When northern Chinese politicians instigated a policy of giving free coal to residents for heating during winter months, they did not foresee that this policy would give rise to huge environmental problems in the future. Today, China is wrestling with a huge air pollution problem that many environmentalists attribute to its reliance upon coal as an energy source. Coal supplies approximately 70 percent of China’s total energy needs. As other countries have decreased their dependence upon coal as an energy source, China’s dependence continues to soar.
According to a 2007 study funded by the World Bank, 16 of the planet’s most polluted cities are in China. The city with the worst problem is Harbin, an industrial corridor in northeast China, where PM 2.5 levels routinely measure 1,000. Public health officials describe all PM 2.5 levels over 301 as “hazardous.”
Coal Consumption and PM 2.5 Particles
When coal combusts, it creates particulate matter, and many of these particulates become airborne. While larger particles can cause unsightly grime, it is the smaller particles that represent the most serious health hazard. Particles measuring 2.5 micrometers or smaller are dubbed PM 2.5 particles by scientists. PM 2.5 particles are tiny enough to be inhaled into the lungs where they can cause inflammations that trigger respiratory symptoms and exacerbate underlying cardiovascular conditions. Public health scientists say that as many as five percent of lung cancers worldwide may be traced to chronic exposure to PM 2.5 particulates.
Over time, chronic inflammations may cause cellular changes that lead to cancer and other chronic diseases. Despite a decrease in tobacco cigarette smoking, a Beijing resident’s risk of contracting lung cancer has increased by 56 percent over the past decade. Ambient particulate matter pollution is now the fourth leading cause of mortality in China. Public health officials estimate that air pollution was responsible for 1.2 million premature deaths in China in the year 2010 alone.
During the 2008 Olympics, the Chinese government made a concerted effort to clean up the country’s air. During this time, medical scientists saw a dramatic decrease among the nation’s residents in biochemical markers associated with cardiovascular disease. Medical scientists speculate that if the Chinese government made pollution restrictions permanent, Beijing residents would see their lifetime risk of developing lung cancer cut by 50 percent.
How Do PM 2.5 Particulates Affect Health?
Scientists use a metric called the Air Quality Index (AQI) to assess the effects that PM 2.5 particulates are likely to have on an individual’s health. When the AQI is 50 or below, that effect is likely to be negligible.
AQI pollution levels between 50 and 150 represent a significant risk to individuals with respiratory allergies and other environmental sensitivities, as well as to the elderly and individuals affected by cardiovascular disease. These people are advised to avoid exerting themselves outdoors. At AQI levels between 101 and 150, epidemiologists may also begin to see an increase in premature mortality rates that appear to be associated with the AQI.
As AQI levels climb, so do the health risks associated with them. When AQI rates reach 151, even healthy individuals may be advised to curtail normal outdoor activities. Sensitive individuals will be extremely affected by pollution in the air and the incidence of premature deaths will soar.
When AQI levels are 301 or higher, even previously healthy individuals may begin exhibiting respiratory symptoms associated with air pollution. Public health officials may advise all individuals to avoid outside exertion. Additionally, sensitive individuals such as people with respiratory allergies, people with cardiovascular disease, older adults and children, may be advised to avoid physical exertion altogether even in indoor spaces.