Environment: Data Definitions and Sources

Nitrogen oxides emissions

2009 data.

Nitrogen oxides are a major air pollutant. Nitrogen oxides (NOx) are the sum of nitric oxide (NO) and nitrogen dioxide (NO2). The indicator is measured in kilograms per capita.

Source: OECD online database.

Sulphur oxides emissions

2009 data.

Sulphur oxides contribute to poor air quality. The emissions are mostly formed during industrial processes. The indicator is measured in kilograms per capita.

Source: OECD online database.

VOC emissions


This indicator is a measure of kilograms of volatile organic compounds emissions per capita. Volatile organic compounds contain one or more carbon atoms with high vapour pressures; they evaporate readily into the atmosphere to form smog. The indicator is measured in kilograms per capita.

Source: OECD online database.

PM10 concentration

2009 data.

This indicator measures particulate matter in micrograms per cubic metre. Particulate matter consists of airborne particles that contribute to pollution. PM10 means that the particulate matter has a mass median diameter less than 10 micrograms.

Source: World Bank online database

Municipal waste generation

2009 data for all countries except 2008 data for Canada and Japan. Where possible, missing historical data have been interpolated between two available data points.

This indicator measures the amount of municipal waste generated per capita, in kilograms. It includes waste that has been disposed of, recycled, or composted from residential and non-residential sources. Residential non-hazardous waste includes solid waste produced by all residences and picked up by the municipality (either using its own staff or through contracting firms), as well as waste from residential sources that is self-hauled to depots, transfer stations, and disposal facilities. Non-residential non-hazardous solid waste is generated by all sources except the residential waste stream. It includes industrial materials generated by manufacturing and by primary and secondary industries and managed off-site from the manufacturing operation. It also includes commercial materials generated by commercial operations such as shopping centres, restaurants, and offices. And it includes institutional materials generated by institutional facilities such as schools, hospitals, government facilities, seniors’ homes, and universities. However, it does not include waste from construction, renovation, and demolition sources.

Source: OECD online database.

Canadian data source is Statistics Canada, Waste Management Industry Survey: Business and Government Sectors, Catalogue no. 16F0023X (Ottawa: Statistics Canada, 2008).

Water Quality Index

Most recent year available.

The Water Quality Index measures dissolved oxygen, pH, conductivity, total nitrogen, and total phosphorus. The index ranges from 0 (lowest quality) to 100 (highest quality).

The water quality parameters chosen by the Yale Center to be included in the Environmental Performance Index were selected for two reasons. First, they are good indicators of specific, globally relevant issues (such as eutrophication, nutrient pollution, acidification, and salinization). Second, they are the most consistently reported. Because water quality is a function of a number of different physical and chemical parameters measured during routine water quality monitoring, a global index of the general status of water quality, ranked by country, is best developed as a composite index of several key parameters.

Source: Yale Center for Environmental Law & Policy, Environmental Performance Index.

Water withdrawals

2009 data or most recent year available.

Water withdrawals is measured by annual freshwater withdrawals, measured in cubic metres per capita. Withdrawals refer to the gross amount of water extracted from any source, either permanently or temporarily, for a given use.

Source: OECD online database.

Threatened species

Most recent year available.

This indicator is a composite index that measures threatened mammals, threatened birds, threatened vascular plants, and threatened freshwater fish as a proportion of known species. The index is created by taking an average of normalized scores for the three sub-indicators.

Sources: OECD online database.

Forest cover change

2000–2010 data.

This indicator measures the change between 2005 and 2010 of forest cover as a percentage of total land area.

Source: World Bank online database.

Use of forest resources

2000s data.

Use of forest resources measures a country’s timber harvest as a per cent of the forest’s annual growth. It is a measure of the intensity of use of forest resources.

Source: OECD, Environment at a Glance: OECD Environmental Indicators 2005 (Paris: OECD, 2005).

Marine Trophic Index

2000–2006 data.

This indicator measures the change in the Marine Trophic Index between 2000 and 2006. The Marine Tropic Index measures the degree to which countries are “fishing down the food chain,” with fish catches increasingly consisting of smaller fish that are lower in the food chain.

The Marine Trophic Index is usually calculated from data on commercial fish landings. Each species of fish or invertebrate is assigned a number dependent upon its position in the food chain: herbivores such as many invertebrate species are given a low number, whereas top predators such as hake and whiting are given a higher number. The average value for all species gives an index measuring the complexity of the food chain. A decrease in the index signifies an increasing proportion of the catch consisting of invertebrates and fish that are low in the food chain. Possible consequences of reduced food chain complexity are a loss of ecosystem resilience to environmental pressures such as climate change and threats to the supply of fish for human consumption.

Source: Fisheries Centre. University of British Columbia. The Sea Around Us.

GHG emissions

2009 data.

Total GHG emissions excluding land use and land use change and forestry (LULUCF) divided by population. The unit of measurement is tonnes of carbon dioxide (CO2) equivalent per capita.

LULUCF refers to changes in GHG emissions due to human activities related to land use, land management, and forestry. This includes wildfires, controlled burning, and cropland conversions. LULUCF is excluded from the GHG emissions data used here because of significant fluctuations in annual LULUCF emissions.

Source: United Nations Framework Convention on Climate Change (UNFCCC).

Low-emitting electricity production

2011 data.

This indicator measures the share of low-emitting electricity production in total domestic electricity production. Low-emitting electricity production includes nuclear, hydro, geothermal, wind, solar, and other renewables.

Source: International Energy Agency, Monthly Electricity Statistics.

Energy intensity

2009 data.

Energy intensity measures total primary energy supply per unit of gross domestic product (GDP) measured in tonnes of oil equivalent (toe) per US$1,000 GDP. 

Source: International Energy Agency.