Missing gas-phase source of HONO inferred from Zeppelin measurements in the troposphere.
نویسندگان
چکیده
Gaseous nitrous acid (HONO) is an important precursor of tropospheric hydroxyl radicals (OH). OH is responsible for atmospheric self-cleansing and controls the concentrations of greenhouse gases like methane and ozone. Due to lack of measurements, vertical distributions of HONO and its sources in the troposphere remain unclear. Here, we present a set of observations of HONO and its budget made onboard a Zeppelin airship. In a sunlit layer separated from Earth's surface processes by temperature inversion, we found high HONO concentrations providing evidence for a strong gas-phase source of HONO consuming nitrogen oxides and potentially hydrogen oxide radicals. The observed properties of this production process suggest that the generally assumed impact of HONO on the abundance of OH in the troposphere is substantially overestimated.
منابع مشابه
ATMOSPHERIC SCIENCE. Response to Comment on "Missing gas-phase source of HONO inferred from Zeppelin measurements in the troposphere".
Ye et al. have determined a maximum nitrous acid (HONO) yield of 3% for the reaction HO2·H2O + NO2, which is much lower than the yield used in our work. This finding, however, does not affect our main result that HONO in the investigated Po Valley region is mainly from a gas-phase source that consumes nitrogen oxides.
متن کاملResponse to Comment on “Missing gas-phase source of HONO inferred from Zeppelin measurements in the troposphere”
T he self-cleansing capacity of the atmosphere is largely dependent on the concentration level of hydroxyl radicals (OH) (1). Nitrous acid (HONO) is an important precursor of OH in the troposphere (2–4). Based on observations of HONO and its budget in the Po Valley region in Italy, we concluded that HONO formation in a sunlit layer separated from the ground surface is from a gas-phase source co...
متن کاملOn the interpretation of in situ HONO observations via photochemical steady state.
A substantial body of recent literature has shown that boundary layer HONO levels are higher than can be explained by simple, established gas-phase chemistry, to an extent that implies that additional HONO sources represent a major, or the dominant, precursor to OH radicals in such environments. This conclusion may be reached by analysis of point observations of (for example) OH, NO and HONO, a...
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[1] Nitrous acid is an important precursor for OH radicals in the polluted troposphere. The heterogeneous conversion of NO2 to HONO, however, is currently not well understood. Measurements of HONO and NO2 in Phoenix in summer 2001 using long path DOAS show ratios of chemically formed secondary [HONO] to [NO2] that rarely exceeded 3%. During two nocturnal dust storm events, however, a significan...
متن کامل1-D air-snowpack modeling of atmospheric nitrous acid at South Pole during ANTCI 2003
Introduction Conclusions References Tables Figures ◭ ◮ ◭ ◮ Back Close Full Screen / Esc Abstract Introduction Conclusions References Tables Figures ◭ ◮ ◭ ◮ Back Close Full Screen / Esc Abstract A 1-D air-snowpack model of HONO has been developed and constrained by observed chemistry and meteorology data. The 1-D model includes molecular diffusion and mechanical dispersion, windpumping in snow, ...
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عنوان ژورنال:
- Science
دوره 344 6181 شماره
صفحات -
تاریخ انتشار 2014