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Nitrogen dioxide (CASRN 10102-44-0)
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0080
Nitrogen dioxide;
CASRN 10102-44-0
Health assessment information on a chemical substance is included in IRIS
only after a comprehensive review of chronic toxicity data by U.S. EPA
health scientists from several Program Offices and the Office of Research
and Development. The summaries presented in Sections I and II represent
a consensus reached in the review process. Background information and
explanations of the methods used to derive the values given in IRIS are
provided in the Background Documents.
STATUS OF DATA FOR Nitrogen dioxide
File First On-Line 01/31/1987
Category (section) |
Status |
Last Revised |
|---|---|---|
| Oral RfD Assessment (I.A.) | withdrawn | 09/01/1994 |
| Inhalation RfC Assessment (I.B.) | message | 02/01/1993 |
| Carcinogenicity Assessment (II.) | no data | 10/01/1991 |
_I. Chronic Health Hazard Assessments for Noncarcinogenic Effects
_I.A. Reference Dose for Chronic Oral Exposure (RfD)
Substance Name — Nitrogen dioxide
CASRN — 10102-44-0
The RfD for nitrogen dioxide has been withdrawn from IRIS as of 09/01/1994 based on the fact that nitrogen dioxide does not exist per se in water, since it reacts instantaneously with water to form nitric and nitrous acids (U.S. EPA, 1993).
In the presence of alkali (pH > 7.0), nitrates and nitrites are formed, respectively, from nitric and nitrous acids. RfDs presently exist for nitrates and nitrites. As more fully explained on the IRIS files for those chemicals, the critical effect is the formation of methemoglobin resulting from the oxidation of the ferrous iron (+2) in hemoglobin to ferric iron (+3). The inability of methemoglobin to combine with oxygen results in clinical effects due to tissue hypoxia.
U.S. EPA. 1993. Air Quality Criteria for Oxides of Nitrogen. Office of Health and Environmental Assessment, Environmental Criteria and Assessment Office, Research Triangle Park, NC. EPA-600/8-91/049aF.
Agency Work Group Review — 08/19/1985, 02/26/1986, 06/24/1992, 08/04/1994
EPA Contacts:
Please contact the IRIS Hotline for all questions concerning this assessment or IRIS, in general, at (202)566-1676 (phone), (202)566-1749 (FAX) or hotline.iris@epa.gov (internet address).
Screening-Level Literature Review Findings — A screening-level review conducted by an EPA contractor of the more recent toxicology literature pertinent to the RfD for nitrogen dioxide conducted in August 2003 did not identify any critical new studies. IRIS users who know of important new studies may provide that information to the IRIS Hotline at hotline.iris@epa.gov or 202-566-1676.
_I.B. Reference Concentration for Chronic Inhalation Exposure (RfC)
Substance Name — Nitrogen dioxide
CASRN — 10102-44-0
An inhalation RfC will not be derived for nitrogen dioxide because a National Ambient Air Quality Standard (NAAQS) is available.
Agency Work Group Review — 09/19/1989
EPA Contacts:
Please contact the IRIS Hotline for all questions concerning this assessment or IRIS, in general, at (202)566-1676 (phone), (202)566-1749 (FAX) or hotline.iris@epa.gov (internet address).
_II. Carcinogenicity Assessment for Lifetime Exposure
Substance Name — Nitrogen dioxide
CASRN — 10102-44-0
Not available at this time.
_III.
[reserved]
_IV. [reserved]
_V. [reserved]
_VI. Bibliography
Substance Name — Nitrogen dioxide
CASRN — 10102-44-0
Last Revised — 09/01/1994
_VI.A. Oral RfD References
U.S. EPA. 1993. Air Quality Criteria for Oxides of Nitrogen. Office of Health and Environmental Assessment, Environmental Criteria and Assessment Office, Research Triangle Park, NC. EPA-600/8-91/049aF.
_VI.B. Inhalation RfC References
None
_VI.C. Carcinogenicity Assessment References
None
_VII. Revision History
Substance Name — Nitrogen dioxide
CASRN — 10102-44-0
| Date |
Section |
Description |
|---|---|---|
| 03/31/1987 | I.A.6. | Documentation corrected |
| 10/01/1989 | I.B. | Inhalation RfD now under review |
| 08/01/1991 | I.A. | Oral RfD summary noted as pending change |
| 10/01/1991 | II. | Carcinogenicity assessment now under review |
| 01/01/1992 | I.A.7. | Primary contact changed |
| 01/01/1992 | IV. | Regulatory actions updated |
| 07/01/1992 | I.A.2. | Last paragraph deleted |
| 07/01/1992 | VI.A. | Oral RfD references on-line |
| 02/01/1993 | I.B. | No RfC in lieu of regulatory standard |
| 09/01/1994 | I.A. | RfD withdrawn; replaced with permanent withdrawal msg |
| 09/01/1994 | VI.A. | Oral RfD references revised |
| 08/01/1995 | II. | EPA's RfD/RfC and CRAVE workgroups were discontinued in May, 1995. Chemical substance reviews that were not completed by September 1995 were taken out of IRIS review. The IRIS Pilot Program replaced the workgroup functions beginning in September, 1995. |
| 04/01/1997 | III., IV., V. | Drinking Water Health Advisories, EPA Regulatory Actions, and Supplementary Data were removed from IRIS on or before April 1997. IRIS users were directed to the appropriate EPA Program Offices for this information. |
| 10/28/2003 | I.A. | Screening-Level Literature Review Findings message has been added. |
_VIII. Synonyms
Substance Name — Nitrogen dioxide
CASRN — 10102-44-0
Last Revised — 01/31/1987
- 10102-44-0
- Nitrito
- Nitro
- Nitrogen Dioxide
- Nitrogen Oxide
- Nitrogen Peroxide
- Nitrogen Tetroxide