Lung Cancer Causes – Air Pollution

Lung Cancer Causes – Air Pollution

Air pollution caused by industry, power plants and vehicles of various types raises the likelihood of developing Lung Cancer in persons who are exposed polluted air. Approximately one-percent of the deaths from Lung Cancer are attributed to breathing polluted air. Prolonged exposure to air pollution may carry risks for developing Lung Cancer which are similar to Passive Smoking; according to experts. Air pollution can contain trace amounts of diesel exhaust, coal products, and other industrial substances.

Air pollution is a significant environmental risk factor for lung cancer. For every increase of 5 μg/m3 of particulate matter (PM) smaller than 2.5 μm in diameter (PM2.5) in the environment, the risk of lung cancer rises by 18%; for every elevation of 10 μg/m3 in PM smaller than 10 μm (PM10), the risk increases by 22% (Raaschou-Nielsen et al., 2013). Anthropogenic PM2.5 is associated with 220,000 lung cancer mortalities annually (Anenberg et al., 2010). Based on sufficient evidence of carcinogenicity, the International Agency for Research on Cancer (IARC) Working Group recently classified outdoor air pollution and related PM as Group 1 carcinogenic to humans (Loomis et al., 2013). However, the carcinogenic mechanism of air pollution remains to be dissected using systematic approaches.

Air pollution is killing about 4,400 people in China every single day, according to a new study. Exposure to air pollution has many impacts across the lifespan and has now been linked to survival of patients after being diagnosed with lung cancer, the most commonly diagnosed cancer over the past several decades.

People most susceptible to severe health problems from air pollution are:

• Individuals with heart disease - such as coronary artery disease or congestive heart failure

• Individuals with lung disease - such as asthma, emphysema or chronic obstructive pulmonary disease (COPD)

• Pregnant women

• Outdoor workers

• Children under age 14, whose lungs are still developing

• Athletes who exercise vigorously outdoors

Air pollution is a major environmental issue affecting people across the world. According to the World Health Organisation(WHO), more than 2 million people worldwide die every year from air pollution. Of all the air pollutants, fine particulate matter (PM) is one of the most hazardous pollution for the human health. The particulate matter causes about 9% of lung cancer deaths worldwide, 5% of cardiopulmonary deaths and about 1% of respiratory infection deaths. According to the WHO, there is mounting evidence that concentration of particulate matter is increasing in Asia. Particulate matter mostly originates from dust storms, grassland fires, burning of fossil fuels in vehicles, power plants, but also various industrial plants generate significant amounts of particulates. The interactive map shows that South Asia is badly hit by pollution caused by particulate matter. While Pakistan has the highest concentration of particulate matter, countries like Bangladesh, Nepal and India are placed by the WHO in a category called “unhealthy for the sensitive people”. That means people in these countries suffering from respiratory and heart disease, as well as elderly and children should limit outdoor exertion. Air pollution in China is as bad, if not worse, than in India but according to the WHO,the particulate matter concentration in China and in countries such as Myanmar, Sri Lanka, South Korea and Indonesia remains moderate. There is the least presence of particulate matter in Philippines, Malaysia, Thailand, Singapore and Japan.

In a groundbreaking Oct. 17 announcement, the International Agency for Research on Cancer (IARC), an agency of the World Health Organization, classified outdoor air pollution as a known cause of lung cancer. The agency also found that particulate matter (PM), a major component of air pollution better known as “soot,” is a known cause of lung cancer.  After an extensive review of more than 1,000 scientific studies from five continents, a committee of some of the world’s leading experts on air pollution and health convened by the IARC Monographs Programme concluded that there is sufficient evidence that exposure to outdoor air pollution causes lung cancer. Though IARC has previously evaluated the health impacts of various components of outdoor air pollution, such as diesel engine exhaust, metals, and solvents, this is the first time that outdoor air pollution in general has been classified as a cause of cancer.

High air pollution levels can cause immediate health problems:

• Aggravated cardiovascular and respiratory illness

• Added stress to heart and lungs, which must work harder to supply the body with oxygen

• Damaged cells in the respiratory system

Researchers from Berkeley Earth, a California-based climate research organization, calculated that about 1.6 million people in China die every year from health issues caused by the country’s notoriously polluted air.

“We thought that if ambient air pollution is a carcinogen that can drive lung cancer development, then exposure to air pollution in patients already diagnosed with lung cancer could promote the progression of their disease through the same biological pathways,” said Sandrah Eckel, assistant professor of preventive medicine at the Keck School of Medicine of USC and lead author of the research. Eckel and colleagues at the Keck School decided to more closely explore the question of whether lung cancer survival times might be affected by air pollution.

The particulate matter represents a complex mixture of solid and liquid particles suspended in the air, many of which are hazardous. These particles are either directly emitted into the air by sources such as smoke, dust, pollen, or formed in the atmosphere by transformation of emitted gases. The particulate matter can adversely affect human health and also have an impact on climate and precipitation. On the basis of size, the particulate matter is divided into two categories. The particles up to 10 micrometers in size are called PM 10 and smaller particles of 2.5 micrometer in size are called PM2.5. The WHO has measured outdoor air pollution caused by both types of the particulate matter and according to these findings, air can be contaminated by a range of different particles of which many can harm our health, especially very small particles that enter into the lungs and bloodstream and cause the most serious health problems. In Asia, like in other regions of the world, pollution caused by particulate matter is spreading to new areas. The graph, based on the data obtained from the WHO, ranks Asian countries according to the PM10 level in the air. As the data suggests, Pakistan is the most polluted country in the region in terms of particulate matter concentration in the air. It is followed by Bangladesh, India, Nepal, China, Myanmar, Sri Lanka, South Korea, Indonesia, Philippines, Malaysia, Thailand, Singapore and Japan.

