Indoor air pollution. Public health problem
Indoor air pollution consists of toxic gases or particles that can harm human health. We spend most of our time indoors surrounded by sources of air pollution: consumer products, gas appliances, building materials, cigarettes, and furniture can all contribute to the problem. U.S. EPA, 1987 ranked indoor air pollution 4th in cancer risk among the 13 top environmental problems analyzed. Indoor radon ranked first.
Factors contributing to the high risk:
1) People are spending most of their time indoors (an average of 87% of their 24-hour day indoors).
2) Indoor air pollutant levels are often higher than those outdoors (formaldehyde, chloroform, and styrene, range from 2 to 50 times higher).
3) Exposure to pollutants such as environmental tobacco smoke and radon occurs almost entirely indoors.
The amount of air pollution that we breathe is primarily determined by the indoor air! According to The world health report 2002 indoor air pollution is responsible for 2.7% of the global burden of disease.
More than three billion people worldwide continue to depend on solid fuels, including biomass fuels (wood, dung, agricultural residues) and coal, for their energy needs.
Cooking and heating with solid fuels on open fires or traditional stoves results in high levels of indoor air pollution. Indoor smoke contains a range of health-damaging pollutants, such as small particles and carbon monoxide, and particulate pollution levels may be 20 times higher than accepted guideline values.
Yet, the toxic emissions from many of these sources are not controlled or are only partially controlled by state or local laws.
Primary air pollutants: 5 types of materials released directly into the atmosphere in a harmful form: Carbon monoxide (CO), Particulate matter (PM), Sulfur dioxide (SO2), Nitrogen oxides (NOx) and Volatile organic compounds (hydrocarbons).
Concentration of air pollutants may be expressed in: mg/m3, ppm = parts per million, or 10-6 ppb = parts per billion, or 10-9
M
aximum
Admissible Concentration
(MAC)
of
pollutant is standard
level of air pollutant below which there is virtually no harm to
human health or environment. These standards are set to protect
public health.
Biomagnification – the process whereby the concentration of a fat-soluble contaminant increases as it passes up the food chain. With which consumption step, the concentration of the contaminant in the consumer biomass is magnified (from 10 ppm to 106 ppm).
Magnification ratio (MR) – ratio of a real air pollutant concentration to maximum admissible concentration (MAC). It shows how many times real concentration of pollutant in the air exceeds standard level.
Example: Magnification ratio of CO equals 2:
MR(CO)
=
=
2
Toxic substances (pesticides, herbicides, mercury, lead etc) are able to accumulate in the cells and tissues of any organism. In marine systems concentration of toxins in organisms is increasing as we move up the food chain from producers to consumers:
water (sea, lake) phytoplankton zooplankton fish fish-eating birds.
Bioaccumulation Factor (BAF) is the ratio of a toxic substance’s concentration in a given organism to that in the surrounding medium (water).
Biomagnification Factor (BMF) is the ratio of concentration of toxic substance in a higher level of the food chain to that in the lower level of the same food chain.