Indoor nitrous acid and respiratory symptoms and lung function in adults

D L Jarvis, B P Leaderer, S Chinn, P G Burney

Research output: Contribution to journalArticlepeer-review

56 Citations (Scopus)


BACKGROUND: Nitrogen dioxide (NO(2)) is an important pollutant of indoor and outdoor air, but epidemiological studies show inconsistent health effects. These inconsistencies may be due to failure to account for the health effects of nitrous acid (HONO) which is generated directly from gas combustion and indirectly from NO(2). METHODS: Two hundred and seventy six adults provided information on respiratory symptoms and lung function and had home levels of NO(2) and HONO measured as well as outdoor levels of NO(2). The association of indoor HONO levels with symptoms and lung function was examined. RESULTS: The median indoor HONO level was 3.10 ppb (IQR 2.05-5.09), with higher levels in homes with gas hobs, gas ovens, and in those measured during the winter months. Non-significant increases in respiratory symptoms were observed in those living in homes with higher HONO levels. An increase of 1 ppb in indoor HONO was associated with a decrease in forced expiratory volume in 1 second (FEV(1)) percentage predicted (-0.96%; 95% CI -0.09 to -1.82) and a decrease in percentage FEV(1)/forced vital capacity (FVC) (-0.45%; 95% CI -0.06 to -0.83) after adjustment for relevant confounders. Measures of indoor NO(2) were correlated with HONO (r = 0.77), but no significant association of indoor NO(2) with symptoms or lung function was observed. After adjustment for NO(2) measures, the association of HONO with low lung function persisted. CONCLUSION: Indoor HONO levels are associated with decrements in lung function and possibly with more respiratory symptoms. Inconsistencies between studies examining health effects of NO(2) and use of gas appliances may be related to failure to account for this association.
Original languageEnglish
Pages (from-to)474 - 479
Number of pages6
Issue number6
Publication statusPublished - Jun 2005


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