Introduction to Climate Change

2. Air Pollutants and Impacts

Particulates are emitted from most industrial sources and may take many forms. The most obvious effect of relatively high concentrations of particulate matter is reduced atmospheric visibility. More significantly, particulates exacerbate respiratory illnesses and over the long term increase chronic bronchitis. According to the World Bank, reducing the levels of particulate emissions to meet World Health Organization standards would save 300,000 to 700,000 lives a year. Particulates can also cause direct chemical damage, such as corroding metallic surfaces and damaging vegetation.

Nitrous oxides (NOx) are emitted from many industrial sources as well as automobiles. NOx is also a precursor to photochemical smog, impairing respiratory function in asthmatics, increasing incidences of acute respiratory illness, and causing throat and eye irritation. NOx, when mixed with water, causes acid rain. Acid rain has damaged rivers, lakes and forests in both eastern North America and Europe. NOx is the subject of a protocol to the LRTAP Convention as well as the U.S. Canada Bilateral Air Quality Agreement (BAQA).

Sulfur dioxide (SO2) is also a primary cause of acid rain. The major sources of SO2 are coal and oil combustion, i.e., stationary utility power plants, industrial boilers, and residential heaters. The effects of acid rain on the environment include acidification of natural water sources leading to adversely affected fish populations and the leaching of nutrients in the soil leading to loss in productivity of crops and forests and changes in the natural vegetation. SO2 can cause respiratory tract problems, exacerbate respiratory illnesses, and over the long term increase permanent harm to lung tissue and chronic bronchitis. Both the LRTAP regime and the U.S. Canada BAQA address SO2.

Volatile organic compounds (VOCs) are emitted from many industrial sources as well as automobile emissions. In the presence of sunlight, VOCs contribute to the creation of ozone and "smog" at the ground level. Such smog exacerbates asthma, causes eye and nose irritation, chest discomfort, headaches and nausea, worsens coughs, impairs pulmonary functions in people who are exercising, reduces the resistance to lung disease, and causes scarring of lungs over the long term. VOCs are covered by a protocol to the LRTAP Convention and are also the subject of international efforts to clean up urban air pollution in developing countries.

Persistent organic pollutants (POPs). Many industrial processes emit chemical byproducts in the form of organochlorides. These chemicals, which do not decompose easily and can travel great distances, bioaccumulate in plant and animal matter, resulting in abnormally high concentrations in animals at the top of the food chain. While the effects of POPs on animals and human health have been debated, many have linked the increase in the level of POPs to cancers, immune deficiencies, and decreases in fertility and reproductive stress. POPs are the subject of a protocol under the LRTAP Convention and the 2001 Stockholm POPs Convention.

Carbon Dioxide (CO2) is the largest contributor to anthropogenic climate change and global warming. The economic, social, environmental and health impacts of climate change and global warming are hotly debated but are generally viewed to be substantial. CO2 is emitted from the combustion of all fossil fuels. CO2 emissions are now addressed under the 1992 Framework Convention on Climate Change and the 1997 Kyoto Protocol .

Chloroflourocarbons (CFCs) and a number of related chemicals lead to the depletion of the ozone layer, which in turn leads to increased levels of ultraviolet radiation striking the earth's surface. Such increased levels of ultraviolet radiation are expected to cause an estimated 300,000 additional cases of skin cancer and 1.7 million cases of cataracts worldwide, as well as significant harm to fish, wildlife and agricultural production. CFCs are covered by both the Montreal Protocol and climate change regimes.