Có hơn 1 triệu trang trại chăn nuôi gia súc, gia cầm ở Hoa Kỳ. Khoảng một phần ba các trang trại nuôi động vật trong khu vực kín, đủ điều kiện chúng là hoạt động thức ăn chăn nuôi (AFOs) (USDA, 1999). Chất gây ô nhiễm không khí (không khí phát thải) và mùi đã luôn luôn được liên kết với chăn nuôi và gia cầm sản xuất. Với xu hướng các trang web sản xuất lớn hơn và tập trung hơn, tuy nhiên, khí, bụi và mùi hôi nhanh chóng trở thành vấn đề quan trọng cho các nhà sản xuất động vật | 7 Animal Waste and Air Quality Problems are next to the hog farm and to tell you the truth I don t know what in the world we are goin a do. It s not so bad now but when the wind changes and they turn on the fans it is very bad. My husband suffers from it a good deal. In the house we have nine special air conditions and six air purifiers runnin all the time so it s not too awful but outside when the wind is right your eyes just flame up and your throat hurts. That s why I only ask fifty dollars a month for the apartment. Otherwise it would be two hundred. So if you can stand the hog farm it s a good deal. Do you have a tendency to asthma Proulx 2002 p. 309 Some years ago our family took a trip across the Midwest to visit relatives in Iowa and for thousands of miles along the way we saw virtually no animal life except feedlots full of cattle surely the most unappetizing sight and smell I ve encountered in my life and my life includes some years of intimacy with diaper pails . And we saw almost no plant life but the endless fields of corn and soybeans required to feed those pathetic penned beasts. Our kids kept asking mile after mile What used to be here Kingsolver 2002 p. 119-120 INTRODUCTION There are more than 1 million livestock and poultry farms in the United States. About one-third of these farms raise animals in confined areas qualifying them as animal feed operations AFOs USDA 1999 . Airborne contaminants air emissions and odor have always been associated with livestock and poultry production. With the trend toward larger and more-concentrated production sites however gases dust and odors are rapidly becoming important issues for animal producers. Even though very little evidence is available on the impact of airborne contaminants and odor from livestock operations on human health the increasing intolerance of odors and the economic importance of animal agriculture have resulted in an urgent need for all stakeholders to find adequate solutions .
