Measurements and processing of air pollutants in the agrifood industry

The agrifood industry is one of France's most important activities in terms of both volume and sales. In 2006, France's agrifood industry produced 129,910 billion euros (INSEE data). That same year, the foreign trade surplus in this sector reached 8.6 billion euros. These industries produce a wide variety of foodstuffs (meat, milk, beverages, preserves, breads and pastries, sugar, etc.), ranging from practically unprocessed products to highly elaborate ready-made meals.

Like all human activities, the agri-food industry generates liquid and gaseous waste and effluents, pollutants which must be minimized before they are released into the environment. Among these, gaseous emissions laden with solid or liquid aerosols, volatile organic compounds and/or odorous molecules produce nuisances that are generally poorly appreciated by neighbors. Depending on specific activities and production levels, flow rates vary widely, from a few thousand to several tens of thousands of m³ · h^–1[1][33][44]. Gaseous flows are laden with organic molecules such as mercaptans, sulfides, amines, volatile fatty acids, ketones, aldehydes, alcohols... and inorganic compounds such as ammonia or hydrogen sulfide. Concentrations are relatively low: between a few μg · m^–3 and a few mg · m^–3. In terms of flow and quality, these emissions are often comparable to those causing olfactory nuisance. This polluted air needs to be treated before being released into the atmosphere, in order to reduce its impact on human health and its effects on the environment.

This article will therefore focus on the sources, measurement of constituents and treatment of gaseous emissions from food processing activities. The emissions studied do not concern those linked to the packaging of finished products, but those due more specifically to the raw materials, finished products or by-products generated.