The IARC evaluation found strong scientific evidence of an increased risk of lung cancer with increasing exposure to air pollution in general and issued a similar finding for particulate matter. Although the composition of air pollution and levels of exposure can vary dramatically between locations worldwide, the IARC conclusions apply to all regions of the world. The IARC assessment of the link between PM and lung cancer contrasts with findings from the U.S. Environmental Protection Agency’s (EPA) 2009 assessment of the PM health science,  which classified the PM-lung cancer scientific evidence as only “suggestive of a causal relationship.”

Long-term exposure to polluted air can have permanent health effects:

• Accelerated aging of the lungs

• Loss of lung capacity

• Decreased lung function

• Development of diseases such as asthma, bronchitis, emphysema, and possibly cancer

• Shortened life span

According to the study, more than one-third of the Chinese population regularly breathe air that would be considered “unhealthy” by U.S. standards.

Their research, published this month in Thorax, shows that the length of time that lung cancer patients live after diagnosis varies depending on their exposures to regional pollution. Researchers found that the median survival for people diagnosed with early stage lung cancers who lived in areas with high levels of regional pollution was approximately three years shorter than for people who lived in areas with lower levels of pollution.

Air pollution in some Asian cities is so bad that at times, the cities are enveloped by a blanket of smog that impedes visibility. According to the WHO,air pollution has worsened in Asian cities in recent years and presents a threat to human health. In many cities the levels of fine particulate matter - a key pollutant in terms of its impact on human health - are exceeding the critical limit (as defined by the WHO), specifically in densely populated, fast-growing and less developed countries like China, India, Pakistan and Bangladesh. Even in small Asian cities like Kathmandu, the particulate matter level exceeds the most lenient of several targets recommended by the WHO. Over the last few years, China has been in the news for heavy pollution in its cities with the skies being completely blanketed by smog. India and Pakistan, however, have the dubious distinction of having the most polluted cities in the region. If we take a look at the statistics concerning capital cities in Asia, the air pollution caused by the particulate matter is worst in Delhi. It is closely followed by Islamabad, Dhaka, Beijing and Kathmandu.

The IARC findings have significant implications for U.S. air pollution control efforts. The EPA sets air quality standards to protect public health based on assessments of the health effects of individual pollutants rather than outdoor air pollution in general.  Air pollution control rules are then developed for specific sources of these individual pollutants in order to achieve the health-based standards.

As The New York Times notes, air pollution — particularly exposure to fine airborne particles — can cause a variety of health problems, including asthma, lung cancer, heart disease and stroke. The World Health Organization said last year that 7 million people die annually because of exposure to polluted air.

“We focused on California, since there are a wide range of air pollution levels here and one of the largest and longest running air quality monitoring networks and cancer registry system in the U.S.,” Eckel said.

Air pollution is one of the main causes of premature deaths in the world. Of all major global health risks, outdoor air pollution in the form of fine particles is found to be much more dangerous for public health than previously known - contributing annually to over 2 million premature deaths worldwide. The WHO global study ranks air pollution as one of the top 10 killers in the world, with 65 percent of all air pollution deaths occurring in Asia. In 2010 alone, particulate matter pollution was the fourth-leading risk factor for deaths in China, behind high blood pressure and smoking. Across the region, increasing levels of particulate matter are causing higher numbers of premature deaths. The graph reveals the human toll due to outdoor air pollution in 2008, which is the latest comparative data available. A record number of people have died due to air pollution in the region. In the year 2008 alone, over half-million people have died in China and India. Other countries in the region have also suffered heavily from air pollution. On top of that, the future looks very bleak. By 2050, urban air pollution is estimated to cause up to 3.6 million premature deaths worldwide each year, mostly in China and India.

However, in the real world, we are exposed to a toxic soup of various different air pollutants and chemical mixtures, which interact and combined can have a greater health impact than each of the individual components. This concept was recognized more than 40 years ago and incorporated by Congress into the Clean Air Act of 1970, which provides the foundation of today’s air pollution control efforts. In providing instruction to EPA for developing air pollutant health assessments, Congress expressly required EPA to consider “the types of air pollutants which, when present in the atmosphere, may interact with such pollutant to produce an adverse effect on public health or welfare” (emphasis added).

China has struggled for years to control its air pollution problems, which are primarily caused by the burning of coal in factories and power plants, as well as vehicle use.

Eckel and her team of researchers looked at lung cancer data from over 350,000 patients in the California Cancer Registry who were diagnosed with lung cancer between 1988-2009. From the extensive and detailed dataset, the team assigned air pollution exposure levels based on the average exposure at the patient’s residence at diagnosis.

Given the generally accepted scientific consensus that even very low levels of exposure to environmental pollution increases the risk of cancer, the IARC findings suggest that reductions in U.S. air pollution beyond levels set as “safe” for individual pollutants, especially for particulate matter and transportation-related pollutants that were the focus of many of the reviewed studies, would provide additional public health benefits in avoided lung cancers.

In April, Greenpeace reported that, of 360 cities in China, less than 10 percent had successfully met national air quality standards in the first quarter of 2015.