Heterogeneous conversion of NO2 on secondary organic aerosol surfaces: A possible source of nitrous acid (HONO) in the atmosphere?
نویسنده
چکیده
The heterogeneous conversion of NO2 on different secondary organic aerosols (SOA) was investigated with the focus on a possible formation of nitrous acid (HONO). In one set of experiments different organic aerosols were produced in the reactions of O3 with α-pinene, limonene or catechol and OH radicals with toluene or limonene, respectively. The aerosols were sampled on filters and exposed to humidified NO2 mixtures under atmospheric conditions. The estimated upper limits for the uptake coefficients of NO2 and the reactive uptake coefficients NO2→HONO are in the range of 10−6 and 10−7, respectively. The integrated HONO formation for 1 h reaction time was < 1013 cm−2 geometrical surface and < 1017 g−1 particle mass. In a second set of experiments the conversion of NO2 into HONO in the presence of organic particles was carried out in an aerosol flow tube under atmospheric conditions. In this case the aerosols were produced in the reaction of O3 with β-pinene, limonene or catechol, respectively. The upper limits for the reactive uptake coefficients NO2→HONO were in the range of 7× 10−7 − 9× 10−6. The results from the present study show that heterogeneous formation of nitrous acid on secondary organic aerosols (SOA) is unimportant for the atmosphere.
منابع مشابه
Heterogeneous conversion of NO2 on secondary organic aerosol surfaces
Heterogeneous conversion of NO2 on secondary organic aerosol surfaces: A possible source of nitrous acid (HONO) in the atmosphere? R. Bröske, J. Kleffmann, and P. Wiesen Physikalische Chemie/FB 9, Bergische Universität – Gesamthochschule Wuppertal (BUGHW), D-42097 Wuppertal, Germany Received: 18 November 2002 – Accepted: 6 January 2003 – Published: 7 February 2003 Correspondence to: J. Kleffman...
متن کاملReview of heterogeneous photochemical reactions of NOy on aerosol - A possible daytime source of nitrous acid (HONO) in the atmosphere.
As an important precursor of hydroxyl radical, nitrous acid (HONO) plays a key role in the chemistry of the lower atmosphere. Recent atmospheric measurements and model calculations show strong enhancement for HONO formation during daytime, while they are inconsistent with the known sources in the atmosphere, suggesting that current models are lacking important sources for HONO. In this article,...
متن کاملObservations of high rates of NO2-HONO conversion in the nocturnal atmospheric boundary layer in Kathmandu, Nepal
Nitrous acid (HONO) plays a significant role in the atmosphere, especially in the polluted troposphere. Its photolysis after sunrise is an important source of hydroxyl free radicals (OH). Measurements of nitrous acid and other pollutants were carried out in the Kathmandu urban atmosphere during January–February 2003, contributing to the sparse knowledge of nitrous acid in South Asia. The result...
متن کاملLight induced conversion of nitrogen dioxide into nitrous acid on submicron humic acid aerosol
The interactions of aerosols consisting of humic acids with gaseous nitrogen dioxide (NO2) were investigated under different light conditions in aerosol flow tube experiments at ambient pressure and temperature. The results show that NO2 is converted on the humic acid aerosol into nitrous acid (HONO), which is released from the aerosol and can be detected in the gas phase at the reactor exit. T...
متن کاملRelative humidity dependence of HONO chemistry in urban areas
[1] The role of nitrous acid, HONO, as a precursor for hydroxyl radicals in polluted urban air has been recognized for many years. The chemical processes leading to the formation of HONO are, however, still not well understood. Laboratory studies show that HONO formation occurs primarily on surfaces and is first order in NO2. Water also plays an important role in the conversion process. While t...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2003