Glossary

G

GBD super-regions

Global Burden of Disease (GBD) regions are grouped into seven super-regions that exhibit similar cause-of-death patterns. The “Latin America and Caribbean super-region,” for example, contains the Caribbean, Central Latin America, Tropical Latin America, and Andean Latin America regions.

The seven super-regions are: High income; Latin America & Caribbean; Sub-Saharan Africa; North Africa & Middle East; South East Asia, East Asia & Oceania; South Asia; Central Europe, Eastern Europe & Central Asia. 

H

Healthy life expectancy (HALE)

The number of years that a person at a given age can expect to live in full health, taking into account the death and disability rates of the population they are part of.

I

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.

M

Morbidity

A diseased state, ill health.

Mortality

The number of deaths in a given time or place.

O

Ozone

Ozone is a gas made up of 3 oxygen atoms; it has the chemical formula O3. Ozone found at ground level, where people live and breathe, is formed by chemical reactions between nitrogen oxides and volatile organic compounds in the presence of sunlight.  For this project, ozone levels are measured in units of parts per billion (ppb) by volume. Ozone concentrations, averaged over the summer season in each region when ozone levels tend to be highest, are used to represent the exposures experienced by human populations in those regions. 

P

PM2.5

Particulate matter less than or equal to 2.5 µm (micrometers) in aerodynamic diameter. PM2.5 is measured in units of micrograms per cubic meter (µg/m3).

Population-weighted annual average

Instead of calculating average air pollution levels where all areas receive equal weight, as is typically done, population-weighted averages give weight to the areas in proportion to their population, so that greater weight is given to exposures in areas where the most people live.

Precursors

Any chemical that contributes to the formation of another compound or species (e.g. ozone or PM2.5). For example, nitrogen oxides (NOx), sulfur oxides (SOx), volatile organic compounds (VOCs), and ammonia (NH3) are all precursors for the formation of PM2.5 in the atmosphere.