Few things are as important as the quality of the air we breathe. A few Virginia regions have room for improvement, and the state's emission of common, hazardous, and greenhouse gas pollutants runs considerably higher than the national average. But overall air quality in the Commonwealth has risen significantly in recent years.
Why is This Important?
Poor air quality causes increased deaths, especially among the very young and the very old. It reduces water quality, contributes to climate change, and damages forest resources, agriculture, buildings, and infrastructure. It also makes Virginia a less attractive place to live, do business in, or visit — factors that have consequences for both the economy and the quality of life.
How is Virginia Doing?
Particle pollution is a complex mixture of both solid and liquid particles of varying sizes; the most dangerous kind are the tiny particulates found in soot, dust, smoke and fumes caused by burning coal, oil, diesel, and other fuels.
Virginia's air quality has markedly improved in recent years. For example, residents' average exposure to fine particulates -- particles of dust, soot, aerosols, and dust fine enough to be inhaled -- has decreased every year over the past decade and more. The current average annual PM2.5 National Ambient Air Quality Standard (NAAQS) is 12 micrograms per cubic meter. Average exposure in Virginia for 2015 was 8.3 micrograms of fine particles per cubic meter -- lower than the United States average (9.5) and ranking 20th in the nation. Among peer states, Maryland (9.6), Tennessee (9.1), and North Carolina (8.7) all had higher average exposure levels in 2015. Wyoming (5.0) had the lowest in the US.
Air quality has also generally improved in each of Virginia's regions from 2003 to the most recent year available, 2012. The lowest average exposure in 2012 was found in the Eastern (8.2) and Hampton Roads (8.5) coastal regions. The highest average exposure was in the Northern region (9.3).
Smog / Ozone Pollution
Ground level ozone (the main ingredient in smog) is a colorless gas formed by the reaction of sunlight with vehicle emissions, gasoline fumes, solvent vapors, and power plant and industrial emissions. Traffic-related air pollution is a major factor in local air quality and is known to contribute to early onset of childhood asthma, other respiratory problems, and cardiovascular disease.
Approximately 0.9% of Virginia's residents live in close proximity to a major road corridor, such as an interstate highway or expressway and are at most risk of exposure to vehicle-created pollutants. Peer state Maryland has a higher percentage of residents living near major roadways (1.1%), while Tennessee (0.2%) and North Carolina (0.1%) are considerably lower. Virginia is below the national average of 1.1% and ranks 36th among US states.
Based in part on over 1,000 post-2008 studies showing that ozone levels greatly affect public health (especially for at-risk groups like the young, the elderly, and those with COPD and asthma), in October 2015 the EPA updated the acceptable limits for ground-level smog: down to 70 micrograms per billion from the 75 ppb levels set in 2008.
Virginia has also significantly reduced the number of days when the federal ozone standard have been exceeded -- dropping from 341 days per 3-year average in 2004-06 to just 13 days across 2013-15. Among Virginia's regions, the highly congested Northern region continues to have the poorest air quality, with an average of 9.3 days exceeding the ozone standard over that same 2013-15 period.
Additional pollutants, including some that are considered especially hazardous or toxic, also seep into Virginia's air. As with water pollution, air pollutants are categorized as coming from one of two sources: point sources, where the cause has a single known point of origin (such as a factory smokestack); and non-point sources, where pollutants come from diffuse origins, as with automobiles or farms. Understandably, it is easier to control pollution from point sources than from non-point ones.
Emissions of the most common air pollutants (referred to as "criteria pollutants" by the Clean Air Act and the EPA) have decreased markedly in recent years, with point sources such as power plants and factories accounting for a declining share of total emissions. In 2006, these permitted sources emitted a total of 489,000 tons of criteria pollutants statewide, which fell to a low of 202,000 tons in 2012 before increasing slightly to 222,000 tons by 2014. These changes track closely with the downsizing of manufacturing activity and general economic conditions in the state.
Although Volatile Organic Compounds and Ammonia are not criteria pollutants, they do contribute to the formation of such, and are therefore regulated and tracked by the Virginia Department of Environmental Quality -- and included in the graph above.
