Interim target (IT) levels

Three interim target levels were set by the WHO for attaining their air quality guideline of an annual average fine particulate matter (PM2.5) concentration of 10 µg/m3. Set at progressively lower concentrations: IT-1, 35 µg/m3; IT-2, 25 µg/m3; and IT-3, 15 µg/m3.

International Agency for Research on Cancer (IARC)

The specialized cancer agency of the World Health Organization (WHO). The IARC Monographs Programme brings together international expert working groups to evaluate the scientific evidence on the carcinogenicity of exposures to specific chemicals or agents. For more information, go to the IARC website.


Age standardization

A statistical technique used to make it possible to compare death or disease rates between populations with different age profiles. Without this statistical adjustment, a population that has a larger proportion of people in older age groups, for example, would appear to have a higher rate of people dying from diseases that occur in later life (for example, heart disease) than another population with greater numbers of younger people.

Attributable burden

The share of the burden of a disease that is estimated to occur due to (“attributable to”) exposure to a particular risk factor (for example, the burden of lung disease that results from breathing air pollution versus that from smoking).



Any substance that can cause cancer.


The principle of, or relationship between, cause and effect (for example, smoking causes lung cancer).


DALY rate

The ratio of disability-adjusted life-years (DALYs) to the population (number of people) of a particular area during a particular period of time. It is calculated in the GBD project as the number of DALYs per 100,000 people per year.

Death rate

The ratio of deaths to the population (number of people) of a particular area during a particular period of time. It is calculated in the GBD project as the number of deaths per 100,000 people per year.

Disability-adjusted life years (DALYs)

Years of healthy life lost to premature (early) death and disability (illness). DALYs are the sum of years of life lost (YLLs) and years lived with disability (YLDs). (DALYs are higher when young people die compared with when old people die, because young people still had many years ahead of them.)


Fine particulate matter, or fine particles

Particulate matter less than or equal to 2.5 µm (micrometers) in aerodynamic diameter (or PM2.5).

Four world regions

Global regions used in the IHME analysis: Asia, Africa, America, and Europe.


GBD regions

Groups of countries that are geographically close and epidemiologically similar, as defined in the Global Burden of Disease (GBD) project. The “High-income North America GBD region,” for example, contains Canada and the United States of America, while the “South Asia GBD region” contains Bangladesh, Bhutan, India, Nepal, and Pakistan. See GBD regions.