Principal Means of Transportation to Work

KEY: NA = not applicable.

^a From 2004 onward, the Carpool categories are 2-person and 3+ person; 4+ person is the sum of 4-person, 5-6 persons, and 7+ persons from the source data.

^bPublic transportation refers to bus, streetcar, subway, railroad, and elevated trains for years 1989-2001, and includes ferryboats from 2002-14.

^c From 1989 to 2001, Bicycle data are included under Motorcycle.

^d Other means include ferryboats, surface trains, and van...

U.S. Passenger-Miles

KEY: N = data do not exist; R = revised; U = data are not available.

^a Data from 2007 were calculated using a new methodology developed by FHWA. Data for these years are based on new categories and are not comparable to previous years. The new category Light duty vehicle, short wheel base replaces the old category Passenger car and includes passenger cars, light trucks, vans and sport utility vehicles with a wheelbase (WB) equal to or less than 121 inches. The new category Light duty vehicle, long wheel base replaces Other 2-axle,...

Petroleum Oil Spills Impacting Navigable U.S. Waterways

KEY: N = data do not exist; R = revised.

^a Other vessels include commercial vessels, fishing boats, freight barges, freight ships, industrial vessels, oil recovery vessels, passenger vessels, unclassified public vessels, recreational boats, research vessels, school ships, tow and tug boats, mobile offshore drilling units, offshore supply vessels, publicly owned tank and freight ships, as well as vessels not fitting any particular class (unclassified).

^bOther nonvessel sources include deepwater ports, designated...

U.S. Carbon Dioxide Emissions from Energy Use by Sector

KEY:  CO2 = carbon dioxide; R = revised; Z = a value of zero, or value too small to report.

^a  Hydrocarbon Gas Liquids (HGL) includes ethane, propane, normal butane, isobutane, and natural gasoline, and their associated olefins. Excludes Liquified Natural Gas (LNG). 

Worldwide Commercial Space Launches

a Sea Launch is an international venture involving organizations in four countries and uses its own launch facility outside national borders. Their first commercial launch, in 1999, was licensed by the Federal Aviation Administration. Sea Launch filed for Chapter 11 bankruptcy protection in June 2009 and thus had no launches in the second half of the year.

Air Pollution Trends in Selected Metropolitan Statistical Areas

KEY:  AQI = Air Quality Index; R = revised.

Estimated U.S. Emissions of Sulfur Dioxide

KEY: R = revised.

^aIndustrial processes consists of chemical and allied product manufacturing, metals processing, petroleum and related industries, and other industrial processes; solvent utilization; and storage and transport. 

Estimated U.S. Emissions of Particulate Matter (PM-2.5)

KEY: R = revised.

^a Particulate matter less than 2.5 microns in size. Data include PM without condensable.

^bIndustrial processes consists of chemical and allied product manufacturing, metals processing, petroleum and related industries, and other industrial processes; solvent utilization; and storage and transportation.

Estimated U.S. Emissions of Particulate Matter (PM-10)

KEY: R = revised.

^a Fine particulate matter less than 10 microns. Data include PM without condensable.

^bIndustrial processes consists of chemical and allied product manufacturing, metals processing, petroleum and related industries, other industrial processes; solvent utilization; and storage and transport.

^c In 1985 there appears to be a spike in Miscellaneous emissions. This is likely due to a methodological change, and the EPA does not change historical data when it changes its methodology....

Estimated U.S. Emissions of Volatile Organic Compounds

KEY: R = revised.

^aIndustrial processes consists of chemical and allied product manufacturing, metals processing, petroleum and related industries, and other industrial processes; and solvent utilization, storage, and transport.