Sulfur is present in the atmosphere as a constituent of more than 15 compounds and in valence states ranging from −2 to +6. Nearly all of the compounds have both natural and anthropogenic sources. This paper reviews the present information on the reactions of these compounds and their products with typical atmospheric species. It is shown that atmospheric sulfur chemistry proceeds monotonically in the direction of increasing sulfur oxidation and that the gas phase transformation of reduced sulfur compounds to sulfate aerosol in all ambient atmospheres can be described by a common chain consisting of five chemical steps followed by a heterogeneous loss process.

The homogeneous chemistry of atmospheric sulfur

Formic acid is a ubiquitous constituent of the atmospheric gas and of precipitation, but itssources and their fluxes are poorly understood. One source not previously examined, emissionsfrom formicine ants, IS assessed in this work, and it is shown that, except in urban areas andparticularly in tropical areas, these ants may be a significant source of the formic acid found insome parts of the continental troposphere. This process could thus provide a new example of apotentially strong interaction linking the biosphere and the atmosphere. DOI: 10.1111/j.1600-0889.1988.tb00107.x

Atmospheric formic acid from formicine ants: a preliminary assessment

The literature on rigid polyurethane foam was reviewed with an emphasis on the gaseous products generated under various thermal-decomposition conditions and the toxicity of those products. The review is limited to publications in English through 1984. Carbon monoxide (CO) and hydrogen cyanide (HCN) were the predominant toxicants found among more than 100 other gaseous products. The generation of CO and HCN was found to increase with increasing combustion temperatures. Many test methods were used to assess the acute inhalation toxicity of combustion products from various rigid polyurethane foams. Lethality, incapacitation, physiological, and biochemical parameters were employed as biological and points. In general, the combustion products generated from rigid polyurethane foam in the flaming mode appear to be more toxic than those produced in the non-flaming mode. The LC50 values for 30 minute exposures ranged from 10 to 17 mg/l in the flaming mode and were greater than 34 mg/l in the nonflaming mode. With the exception of one case in which a reactive type phosphorus containng fire retardant was used, the addition of fire retardants to rigid polyurethane foams does not appear to generate unusual toxic combustion products.

A review of the literature on the gaseous products and toxicity generated from the pyrolysis and combustion of rigid polyurethane foams

Spatiotemporal variations of monocarboxylic acids in snow layers along a transect from Zhongshan Station to Dome A, eastern Antarctica

Formate and acetate are ubiquitous in the troposphere. Their occurrence is closely related to processes in the biosphere and contributes to an understanding of carbon biogeochemical cycles. A 43-year record of formate and acetate in an ice core from Glacier 1 (43°06′N, 86°49′E) at Urumqi river head, Tianshan, west China was investigated. Fluctuating between 22.7 ng · g− and 2830.7 ng · g−, acetate concentration averages 373.2 ± 376.1 ng · g−1 (mean ± lσ, N = 541) and is the highest anion in the record. Next to acetate, the concentration for formate varies between 2.1 ng · g−1 and 795.5 ng · g−1 and averages 61.1 ± 89.0 ng · g−1 (N = 541). The formate to acetate ratio averages 0.22 ± 0.25 (N = 541), indicating that the chief source is from fossil fuel combustion, coal burning in particular. The two species co-varied in the past four decades and exhibited periods of high concentration from the early 1960s to the middle of 1970s and from the early 1980s to the middle of 1990s, separated by a time of the lower concentration between 1975–1980. These variations may reflect the local/regional anthropogenic pollution to the atmosphere as well as the economic development of north-western China.

Formate and acetate as recorded in a mid-latitude glacier in west China

: The Bureau of Mines through contract with Ultrasystems, Inc., obtained gram per gram data of products formed on thermal oxidative degradation of selected compositions, both under dynamic and static conditions. Four broad classes of materials were studied: Polyvinyl chloride compositions, neoprene compositions, rigid urethane foams, and variously treated woods. Whenever possible, comparisons between pure components and composites were attempted. Thermogravimetric and differential thermal analyses were performed to gain understanding of the processes occurring and to explore the feasibility of using these analyses as a method of material identification. The toxic products detected and quantitated included HCl, H2S CO, SO2, CS2, COS, HCOOH, CH3COOH, formaldehyde, acrolein, C6H6 , chloroprene, chloroethanol, benzyl chloride, aniline, and furfural.

Arthur M. Hartstein

Papers

Coal Mine Combustion Products: Neoprenes, Polyvinyl Chloride Compositions, Urethane Foam, and Wood