Reactive nitrogen species influence the chemistry of indoor and outdoor atmospheres. The wide range of nitrogen oxidation states enables reactive nitrogen to behave as a catalyst for the degradation of air quality through ozone production, form respirable particulate matter, and kick-start free radical oxidation under low light conditions. Their quantitative determination is challenging as their ambient levels may be low (parts per trillion to parts per quadrillion), susceptible to rapid chemical change, and methodological interferences. Recent attention to reactive nitrogen chemistry occurring indoors has revealed further vulnerabilities in transitioning state-of-the-science outdoor analytical approaches to this environment. Our team has designed new calibration sources and molecular probes for the quantitation of nitrous acid (HONO), is conducting a survey of new Canadian homes for reduced nitrogen levels and constructing an automated real-time analyzer that simplifies our surveying reactive nitrogen in indoor air.