Looking at all sources of criteria pollutants (point sources as well as non-point sources like automobiles, businesses, and farms), Virginia's per capita average in 2011 was 0.39 tons, a drop from 0.49 tons in 2008. The Commonwealth's per capita criteria pollutant total was considerably lower than the national average of 0.62 tons. It was also lower than both peer states Tennessee (0.51) and North Carolina (0.46), but not as low as Maryland (0.24). The national leader for emissions of critera pollutants in 2011 was New Jersey, with 0.14 tons per capita.
Among Virginia's regions, the more rural areas -- Eastern, Southside, Southwest, and Valley -- saw the highest per capita emissions for criteria pollutants in 2011: 1.0, 0.93, 0.78, and 0.70 tons, respectively. More urbanized regions (Northern, Hampton Roads, and Central) had lower per capita emission rates, led by the Northern region with 0.19 tons per capita. However, all regions in the state saw a reduction in common pollutant emissions from their 2008 levels.
Virginia also emits other types of air pollution, including hazardous air pollutants (HAP) such as heavy metals and greenhouse gas pollutants (GHG). In 2011, Virginia's hazardous emissions were 33.5 pounds per capita, an increase from 31.9 pounds in 2008. Greenhouse gas emissions were 6.0 tons per capita in 2011, a drop from the 6.9 tons per capita seen in 2008.
These 2011 figures were lower than peer states North Carolina (per capita HAP of 42.2 pounds and GHG of 7.0 tons), and Tennessee (per capita HAP of 46.7 pounds and GHG of 8.2 tons), but not as low as Maryland, with a per capita HAP of 16.1 pounds and GHG of 5.9 tons.
Virginia's emissions were also lower than the national averages for each category of pollutant (per capita HAP of 58.2 pounds and GHG of 7.3 tons). Leading state New Jersey had a per capita hazardous pollution rate of just 9.4 pounds, while Rhode Island led the country on greenhouse gas emissions, with 4.4 tons per person.
Among Virginia regions, the Northern (HAP of 12.1 pounds, GHG of 4.7 tons) and Hampton Roads regions (HAP of 20.5 pounds, GHG of 4.8 tons) again had the lowest per capita emission rates in 2011, compared to 2008. The Eastern region had the highest HAP emission rate at 107.7 pounds per capita, while the Valley saw the highest greenhouse gas emissions at 9.2 tons per capita.
Mercury exists in various forms: elemental / inorganic (to which people may be exposed through their occupation); and organic (e.g., methylmercury, to which people may be exposed through their diet, as with eating fish which have ingested it). These forms of mercury differ in their degree of toxicity and in their effects on living organisms.
Mercury released as a by-product of human activity is a particularly harmful heavy metal whose presence in our modern environment is mainly due to coal- and oil-fired power plants. Even exposure to relatively small quantities in air, water, and food can build up in organisms and cause adverse health effects such as neural impairment, respiratory failure, kidney damage, and possibly even cancer. Because of these dangers, the pollutant is stringently monitored and regulated.
Virginia's mercury emissions dropped from 0.00038 pounds per capita in 2008 to 0.00023 pounds in 2011. This decrease improved the state's standing from 22nd nationally to 18th. Virginia's mercury emissions in 2011 were lower than Tennessee (0.00048 pounds per capita), but higher than both North Carolina (0.00020 pounds) and Maryland (0.00015 pounds). New Jersey led all states with just 0.00007 pounds of mercury per capita.
Among Virginia's regions, Hampton Roads had the highest mercury emissions in 2011 at 0.00050 pounds per capita; the most improved region was Central, which dropped from 0.0010 pounds per capita in 2008 to 0.00034 pounds in 2011. 2011's lowest mercury emissions were found in the Northern (0.00004) and Valley (0.00006) regions.
What Influences Air Quality?
Heavy automobile use is one chief contributor to air pollution in the US; coal-burning plants are another. Increased efficiency of automobile engines, growth in the use of hybrid vehicles, and more use of alternative modes of travel can all contribute to better air quality. Similarly, wider use of clean energy sources for generating electricity and other needs can also have major impact. All have the attendant benefit of helping to reduce greenhouse gases, which contribute so heavily to climate change. Finally, global atmospheric circulation can cause emissions from other states and even other countries to affect Virginia.
Certain emissions (from cars, coal plants, etc.) are subject to reductions or caps mandated by state, federal, and international laws and obligations. Regulations on emission rates need to be tightened periodically to maintain air quality when economic activity increases or when it becomes clear that older standards are no longer adequate.
