Wednesday, May 8, 2013

China & North Korea: ambient particulate matter air pollution contributed to 1,270, 000 premature deaths in 2010 or about 40% of global worldwide risk

Figure 1:  A very smoggy day in Beijing, Sunday, Jan. 13, 2013 (from Yahoo News)

Industries, cars and trucks fuel or biomass combustion emit complex mixtures of air pollutants, many of which are harmful to health. Of all of these pollutants, fine particulate matter (PM) pollution has the greatest effect on human health.

Most sources of emissions are mobiles motorcars, motorcycles and sta­tionary sources such as power plants. Moreover some PM pollution is issued from fire of forest biomass exacerbated by global warming (see my 14 Sep 2012 post on Sumatra open fires).

Fine particulate matter is associated with a broad spectrum of acute and chronic illness, such as lung cancer and cardiopulmonary disease.

Worldwide, it is estimated to cause about 8% of lung cancer deaths, 5% of cardiopulmonary deaths and about 3% of res­piratory infection deaths (see WHO 2009 Global health risk report).

Particulate matter pollu­tion is an environmental health problem that affects people worldwide, but middle-income countries are disproportionately more concerned by this burden.

The Global Burden of Diseases 2010 report methodology

The Global Burden of Diseases, Injuries, and Risk Factors 2010 Study (GBD 2010) published in Dec 2012 by The Lancet, is the single largest and most detailed scientific effort ever conducted to quantify levels and trends in health. 

It is a global effort with 488 authors from 50 countries, including 26 low- and middle-income countries, led by the Institute for Health Metrics and Evaluation (IHME) at the University of Washington. GBD 2010 constitutes a unique platform to compare the magnitude of diseases, injuries, and risk factors across age groups, sexes, countries, regions, and time.

PM pollution of fine particulate matter smaller than 2.5µm concentration in the ambient air (PM2.5 expressed in µg/m3) is a useful indicator to the risk associated to an exposure of mixture of pollutant from diverse sources:  transportation emissions, windblown dust, ashes from burning of biomass or coal from power plants.

The TM5 simulation model has been used to measure the pollutants level from satellite observations and ground observations. TM5 is a complex 3-dimensional global atmospheric model which simulates the concentrations of the various atmospheric trace gases, such as greenhouse gases (carbon dioxide (CO2), methane (CH4), and nitrous oxide (N20)), chemically active species (e.g. ozone (O3)), and aerosols.

Existing studies cover mostly small concentration (up to 30 µg/m3) while much higher concentration have been recorded in Asian cities and elsewhere. The relation between health hazards and concentration is probably nonlinear.

Relative risk estimation of associated mortalities are mainly for the following outcome: ischemic heart disease, stroke, lung cancer, chronic obstructive pulmonary disease, acute lower respiratory tract infection etc.

Each risk factor is associated with a cluster of disease outcome that may cause death. Inversely each disease could proceed from a cluster of risks. Smoking and PM pollution are 2 different risks but which  outcome diseases are very similar.

Asia Pacific: ambient PM air pollution impacts on health

Outdoor PM air pollution in 2010 (see Figure 2) contributed to 1,270, 000 premature deaths in low and middle income East Asia countries (China & North Korea), which is about 40% of the global worldwide total amounting to 3,220,000 deaths. This is equivalent to the loss of 25 mil healthy years of life in China and North Korea while it is the 4th most important health risk in this area.

Figure 2 : Asia Pacific death counts from PM air pollution over 1990- 2010 (with Australasia too small to be seen)

In others low and middle income countries, PM pollution contributed to 767,000 and 164,000 premature deaths respectively in South and Southeast Asia (see Figure 2 above).

These death counts increased a lot over the last 20 years period for low and middle income countries: in East (+35% mostly China), South (+43% mostly India, Bangladesh, Pakistan ) and Southeast Asia (+50% mostly ASEAN countries).

In other high income countries, these death counts are only 88,000 while increasing only moderately over 1990-2010: in Asia Pacific (+12% Brunei, Japon, South Korea and Singapore) and Australasia  (1779 +31% Australlia, New Zealand) and as a result the death count is too small to be seen in Figure 2.

Asia Pacific: ambient PM air pollution impacts compared between various Asian countries

From the above figures we can derive the death counts per million people after averaging by each cluster of countries’ populations over 1990-2010. The following Figure 3 presents the death counts from PM air pollution per million people over 1990-2010.

Figure 3 : Asia Pacific death counts from PM air pollution as part of the overall population over 1990-2010

For low and middle income countries:

East and Southeast Asia increased by 13-15% while South Asia keeps a fixe level. 

It means that the 2 first clusters of countries have been hugely impacted by PM air pollution, while South Asia cluster of country is mostly the result of its population's size.

For high income countries:

The death counts per mil people increased very moderately +1% in Australasia and +4% in Asia Pacific high income countries.

Asia Pacific: ambient PM air pollution impact as part of the overall health risks

The 4 following Figures 4, 5, 6 & 7 present the 10 biggest health risks in 2010 as established by GBD 2010, with the 1990 values given as a comparison. The horizontal scale is also the same.

In all countries the first risk is the high blood pressure which is a physiological disorder deriving from a disturbance of normal functioning at the level of organs and systems within the human body. This risk level is about the same 1,300 to 1,400 death counts per mil people for most countries, South Asia excepted.

East Asia:

In East Asian low and middle income countries, it should be highlighted that the PM air pollution death count (918 ranked 4) is about the same as the smoking habit’s outcome (1058 ranked 3): so the PM air pollution kills as much people each year as the tobacco. 

The main risk in 1990 was the household pollution from solid fuel which in 2010 is now ranked 5 after PM air pollution.

Figure 4:  The 10 highest health risks in East Asia low and middle income countries China and North Korea from GBD 2010

South Asia:

In South Asian countries the PM air pollution death counts (486 ranked 5) is much smaller than smoking risk (ranked 3), the household air pollution is high (ranked 2) and the general profile is at a much lower level: the blood pressure death counts (ranked 1) is nevertheless half the value of East Asian countries.

Figure 5 : The 10 highest health risks in South Asia low and middle income countries from GBD 2010

Southeast Asia:

In Southeast Asian countries: apart from the PM air pollution, the 10 first risks’ profile are about the same as in East Asia for blood pressure, smoking and diet problem but at a lower levels. The PM air pollution death count is much smaller (270 ranked 9) or 3 times smaller than in East Asia. This is in relation with a more diverse grouping of countries.

Figure 6 : The 10 highest health risks in Southeast Asia low and middle income countries from GBD 2010

High income Asia Pacific countries:

In high income Asia Pacific, apart from the first 2 risks: high blood pressure and smoking, the remaining profile is different. New risks are more prevalent associated with wealthy life style: physical inactivity and high sodium at a highest level, high body mass index. The PM air pollution death count is smaller (486 ranked 9) or 2 times smaller than in East Asia.

Figure 7: The 10 highest health risks in high income Asia Pacific countries from GBD 2010