Journal Article

Megacity Emissions and Lifetimes of Nitrogen Oxides Probed from Space

Boersma, K. Folkert, Wagner, Thomas, Beirle, Steffen, Lawrence, Mark G., Platt, Ulrich

2011

Overview

Megacities are immense sources of air pollutants, with large impacts on air quality and climate. However, emission inventories in many of them still are highly uncertain, particularly in developing countries. Satellite observations allow top-down estimates of emissions to be made for nitrogen oxides (NO x = NO + NO₂), but require poorly quantified a priori information on the NO x lifetime. We present a method for the simultaneous determination of megacity NO x emissions and lifetimes from satellite measurements by analyzing the downwind patterns of NO₂ separately for different wind conditions. Daytime lifetimes are ∼4 hours at low and mid-latitudes, but ∼8 hours in wintertime for Moscow. The derived NO x emissions are generally in good agreement with existing emission inventories, but are higher by a factor of 3 for the Saudi Arabian capital Riyadh.

• Publisher: American Association for the Advancement of Science,The American Association for the Advancement of Science
• Subject: Air pollution / Air quality / Analysis methods / Applied sciences / Artificial satellites / Atmospheric chemistry / Atmospheric pollution / climate / Climate change / Developing countries / Emission / Emission inventories / Emission measurements / Emissions / Exact sciences and technology / Inventories / latitude / LDCs / Megacities / Nitric oxide / Nitrogen dioxide / Nitrogen oxides / Organic Chemistry / Photochemicals / Photochemistry / Pixels / Plumes / Point sources / Pollutant emissions / Pollutants / Pollutants physicochemistry study: properties, effects, reactions, transport and distribution / Pollution / Public health / Riyadh / Satellite observation / Satellites / Stockpiling / Troposphere / Urban areas / Wind / Wind direction / Wind velocity / winter