Mortality in polluted cities exceed that of cleaner cities by 15 to 20 percent.
Mortality in polluted cities exceed that of cleaner cities by 15 to 20 percent.

With the dawn of the industrial revolution, a global economy has emerged, and our population has grown exponentially. Understanding our external physical, biological and chemical environment, and how it affects individuals and man-made systems, has become an essential part of maintaining a healthy human population.

Air Pollution

The World Health Organization estimates that urban outdoor air pollution causes 1.3 million annual deaths worldwide and indoor air pollution, typically from burning biomass and coal, contributes to an additional 2 million global deaths per year. Air quality is threatened by pollutants like particulate matter, carbon monoxide, ozone, nitrogen dioxide and sulfur dioxide, which affect exposed populations with sometimes fatal respiratory and circulatory health problems.

Water Eutrophication

While the need for clean water grows with the population, our fresh water sources are more threatened today than ever before. The most prevalent global water quality issue today is eutrophication, due to high concentrations of nutrients, particularly phosphates and nitrates from agriculture, resulting in excessive algae growth. Eutrophication renders some sources unsafe for consumption, interferes with water treatment processes, encourages toxin-producing bacteria, and reduces the water's aesthetic appeal. Large ocean dead zones near the moughts of rivers can destroy the economies of coastal communities and contaminate drinking and recreational waters. While water shortages are already affecting communities across the globe, wastewater effluent and food-growing needs are expected to exacerbate global eutrophication by adding a projected 10 to 15 percent increase in nitrogen loads in river and coastal ecosystems over the next three decades.

Hazardous Waste

Waste from radioactive materials, pesticides, herbicides, fungicides and nematocides all have the potential to degrade the environment and affect the population on a local and global scale. This waste enters the environment through legal and illegal dumping and improper or faulty storage methods, contaminating the soil and water. Around 1978, residents of Love Canal, New York, developed illnesses after their water was polluted through improper storage of industrial waste including carcinogens like benzene. After a heavy rain, the waste leached from the disposal drums buried beneath the community, leaving burns on children after playing outside, increasing local birth defects, and raising white-blood-cell levels, a precursor sign of leukemia, in many residents.

Climate Change

The human population has grown and adapted within a relatively static global climate since the last ice age, completely shaping our modern society. However, the Earth's average temperature has increased by .78 degrees Celsius (1.4 degrees Fahrenheit) over the past century and the Earth appears to be entering an era of global climate change. The National Aeronautics and Space Administration projects that communities will be affected by raising global temperatures in both positive and negative ways, but the overall cost of climate change is expected to be significant and to increase over time. Affects of climate change that have impacted our population already include an increase in the frequency and intensity of tropical storms, an increase in wild fires, and longer and more frequent heat waves and droughts. This could lead to food and water shortages, destruction of livelihoods, and the disruption and release of hazardous waste.