For example, since 2008, US standards for regulating vehicle fuel efficiency and emissions (which had generally remained static since the 1970s) rose significantly, leading both domestic and foreign automakers to develop cleaner engines and hybrid alternatives for many models in their fleets of cars and trucks. As a result, vehicle fuel economy rose an average of 3 mpg from 2008 to 2014, while average CO2 emissions decreased 58 grams per mile over the same period. At the same time, total sales of hybrid vehicles rose from 315,688 in 2008 to 507,272 in 2014, an increase of 62 percent, with US automakers also upping their share of the overall hybrid market by nearly 42 percent.
The latest EPA standards regulating mercury emissions from power plants were proposed in 2011 and finalized in 2014; these lower the acceptable ranges from 0.04 to 0.0001 pounds of mercury pollutant per gigawatt-electric output, depending on the age and type of plant processes used.
What is the State's Role?
Air quality standards are established by the federal government via the Clean Air Act and are the main factor behind the steady improvements in air quality the US has seen since the law was first passed in 1970. The Virginia Department of Environmental Quality is charged with enforcing these federal standards in the Commonwealth.
What Can Citizens Do?
Individuals and groups are strongly encouraged to be active participants in resource management. Reducing smog and particulate emissions through increased use of hybrid vehicles is just one place to start. To learn more about Virginia's environment, stewardship and public participation opportunities, and the partners engaged in conservation, please visit the Dept. of Conservation and Recreation's Environmental Education pages or the Virginia Conservation Network.
State rankings are ordered so that #1 is understood to be the best.
Data Definitions and Sources
Virginia Ozone Exceedence
Virginia Department of Environmental Quality, www.deq.virginia.gov/Programs/Air.aspx
- Estimates provided by United Health Foundation, America's Health Rankings are used to estimate state particulate exposure (2.5 micron and smaller), measured in micrograms of fine particulate per cubic meter:
- National data from the CDC,
Population-weighted average exposure to fine particulates (2.5 micron and smaller) measured in micrograms of fine particulate per cubic meter. The computed statewide average values differ from America's Health Rankings estimates because of methodological differences.
County monitor and modeled data from the EPA Environmental Public Health Tracking Network is used to estimate regional particulate exposure.
Residential Proximity to Major Roadways
US Department of Transportation
Transportation and Health Indicators
Percentage of people who live within 200 meters of a high traffic roadway that carries over 125,000 vehicles per day (2010).
Point and Nonpoint Source Emissions
- Department of Environmental Quality,
Criteria pollutants include Carbon Monoxide (CO), Nitrous Oxide (NO2), Lead (PB), Sulfur Dioxide (S02), and fine particulate matter (PM 10 and PM 2.5). The emission inventory also tracks substances that contribute to the formation of criteria air pollutants: Volatile Organic Compounds (VOC) and Ammonia (NH3).
- State and Regional Criterion, Hazardous, and Greenhouse Total Emissions and Mercury Emissions
Environmental Protection Agency, National Emissions Inventory (NEI)
The National Emissions Inventory is conducted every three years. The 2014 inventory is still in progress.
The Clean Air Act categorizes 188 air toxins as "hazardous air pollutants." These pollutants are known to cause serious health effects such as cancer and birth defects and include heavy metals such as mercury, cadmium, chromium, and lead as well as many other pollutants such as dioxins and benzene.
Greenhouse gas air pollutants contribute to greenhouse warming and include carbon dioxide, methane, nitrous oxide, hydroflourocarbons, perfluorocarbons, and sulfur hexafluoride.
Standards and Regulations
- Center for Climate and Energy Solutions
Federal Vehicle Standards, www.c2es.org/federal/executive/vehicle-standards
- Environmental Protection Agency, Light-Duty Automotive Technology, Carbon Dioxide Emissions, and Fuel Economy Trends: 1975-2015
- US Dept. of Transportation, Bureau of Transportation Statistics, Table 1-19: Sales of Hybrid Vehicles in the United States
- Natural Resources Defense Council, Summary of Recent Mercury Emission Limits for Power Plants in the United States and China (pdf)
See the Data Sources and Updates Calendar for a detailed list of the data resources used for indicator measures on Virginia Performs.