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AIR POLLUTION – MONITORING MODELLING AND HEALTH

air pollution – monitoring, modelling and health - Ademloos

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184<br />

Air Pollution <strong>–</strong> Monitoring, Modelling and Health<br />

described by Turnbull et al. (2009). It was shown that the addition of fossil fuel, 14 C-free CO 2<br />

had the greatest influence on the spatial distribution of Δ 14 CO 2 . In addition, 14 CO 2 produced<br />

by nuclear reactors caused local enhancement in Δ 14 CO 2 in some samples.<br />

Δ 14 CO 2 increases by 5± 1.0% across the transect from 40 0 E to 120 0 E (Fig. 5) and this<br />

difference is significant at the 99% confidence level. The magnitude of the Δ 14 CO 2 gradient is<br />

consistent with the dispersion of fossil fuel CO 2 emissions produced in Europe and<br />

atmospheric transport across northern Asia dispersing and diluting the fossil fuel plume.<br />

The observed isotopic change implies a gradient of 1.8 ppm of fossil fuel derived CO 2<br />

(assuming a -2.8‰ change in Δ 14 CO 2 per ppm of fossil fuel CO 2 added). Δ 14 CO 2<br />

measurements from Niwot Ridge, Colorado, USA (NWR, 40.05° N, 105.58° W, 3475 m.a.s.l.)<br />

representing relatively clean free troposphere, give a mean Δ 14 CO 2 value of 66.8±1.3‰ for 3<br />

sampling dates during the time of the TROICA-8 campaign (grey bar in Fig. 5). The Eastern<br />

Siberian part of the TROICA transect shows values (62.8±0.5‰) most similar to the NWR<br />

value, consistent with an easterly dilution of the fossil fuel content in boundary layer air<br />

away from the primary source, but suggesting that some influence from the European fossil<br />

fuel CO 2 source remains in the Eastern Siberian air mass.<br />

Fig. 5. Δ 14 CO 2 as a function of longitude. Closed diamonds are the clean air Δ 14 CO 2<br />

dataset. Open symbols indicate samples that may be influenced by either nuclear reactor<br />

effluent (triangles) or local city pollution (circles). The shaded bar indicates the Niwot<br />

Ridge Δ 14 CO 2 value measured over the same time period and its 1-sigma error envelope.<br />

Modeled estimates for each sampling time and location have been done on the basis<br />

standard (solid line) and fast (dashed line) mixing (see Turnbull et al., 2009).<br />

3.6 Volatile organic compounds<br />

Volatile organic compounds (VOCs) were measured in a number of expeditions (Elansky et<br />

al., 2000; Elansky et al., 2001a). VOCs were retrieved analyzing sorbent samples or in air<br />

samples pumped into stainless-steel canisters. These measurements can be performed in<br />

mobile or stationary chemical laboratories.

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