Nonmetal PollutantsFluorides and as

Nonmetal Pollutants
Fluorides and asbestos are nonmetal pollutants. Fluorine is a by-product of coal combustion. It is released, entirely in the gas phase, in relatively large quantities. Being a reactive element, it combines readily with other atoms and molecules to form fluorides, which are respiratory irritants. They are also phytotoxins (4), and their main environmental impact is on plants. Fluorides cause leaf damage and eventual defoliation. Airborne asbestos originates from industrial use and from the demolition of old buildings containing asbestos. Its health effects are mostly limited to asbestos workers and to workers who are incidentally exposed to asbestos while performing their duties. Therefore, exposure to asbestos is considered an occupational hazard. The health effects of this exposure are discussed in Chapter 8.
Trends and Present Status of Air Quality
Table 9.2 lists the U.S. National Ambient Air Quality Standards (NAAQS) and the World Health Organization (WHO) guidelines for the major urban air pollutants. Data in Figure 9.3 show the trends in sulfur dioxide in the air of selected cities in the United States and around the world from 1976–78 through 1990–95. The data indicate that in general, between 1976 and 1995 good progress toward abatement of sulfur dioxide pollution was achieved in industrialized countries. It is important to note that the data presented in Figure 9.3 are the mean values of the residential, commercial, industrial, and suburban areas. Certain areas of a city evaluated by them- selves may have exceed the standards. For instance, in the residential area in the city center of New York, the mean daily concentrations of SO2 were, for three monitoring periods, above the WHO guidelines (72 mg/m3 in 1976–78, 74 mg/m3 in 1979–81, and 65 mg/m3 in 1982–85) (2). Among the cities of the industrialized world, Milan stood out as exceptionally polluted with SO2 during the period 1976–78, highly exceeding WHO guidelines, but by 1990–95 the levels of sulfur dioxide decreased well below WHO guidelines. No progress in abatement of sulfur dioxide pollution has been achieved in cities of the developing nations. In some of them, as for example Teheran, Calcutta, and Beijing, pollution increased considerably during the monitor- ing period. This was probably a result of an attempt at industrialization with insufficient investment in modern technology. Data in Figure 9.4 show the trends in mean daily concentrations of SPM in selected cities throughout the world. In North America and, except for Brussels, in Europe progress in pollution abatement has been achieved and in most cases the concentrations of suspended particulate matter was within WHO guidlines. On the other hand, in all cities of the developing world

Kết quả (Việt) 1:

Các chất ô nhiễm phi kimFlorua và amiăng là phi kim chất ô nhiễm. Flo là một sản phẩm phụ của sự cháy than. Nó được phát hành, hoàn toàn trong giai đoạn khí, với số lượng tương đối lớn. Nó là một yếu tố phản ứng, kết hợp dễ dàng với các nguyên tử và phân tử để hình thức fluorides, đó là chất kích thích đường hô hấp. Họ cũng khá (4), và tác động môi trường của họ chính là trên cây. Florua gây ra thiệt hại lá và cuối cùng phương. Airborne amiăng bắt nguồn từ việc sử dụng công nghiệp và từ phá hủy các tòa nhà cũ có chứa amiăng. Các hiệu ứng y tế được chủ yếu là giới hạn người lao động amiăng và công nhân đã được ngẫu nhiên tiếp xúc với amiăng trong khi thực hiện nhiệm vụ của họ. Do đó, tiếp xúc với amiăng được coi là một mối nguy hiểm nghề nghiệp. Những ảnh hưởng sức khỏe tiếp xúc này sẽ được thảo luận trong chương 8.Xu hướng và các tình trạng hiện nay của chất lượng không khíTable 9.2 lists the U.S. National Ambient Air Quality Standards (NAAQS) and the World Health Organization (WHO) guidelines for the major urban air pollutants. Data in Figure 9.3 show the trends in sulfur dioxide in the air of selected cities in the United States and around the world from 1976–78 through 1990–95. The data indicate that in general, between 1976 and 1995 good progress toward abatement of sulfur dioxide pollution was achieved in industrialized countries. It is important to note that the data presented in Figure 9.3 are the mean values of the residential, commercial, industrial, and suburban areas. Certain areas of a city evaluated by them- selves may have exceed the standards. For instance, in the residential area in the city center of New York, the mean daily concentrations of SO2 were, for three monitoring periods, above the WHO guidelines (72 mg/m3 in 1976–78, 74 mg/m3 in 1979–81, and 65 mg/m3 in 1982–85) (2). Among the cities of the industrialized world, Milan stood out as exceptionally polluted with SO2 during the period 1976–78, highly exceeding WHO guidelines, but by 1990–95 the levels of sulfur dioxide decreased well below WHO guidelines. No progress in abatement of sulfur dioxide pollution has been achieved in cities of the developing nations. In some of them, as for example Teheran, Calcutta, and Beijing, pollution increased considerably during the monitor- ing period. This was probably a result of an attempt at industrialization with insufficient investment in modern technology. Data in Figure 9.4 show the trends in mean daily concentrations of SPM in selected cities throughout the world. In North America and, except for Brussels, in Europe progress in pollution abatement has been achieved and in most cases the concentrations of suspended particulate matter was within WHO guidlines. On the other hand, in all cities of the developing world