Tag: air pollution

Outdoor air pollution classified as carcinogenic by World Health Organization

air pollutionby Melissa Roper

It is not yet certain if climate change is the result of anthropogenic-sourced carbon emissions or, on the contrary, is a Sun-influenced phenomenon. As the debate on global warming versus global cooling continues, results of recent research draw attention towards an equally worrying side-effect of industry greenhouse gas emissions – the fatal implications of air pollution on human health. Earlier this month, 24 experts from 11 countries met at the International Agency for Cancer Research (IARC) headquarters in Lyon to assess the correlation between cancer and air pollution. IARC is the cancer specialized agency of the World Health Organization (WHO), the coordinating authority for health within the United Nations.

Cancer and air pollution: two widespread phenomena

The scientists evaluated over 1000 papers analysing the carcinogenicity of particulate matter and transport-related pollutants, and the results of the study will be published as Volume 109 of the IARC Monographs. According to the study’s Press release published on 17th October 2013, “outdoor air pollution [is] a leading environmental cause of cancer deaths”. This conclusion is the first paper to officially link the two:  both the worldwide rate of cancer and global air pollution have become alarmingly widespread phenomena in the past decades.  Cancer has become so common, that the international medical industry was revolutionized in order to address the problem in evermore effective ways. As Licensed Prescriptions explain, it has become possible to diagnose, prevent and treat cancer quickly, in some cases even without the need of a biopsy. One of the reasons why cancer has become such a frequent problem may be that “the air we breathe has become polluted with a mixture of cancer-causing substances” as summarized by Dr. Kurt Straif, Head of IARC Monographs.

Sources and effects of air pollution

The IARC study reports that although air pollution comes from a mixture of natural and anthropogenic sources, “the predominant sources of outdoor air pollution are transportation, stationary power generation, industrial and agricultural emissions, and residential heating and cooking. Generally, the burning of fuels – oil, coal, gas or wood – release elements such as particulate matter, carbon monoxide, sulphur oxides, and metals (lead, in particular) into the air. Humans breathe in these particles, which get stuck in the lung tissue and produce breathing affections and cancer on the long term.

South Africa air pollution

The University of Western Cape’s Biodiversity and Conservation Biology Department (BCB) also discusses air pollution, stating that “pollution from exhaust gases of vehicles is responsible for 60% of all air pollution and in cities up to 80%”, with lead being one of the most dangerous chemicals emitted by the transport industry. Combustion of coal is also acknowledged as a major source of air pollution leading to possible fatal effects. For South Africa in particular, one of the dangerous side effects of burning coal is acid rain, affecting stone, metal and brick elements. Highly acid rain, snow, hail or fog is produced when sulphur and nitrogen dioxides combine with the atmospheric moisture. “Coal in South Africa is rich in sulphur and the power stations in the Mpumalanga Province could be responsible for acid rain over other areas of our country”, explains the BCB.

Indeed, as announced by Greenpeace in August 2013, Witbank, a town outside of Johannesburg, has “some of the world’s most polluted air”. This can be linked with the activity of the 11 coal-fired power stations situated across Mpumalanga. Witbank is also the place where 83% of South Africa’s coal is mined.

Improving the National Ambient Air Quality

South African air is polluted by the high sulphur dioxide and particulate matter concentrations resulted from power-generation and industrial burning of coal.  This urgent matter was addressed by the most recent air quality governance approach, the Air Quality Act of 2004 and the recent National Ambient Air Quality Standards 2010. Key directions of the new approach include: Decentralisation of air quality management responsibilities; Requirements that all significant sources be identified, quantified and addressed; Setting of ambient air quality targets as goals to achieve emission reductions. The National Standards sets limits for the following airborne particles: Sulphur dioxide (SO2), Nitrogen dioxide (NO2), Particulate matter (PM 10 – 10 micrometre diameter), Ozone (O3), Benzene (C6H6), Lead (Pb) and Carbon monoxide (CO). The required date of compliance with the standards depends on each element, from “immediate” (2010) to January 1st 2015.

Autism tied to air pollution, diesel and mercury

autismResearchers seeking the roots of autism have linked the disorder to chemicals in air pollution and, in a separate study, found that language difficulties of the disorder may be due to a disconnect in brain wiring.

Researchers from Harvard University’s School of Public Health found that pregnant women exposed to high levels of diesel particulates or mercury were twice as likely to have an autistic child compared with peers in low-pollution areas. The findings, published today in Environmental Health Perspectives, are from the largest U.S. study to examine the ties between air pollution and autism.

One in 50 U.S. children are diagnosed with autism or a related disorder, according to the Centers for Disease Control and Prevention. Children with autism may be unresponsive to people, become indifferent to social activity and have communication difficulties. A separate study from Stanford University and published in Proceedings of the National Academy of Sciences is the first to suggest that weak connections between brain regions for speaking and reward may be why.

“There isn’t a lot of data to strongly point at what are the root causes of the social deficits in children with autism,” Daniel Abrams, a postdoctoral research fellow at Stanford University in California, said in a telephone interview. “We think it has this important motivation and reward component to it.”

The cause of autism isn’t known, though genetic factors are thought to be important, according to the National Institutes of Health.

The link to air pollution was initially made in 2006 by a group led by Gayle Windham at the California Department of Health Services. Another study, published in November 2012, also found links between air pollution and autism.

“People were skeptical” of the initial report from Windham’s group, said Marc Weisskopf, an author of today’s study and an associate professor of environmental health and epidemiology at Harvard University’s School of Public Health in Boston. “I went to do this in a larger setting, not at all convinced we would see anything.”

The Harvard researchers used data from the Nurse’s Health Study 2, a long-term study involving more than 116,000 nurses, begun in 1989. Within that group, the scientists looked at 325 women who had a child with autism and 22,000 women who had children without the disorder.

Using data from the Environmental Protection Agency, researchers estimated the women’s exposure to toxins, a method Weisskopf said is imperfect. Many of the compounds travel together in the air, so separating their contributions was difficult. What’s more, the EPA data is taken once every four years, so it’s an imprecise way of estimating exposure, and doesn’t take into account women’s contact from traveling to places other than their homes.

“There’s a lot of error in estimating what the mother’s exposed to,” he said. His study is large enough to suggest follow-up studies with more precise methods of detecting chemicals in the air, he said.

The study also found that including lead exposure was also associated with increased risks of autism.

About 2 percent of American school children were diagnosed with autism disorders in 2011 and 2012, according to the Centers for Disease Control and Prevention.

In the language study, brain imaging determined that the connections between brain regions for language and reward were stronger in children who don’t have the disorder than in those diagnosed with it, said Abrams. That’s important because communication problems are key diagnostic criteria for autism.

Insensitivity to human speech can affect a child’s early development, the authors said. Typical infants will listen to human speech and engage with sounds as a way to develop early language skills and emotional understanding, as well as to bond with their parents, the authors wrote.

The researchers looked at how the speech part of the brain was connected to other regions. Those with autism had weaker connections between the temporal lobe, where speech is controlled, and the dopamine reward pathway that elicits pleasurable feelings, the study found.

They also found weak links between voice regions and parts of the brain that process emotional information, Abrams said. In the future, the researchers plan to look at whether there are certain parts or types of speech that activate an autistic child’s brain, he said.

The study included 20 children with autism who were considered high functioning, with language skills and issues with communication. Their magnetic resonance imaging scans were compared with 19 children without the disorder who had similar intelligence. – bloomberg.com