Urban Emissions Measured with Aircraft

Abstract

Detailed knowledge of the quantity and composition of urban emissions is a prerequisite for successful application of atmospheric models to predict transport and distribution of primary and secondary air pollutants in the troposphere. We investigate the prospects and limitations of aircraft measurements in the determination of emission fluxes from urban areas. Our analysis focuses on data collected in September 1994 in and around Athens, Greece. Generally, emission fluxes from cities can be quantified with aircraft and with the minimum acceptable precision (uncertainty better than a factor of 2) only under very favorable meteorological conditions, namely in a homogeneous flow field in a well-mixed boundary layer. Better accuracy can be achieved only through ensemble averaging of repeated measurements. From our measurements in the Athens area, we deduced relative emission ratios of pollutant gases. With the support of ground-based measurements in a street canyon, the emission ratios NO x /CO, SO 2 /CO, and volatile organic compounds/CO (34 individual VOCs) could be determined with high precision. These results are very useful in analyzing differences between various existing emission inventories. Our data for VOCs reveal that the non-traffic emissions are of the same magnitude as the emissions originating from traffic.

Differences between measured and reported volatile organic compound emissions from oil sands facilities in Alberta, Canada

“…The methodology uses a combination of box-like aircraft flight patterns enclosing each of the main surface mining facilities, comprehensive measurement methods at high time resolution, and the development and application of a computational top-down emission rate retrieval algorithm (TERRA) (25) for deriving facility emission rates from measurements of chemical concentration and meteorology. In contrast to previous aircraft VOC emission studies (26)(27)(28)(29), horizontal and vertical advection and diffusion, chemical reactions, and air mass density changes, all based on measurements, were included in the computation of mass balance of the VOCs from the aircraft measurements, thus reducing the uncertainties in the derived emission rates (25). Another advantage of this methodology is its ability to provide the emission rates of tracers used for the determination of emission rates for many VOCs from discrete measurements, such as canister sampling.…”

Characterization of urban pollutant emission fluxes and ambient concentration distributions using a mobile laboratory with rapid response instrumentation

“…7 More recently, this class of airborne mobile laboratories has been deployed to study the evolution of urban and industrial pollution plumes. [8][9][10][11] However, as important and informative as the 3D data on urban and industrial pollution clouds obtained by these highly instrumented research aircraft can be, the expense of their deployment severely limits their use, even in the developed world's urban regions. In addition, they are of limited utility in characterizing all but the largest emission sources since their airspeed makes resolving finer scale plumes difficult and aircraft operation in the atmospheric boundary layer directly over many urban areas is restricted by air traffic control and other safety and security regulations.…”

Predicting photochemical pollution in an industrial area

“…The same report mentioned that the Thriassion Plain hosts 25% of the large industries of Attica and a corresponding 52.3% of the total diesel consumption of this prefecture, while 46 industries out of the 1,044 operating in the area were reported as polluting through their production processes (Ministry of Environment 1989; Klemm and Ziomas 1998). Recent data from GERPPE (2006) reports at least 2200 large and small industrial establishments.…”