Measurements of Nitrous Acid (HONO) mixing ratios and other compounds were made in the north-east periphery of the town of Ashdod (south of Tel Aviv, Israel) during two campaigns in the autumn of 2004 and the summer of 2005. This work was part of a bilateral Italian-Israeli cooperation on environmental technologies, project “Modeling system for urban air pollution”. Statistical analysis of the data shows an expected correlation between HONO and nitrogen oxides in the autumn campaign; the sources of HONO appear to be traffic, the harbor, and industry next to the sampling location. However, in the summer HONO and NO2 are no longer correlated: NO2 during nighttime is probably deposited onto soil and plants, while HONO during daytime is likely destroyed photolytically and contributes to the OH concentration. Photolysis is the dominant sink for HONO in daytime especially in the summer period when HONO is anti-correlated with the intensity of UV-B radiation.
Keywords: HONO, nitrous acid, atmospheric chemistry, air pollution, pollution sources; pollution processing; Israel.
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