Industrial emissions of trichloroethene, tetrachloroethene, and dichloromethane: Reactive Chlorine Emissions Inventory

Abstract

The identified emissions of the title compounds come predominantly from their use in industrial and commercial processes. Trichloroethene and tetrachloroethene have also been found as byproducts of gasoline and coal combustion; these sources were also considered but shown to be insignificant compared with industrial releases. Global emissions during 1990, amounting to 0.241±0.013 Tg of trichloroethene, 0.366±0.020 Tg of tetrachloroethene, and 0.583±0.032 Tg of dichloromethane (0.195±0.010, 0.313±0.017, and 0.487±0.027 Tg as chlorine, respectively) have been assigned to individual countries and thence to a 1° latitude × 1° longitude grid based on a combination of three data sets: regional sales data that were available on a continental scale; economic activity in the form of national Gross Domestic Products; and the population distribution within each country. For those countries where they were available, data for the quantities and locations of reported emissions were also incorporated. Uncertainty in the distributed emissions is ±4% relative to countries with the largest emissions. The results, which are complementary to the marine fluxes and releases from biomass burning reported by Khalil et al [this issue] and Lobert et al [this issue], respectively, are recorded here as maps and are also available from the Global Emissions Inventory Activity web site at http://groundhog.sprl.umich.edu/geia/rcei. While the industrial regions of North America, Europe, and Japan are the largest sites of anthropogenic emissions, there are also significant sources in the developing nations of Asia; in contrast, anthropogenic emissions within the southern hemisphere are much smaller and more widely dispersed. The total emissions of dichloromethane appear to match the observed atmospheric concentrations, but about 25% of the flux of tetrachloroethene calculated from observations remains unaccounted, and significant extra emissions of trichloroethene are necessary to effect a balance. The known sources have been examined thoroughly in this work, and so it is reasonably certain that the additional emissions are not a deliberate result of human activity; however, there is no means of discriminating their origin unequivocally, and the missing quantities may be inadvertent byproducts of anthropogenic activities.

Ambient air benzene at background sites in China's most developed coastal regions: Exposure levels, source implications and health risks

“…As toluene, ethylbenzene and xylenes are widely used in industrial solvents, much higher ratios of T/B, E/B and X/B are indicative of industrial emissions (Chan et al, 2006;Barletta et al, 2008). Furthermore, if we further divide samples into two groups by their T/B ratios, Group I with T/B b 2 and Group II with T/B N 2, we find closer correlations between benzene and tetrachloroethylene (C 2 Cl 4 ), a marker of industrial emissions (McCulloch et al, 1999;Zhang et al, 2012c), for Group II samples (r = 0.81, p b 0.001) than for Group I samples (r = 0.18, p N 0.05; Fig. 6a).…”

Spatio-temporal variations of sea surface halocarbon concentrations and fluxes from southern Yellow Sea

“…Volatile halogenated organic compounds (VHOC) include chlorocarbons such as chloroform (CHCl 3 ) and trichloroethylene (C 2 HCl 3 ), which are significant marine sources of chlorine to the atmosphere (McCulloch et al 1999;McCulloch 2003). VHOC also include bromocarbons such as bromodichloromethane (CHBrCl 2 ), chlorodibromomethane (CHBr 2 Cl), and bromoform (CHBr 3 ) that are important marine sources of biogenic reactive organic bromine (Chuck et al 2005).…”

Three-decade changes in chemical composition of precipitation in Guangzhou city, southern China: has precipitation recovered from acidification following sulphur dioxide emission control?

“…Elevated Cl ( concentration in precipitation was likely caused by increased hydrochloric acid (HCl) emissions in the study city due to the increased combustion of coal (Fig. 11, coal contains 0.01%Á0.2% Cl by weight in China, Jiang et al, 2001), and to a lesser extent, to increased waste incineration (McCulloch et al, 1999). Due to the high mobility of Cl ( , HCl can readily acidify both soils and surface water (Evans et al, 2011).…”