A report from Health Canada reviews the toxicological data on nitrogen dioxide (NO2), the critical effect being respiratory symptoms in asthmatics. Health-based reference concentrations (RfCs) of 170 and 10 µg/m3 were derived for short-term (1-hour) and long-term (up to lifetime) exposures, respectively. Based on these values, and also taking into account technical feasibility, Health Canada calculated respective acute and chronic ‘proposed residential indoor air quality guidelines’ (PRIAQGs) of 170 and 20 μg/m3. Although the chronic PRIAQG is double the chronic RfC, “the epidemiological evidence is not suggestive of appreciable health effects associated with long‑term exposure at this concentration”, and Health Canada considers both the short- and long-term PRIAQGs to be health-protective.

Health Canada (2015). Proposed residential indoor air quality guideline: nitrogen dioxide. March 2015. http://www.hc-sc.gc.ca/ewh-semt/pubs/air/no2/index-eng.php#c4



The above items were taken from the July 2015 issue of Toxicology and Regulatory News which is sent automatically to members of bibra (click here)

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