Environmental Risk

Pollution and Environmental Risk in Cities

Industrial, domestic, and transportation activities in cities generate waste and by-products that lower air and water quality, with resulting public health impacts. Air pollution in many cities around the world poses near- and long-term hazards to public health. In the United States, for example, high concentration of fine particulate matter—emitted as a result of industrial processes, transportation, and home heating—has been linked to asthma episodes, increases in emergency room visits for respiratory problems, pulmonary disease and asthma. There are over 1,000 chemical compounds and elements that have been identified by the Environmental Protection Agency as potential hazardous air pollutants. These pollutants are released into the air by a variety of sources and can have lasting long-term health effects, potentially including some forms of cancer.

Indoor environments also expose occupants to potentially hazardous chemicals as a result of building materials, by-products from cleaning equipment, emissions from cooling [Page 182]or heating, or presence of dust and particulate matter. This issue has only recently received attention, and it will pose an additional challenge to city planners striving to design safe buildings for places of both business and residence.

Water quality and availability can be affected by urban activities in part related to the generation of heat and organic waste. In fact, cities play a significant role in nutrient cycling locally, and potentially globally. Waste nitrogen is a particularly harmful nutrient that can cause eutrophication and can support toxic algal blooms. In cities, this can reduce surface water quality, taint potable supplies, limit recreational opportunities, and reduce biodiversity. Developed cities often have denitrification technology to reduce leachate of nitrogen from industrial runoff and waste disposal, but continued population growth and development of industry could limit the capacity of existing infrastructure to handle increasing volumes of waste in the future.

Physical Risk Factors and Climate Change

Physical climate change impacts have multifaceted direct and indirect implications for urban settlements. These impacts often affect multiple sectors of human activities (e.g., public health, the economy) and can accentuate vulnerabilities associated with, for example, overcrowding or development in hazardous areas. Floods, severe storms, landslides, and earthquakes claim lives and can cause lasting damage to the livelihoods of urban residents by destroying assets and causing physical impairments that require time away from work. In this way, environmental risk factors can make it difficult to address issues of poverty in cities, because the poor are often most economically impaired by these factors.

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