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Air pollutants: Lead

What is lead pollution?

Lead (Pb) is a naturally occurring heavy metal that is found in the Earth’s crust. It is denser than most common materials, soft, malleable and has a low melting point. This capability to change easily the state from solid to liquid at atmospheric pressure is favouring its facility of being introduced as an air pollutant into the atmosphere.

How does lead get into the air?

Major sources of lead in the air are mining, metal manufacturing and piston-engine aircraft operating on leaded aviation fuel. Other sources of lead air pollution are industrial productions, waste incineration, recycling, mobilization of previously buried lead, utilities and lead-acid battery manufacturers.

Peak of lead emissions to the atmosphere had place during Industrial Revolution and with the usage of leaded gasoline during the last decades of the 20th century. Nowadays, high lead emissions still have place, especially in developing countries where industrial emissions arising from coal burning prevail.

What are the environmental and health effects of lead pollution?

Lead has not as much influence on the environment as other pollutants, but it can have a noticeable impact on plants. Lead accumulate on soils for a long time (hundreds or even thousands of years) and also can combine with other metals to inhibit photosynthesis. At high lead pollution levels, plants growth and survival may suffer adverse effects and can cause neurological problems to vertebrates.

Lead air pollution health effects on humans usually are neurological effects in children and cardiovascular effects (high blood pressure and heart disease, for example) in adults.

Lead exposure on humans can be very harmful, involving almost every organ and system in the human body. Once it is inhaled, lead is placed on the bloodstream and bones driving to a possible case of lead poisoning.  

Lead poisoning: symptoms and treatment

Apart from air pollution, lead poisoning come from different sources, such as water, dust, food or consumer products. The effects it may cause to each individual depends on the levels and the time exposure to the pollutant.

Some lead poisoning symptoms or signs that could indicate you are in danger are: headache, intermittent abdominal pain, loss of appetite, nausea, diarrhea, constipation, memory loss, kidney failure, male reproductive problems, depression, weakness, pain or tingling in the extremities and muscles.

In children, lead poisoning is prone to cause similar symptoms: loss of appetite, abdominal pain, vomiting, weight loss, constipation, anemia, kidney failure, irritability, lethargy, learning disabilities and behavioral problems. Others such as slow development of normal childhood behaviors (like the usage of words and talking) and permanent neurological problems (like learning deficits and lowered IQ) are also commonly diagnosticated to this segment. During the pregnancy, breathing lead polluted air may increase the risk of premature birth or low birth weight.

According to the level of poisoning and what part of your organism is affected, treatments may change. We will have a look to lead poisoning treatments due to air pollution.

When lead levels are high on blood, lead intoxication can be treated with chelation therapy or treatment of iron, calcium and zinc deficiencies, as these are treatments related to lead absorption.

How is lead air pollution controlled?

Over the years, developed countries have reached some agreements to control pollution. Each country or state has its own implementation plan. For example, the Clean Air Act made by the U.S. Environmental Protection Agency (EPA) establishes National Ambient Air Quality Standards (NAAQS) for those criteria pollutants considered most harmful for health and the environment. Another example is the European Union Air Quality Directive by the European Environmental Agency, which also establishes some standards and tips to reduce air pollution, both indoors and outdoors.

Lead is considered both a primary and a secondary criteria pollutant due to its effects either on public health and the environment. Maximum permitted or recommended levels of lead in the air are:

  • Nothing is included in the World Health Organization (WHO) guidelines.
  • NAAQS: cannot exceed 0,15 μg/m³ for 3 months average.
  • EU Air Quality Directive: cannot exceed 0,5 μg/m³ over a year.
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