Sulfuric acid health effects

Copper and Copper-Containing Alloys. Either sulfuric or hydrochloric acid may be used effectively to remove the oxide film on copper (qv) or copper-containing alloys. Mixtures of chromic and sulfuric acids not only remove oxides, but also brighten the metal surface. However, health and safety issues related to chromium(VT) make chromic acid less than desirable. 

Health effects attributed to sulfur oxides are likely due to exposure to sulfur dioxide, sulfate aerosols, and sulfur dioxide adsorbed onto particulate matter. Alone, sulfur dioxide will dissolve in the watery fluids of the upper respiratory system and be absorbed into the bloodstream. Sulfur dioxide reacts with other substances in the atmosphere to form sulfate aerosols. Since most sulfate aerosols are part of PMj 5, they may have an important role in the health impacts associated with fine particulates. However, sulfate aerosols can be transported long distances through the atmosphere before deposition actually occurs. Average sulfate aerosol concentrations are about 40% of average fine particulate levels in regions where fuels with high sulfur content are commonly used. Sulfur dioxide adsorbed on particles can be carried deep into the pulmonary system. Therefore, reducing concentrations of particulate matter may also reduce the health impacts of sulfur dioxide. Acid aerosols affect respiratory and sensory functions. 

US EPA Health Effects Assessment for Sulfuric Acid. Report No EPA/540/1-86/031, p 33. Washington, DC, US Environmental Protection Agency, Environmental Criteria and Assessment Office, 1984... 

Sulfur dioxide. The sources are burning coal and oil, especially high sulfur coal from Eastern US, and industrial processes (paper and metal industry). Health effects include breathing problems, which may cause permanent damage to lungs. Environmental effects are as follows S02 is an ingredient of acid rain (acid aerosols), which can damage trees and life in lakes. Acid aerosols can also reduce visibility. 

Thus, atmospheric research in the eastern U. S. has been dominated by the need for a better understanding of sulfur species, first because of presumed human health effects of S02, then because of human health effects of sulfates, and now because of effects of sulfate and acid upon plant and animal life (and, to a lesser extent, on building materials, statues, etc.) in the East, and because of visibility degradation in the West. 

J.Q., K. Dumler, V. Rebolledo, P.V. Williams, and W.E. Pierson. 1993. Respiratory effects of inhaled sulfuric acid on senior asthmatics and nonasthmatics. Arch. Environ. Health 48 (3) 171-175. 

More recent attention has focused on the abundance of very fine (submicron) and very acidic (pH l) aerosol emitted from volcanoes (Allen et al., 2002 Mather et al., 2003b). The few reports available of the human health effects of fine sulfuric acid aerosol are confined to industrial incidents, e.g., the case of a community exposed to emissions from a titanium dioxide plant in Japan in the 1960s, in which some 600 individuals living within 5 km of the plant reported asthmatic symptoms (Kitagawa, 1984). 

The respiratory health effects of vog and volcanic gases such as sulfur dioxide are tied to the generation of locally acidic environments in the lung and respiratory tract fluids by condensation of SO2 and other acid gases, uptake of acid-sulfate aerosol droplets, and the dissolution of acid-bearing, sulfate- or chloride-rich salts from the vog particulates by the fluids lining the respiratory tract. 

Donora in Pennsylvania, and London. Excess mortality accompanied each of these pollution episodes and has been attributed to the smoke and sulfur dioxide generated by fossil fuel combustion. A number of recent epidemiologic, clinical, and animal studies have confirmed that both particulate matter and sulfur oxides produce adverse health effects. These adverse effects have been observed during pollution episodes in which the gas and particle concentrations do not approach the magnitude of the three incidences mentioned previously. Delineating the relative contribution of particulate matter and sulfur oxides to these adverse effects is difficult because of the chemicophysical association of sulfur oxides and particles. This section is limited to the current state of knowledge on sulfur oxides and acid aerosol-related health effects. The following section will discuss particulate matter-related effects. 

Despite the clear evidence of a subpopulation of individuals sensitive to near-ambient peak levels of sulfur dioxide, the two-decade-old NAAQS for sulfur dioxide has not been changed nor has a short-term peak standard been instituted. A considerably greater amount of attention has been placed on the contribution of airborne particulates, particularly those associated with sulfur oxides, to adverse health effects. The carbon-, mineral-, and heavy metal-based particles produced during fossil fuel combustion and smelting promote the conversion of sulfur dioxide to sulfuric acid. Recognition of sulfur dioxide-particle interactions comes as a result of findings garnered from a number of animal studies and the characterization of sulfuric acid, ammonium sulfate, and ammonium bisulfate associated with atmospheric particles. The importance of the coexistence of sulfur oxides and particulate matter is reflected in the... 

Although pure sulfuric acid droplets are used almost exclusively in controlled exposures, ambient acid aerosols are chemically complex and are proposed to be composed of a core consisting of carbon, minerals, or heavy metals surrounded by acidic (sulfuric or nitric acid) surface material. Thus, knowing which chemical species is responsible for acid aerosol-induced adverse health effects is fundamental in developing proper control strategies for reducing air pollutants at their source. 

Amdur MO (1989) Health effects of air pollutants Sulfuric acid, the old and the new. Environmental Health Perspectives 81 109-113 (discussion 121-122). 

EPA. 1979. Effects of endogenous ammonia on neutralization of inhaled sulfuric acid aerosols. Cininnatti, OH U S. Enviromnental Protection Agency, Health Effects Research Lab. EPA-600/1-79-045PB 80 147 978. 

A second concern was that under some conditions sulfur dioxide in exhaust could be emitted as sulfuric acid as a result of catalytic oxidation over the noble metal catalyst. To answer this concern General Motors conducted a 350-car test designed to simulate sulfate emissions on a busy expressway. The U.S. Environmental Protection Agency, other vehicle manufacturers, and several independent environmental monitoring organizations participated in the experiment. This experiment showed conclusively that ambient levels of sulfuric acid under this worse-case simulated exposure situation were far below threshold levels known to produce adverse health effects. 

In addition to its health effects on humans, sulfur dioxide has some important consequences for the physical and biological environment. Those effects occur because sulfur dioxide released to the atmosphere from electricity-generating plants and factories combines with moisture in the air to form sulfuric acid. Sulfuric acid then falls to earth in the form of acid rain, acid snow, or some other form of acid precipitation where it damages buildings and other structures, trees and other plant life, and fish and other aquatic organisms. Since 1995, the EPA has sponsored a variety of control programs designed to reduce the release of sulfur dioxide into the atmosphere to prevent such problems. 

---