 |
Free Radical Biology & Medicine |
5.440 |
289 |
1 |
Stroke |
5.391 |
293 |
12 |
American Journal of Epidemiology |
5.241 |
308 |
1 |
Journal of Thrombosis and Haemostasis |
5.138 |
325 |
4 |
European Respiratory Journal |
5.076 |
335 |
2 |
TrAC - Trends in Analytical Chemistry |
5.068 |
337 |
1 |
Cellular Signaling |
4.887 |
363 |
1 |
Faraday Discussions |
4.731 |
393 |
27 |
Toxicology and Applied Pharmacology |
4.722 |
397 |
1 |
Environmental Microbiology |
4.630 |
406 |
18 |
American Journal of Respiratory Cell and Molecular Biology |
4.593 |
412 |
1 |
Journal of Leukocyte Biology |
4.572 |
415 |
5 |
Journal of Catalysis |
4.533 |
418 |
1 |
International Journal of Epidemiology |
4.517 |
424 |
1 |
Antioxidants & Redox Signaling |
4.491 |
431 |
2 |
Atmospheric Chemistry and Physics |
4.362 |
449 |
24 |
Epidemiology |
4.339 |
452 |
2 |
American Journal of Physiology - Cell Physiology |
4.334 |
455 |
3 |
Progress in Energy and Combustion Science |
4.333 |
456 |
1 |
Cancer Epidemiology Biomarkers & Prevention |
4.289 |
463 |
36 |
American Journal of Physiology - Lung Cellular and Molecular Physiology |
4.250 |
472 |
4 |
Journal of Physical Chemistry B |
4.115 |
501 |
2 |
Mutation Research–Fundamental and Molecular Mechanisms of Mutagenesis |
4.111 |
505 |
167 |
Environmental Science & Technology |
4.040 |
518 |
1 |
Journal of Pharmacology and Experimental Therapeutics |
3.956 |
545 |
2 |
Applied Catalysis B: Environmental |
3.942 |
548 |
3 |
Chest |
3.924 |
552 |
1 |
Carbon |
3.884 |
562 |
1 |
Experimental Cell Research |
3.777 |
596 |
1 |
Human Reproduction |
3.769 |
599 |
5 |
Bulletin of the American Meteorological Society |
3.728 |
614 |
1 |
American Journal of Physiology - Heart and Circulatory Physiology |
3.724 |
616 |
1 |
American Journal of Public Health |
3.698 |
626 |
1 |
Journal of Cellular Physiology |
3.638 |
646 |
3 |
Clinical Immunology |
3.606 |
659 |
1 |
Optics Letters |
3.598 |
662 |
41 |
Toxicological Sciences |
3.598 |
662 |
1 |
Biochemical Pharmacology |
3.581 |
667 |
1 |
Genomics |
3.558 |
676 |
4 |
Journal of Chromatography A |
3.554 |
678 |
3 |
Journal of Neuroscience Research |
3.476 |
704 |
1 |
Ecological Applications |
3.470 |
708 |
1 |
Cancer Letters |
3.277 |
777 |
15 |
Journal of Applied Physiology |
3.178 |
807 |
2 |
Journal of Chemical Physics |
3.166 |
814 |
8 |
Chemical Research in Toxicology |
3.162 |
818 |
1 |
Remote Sensing of Environment |
3.064 |
855 |
38 |
Journal of Physical Chemistry A |
3.047 |
863 |
1 |
American Journal of Cardiology |
3.015 |
876 |
Total = 696 |
|
|
|
Immediacy Index. The JCR Immediacy Index is a measure of how quickly the average article in a journal is cited. It indicates how often articles published in a journal are cited within the year they are published. The Immediacy Index is calculated by dividing the number of citations to articles published in a given year by the number of articles published in that year.
Table 17 indicates the number of air papers published in the top 10% of journals, based on the JCR Immediacy Index. Nine hundred sixty-six (966) of the 2,064 papers appear in the top 10% of journals, representing 46.8% of the air papers. This indicates that nearly one-half of the air papers are published in the highest quality journals as determined by the JCR Immediacy Index, which is 4.7 times higher than the expected percentage.
Table 17. Air Papers in Top 10% of Journals by JCR Immediacy Index
EPA Air Papers in that Journal |
Journal |
Immediacy Index |
JCR II Rank |
2 |
New England Journal of Medicine |
12.743 |
2 |
5 |
JAMA - Journal of the American Medical Association |
7.781 |
4 |
3 |
Lancet |
7.419 |
6 |
7 |
Science |
5.555 |
16 |
1 |
Journal of Clinical Investigation |
3.911 |
29 |
1 |
Faraday Discussions |
2.766 |
59 |
10 |
Circulation |
2.674 |
63 |
1 |
International Journal of Epidemiology |
2.200 |
84 |
27 |
American Journal of Respiratory and Critical Care Medicine |
2.006 |
98 |
7 |
Journal of Allergy and Clinical Immunology |
1.790 |
118 |
1 |
Annual Review of Physical Chemistry |
1.762 |
124 |
2 |
Proceedings of the National Academy of Sciences of the United States of America |
1.758 |
126 |
1 |
Critical Care Medicine |
1.641 |
146 |
4 |
Philosophical Transactions of the Royal Society of London Series A: Mathematical and Physical Sciences |
1.534 |
166 |
1 |
Journal of the American Chemical Society |
1.510 |
168 |
1 |
Nano Letters |
1.485 |
177 |
5 |
Thorax |
1.460 |