Time-Resolved Measurements of Nitric Oxide, Nitrogen Dioxide, and Nitrous Acid in an Occupied New York Home

Abstract

Indoor oxidizing capacity in occupied residences is poorly understood. We made simultaneous continuous time-resolved measurements of ozone (O), nitric oxide (NO), nitrogen dioxide (NO), and nitrous acid (HONO) for two months in an occupied detached home with gas appliances in Syracuse, NY. Indoor NO and HONO mixing ratios were higher than those outdoors, whereas O was much lower (sub-ppbv) indoors. Cooking led to peak NO, NO, and HONO levels 20-100 times greater than background levels; HONO mixing ratios of up to 50 ppbv were measured. Our results suggest that many reported NO levels may have a large positive bias due to HONO interference. Nitrous acid, NO, and NO were removed from indoor air more rapidly than CO, indicative of reactive removal processes or surface uptake. We measured spectral irradiance from sunlight entering the residence through glass doors; hydroxyl radical (OH) production rates of (0.8-10) × 10 molecules cm s were calculated in sunlit areas due to HONO photolysis, in some cases exceeding rates expected from ozone-alkene reactions. Steady-state nitrate radical (NO) mixing ratios indoors were predicted to be lower than 1.65 × 10 molecules cm. This work will help constrain the temporal nature of oxidant concentrations in occupied residences and will improve indoor chemistry models.

Isotopic characterization of nitrogen oxides (NO<sub>x</sub>), nitrous acid (HONO), and nitrate (NO<sub>3</sub><sup>−</sup>(p)) from laboratory biomass burning during FIREX

“…containing species that could be trapped and form nitrite in residual amounts on the 178 denuders, especially NO 2 . Our method development study showed NO 2 tends to absorb in 179 the same amount (difference <4%) on the walls of each denuder in a train setup, which is 180 consistent with other studies (Perrino et al, 1990;Zhou et al, 2018). On the basis of this 181 validation, the second denuder extract is used to correct the first denuder extract for both 182 concentration and isotopic composition .…”

Indoor boundary layer chemistry modeling

“…The range of photolysis rate constants due to indoor illumination sources ranges from very small for LEDs to 1.3 × 10 −5 /s 1 m from a bare fluorescent bulb . A typical indoor HONO concentration is about 5‐10 ppb but can rise as high as 50 ppb during cooking . HONO photolysis raises the OH concentration by 3 × 10 4 molec/(cm 2 s), 1 m from a fluorescent bulb with a background HONO mixing ratio of 5 ppb.…”

Predicting the importance of oxidative aging on indoor organic aerosol concentrations using the two‐dimensional volatility basis set (2D‐ VBS )

“…Indoors, background levels of HONO may persist due to equilibrium between the gas‐phase and reservoirs on indoor surfaces . Higher HONO levels are caused by indoor combustion activities such as cooking with a gas stove . The indoor photolysis rate constant of HONO ( J ) under attenuated sunlight has been measured to be 1.26 × 10 −4 s −1 .…”

“…The indoor photolysis rate constant of HONO ( J ) under attenuated sunlight has been measured to be 1.26 × 10 −4 s −1 . Using indoor HONO measurements from Zhou et al . and the AER and assumed photolysis distributions described in Table , the distribution describing the total effective emission rate of HONO ([ E / V ] HONO , due to the combined time‐averaged processes of combustion and background evaporation from surfaces) was generated.…”

“…51 Higher HONO levels are caused by indoor combustion activities such as cooking with a gas stove. 34,52 The indoor photolysis rate constant of HONO (J) under attenuated sunlight has been measured to be 1.26 × 10 −4 s −1 . 53 Using indoor HONO measurements from Zhou et al 52 and the AER and assumed photolysis distributions described…”