|From US EPA|
On Friday, December 14th in a conference called followed by a press release the U.S. Environmental Protection Agency, EPA, announced the reduction to the fine particle pollution, PM2.5, average annual allowed level to 12 micrograms per cubic meter (ug/m3) from 15 ug/m3. The EPA requires states to monitor air pollution to assess the healthfulness of air quality and ensure that they meet minimum air quality standards, and has some monitoring stations, but not all of the nation is monitored. The US EPA has established both annual and 24-hour PM2.5 air quality standards (as well as standards for other pollutants). The annual standard is now 12 ug/m3 (an AQI of 39). The 24-hr standard was recently revised to a level of 35 ug/m3 (an AQI of 99) and will remain unchanged. States will have until 2020 to meet the revised annual PM2.5 health standard. EPA projections show 99% of U.S. counties with monitoring stations will meet the standard with only 7 counties in California failing to meet the Annual Fine Particle Health Standard of 12 μg/m3. For coarse particles, PM10, EPA is retaining the existing 24-hour standard at 150 μg/m3 the same standard that has been in place since 1987.
Particulate matter is made up of particles that are emitted directly, such as soot and dust, as well as secondary particles that are formed in the atmosphere from reactions of precursor pollutants such as oxides of nitrogen (NOx), sulfur oxides (SOx), volatile organic compounds (VOCs), and ammonia (NH3). Particle are either directly emitted or formed in the atmosphere. Directly-emitted particles come from a variety of sources such as cars, trucks, buses, industrial facilities, power plants, construction sites, tilled fields, unpaved roads, stone crushing, and burning of wood. Other particles are formed indirectly when gases produced by fossil fuel combustion react with sunlight and water vapor. Many combustion sources, such as motor vehicles, power plants, and refineries both emit particles directly and emit precursor pollutants that form secondary particulates. Ammonium nitrate and ammonium sulfate are the principal components of secondary particulates.
Particulate matter has immediate health impacts: itchy, watery eyes, increased respiratory symptoms such as irritation of the airways, coughing or difficulty breathing and aggravated asthma. Health effects can result from both short-term and long-term exposure to particulate pollution. Exposure to particles can also trigger heart attacks and cause premature death in people with pre-existing cardiac or respiratory disease. People most sensitive to particulate pollution include infants and children, the elderly, and persons with existing heart and lung disease. The particles can travel deep into the lungs, enter the bloodstream, and penetrate into cells. Smaller particles can penetrate deepest, causing the greatest harm. Researchers are still trying to identify which types and sources of particles are most hazardous to human health. Though, particles created from combustion soot tend to be fine particles with diameters smaller than 2.5 microns (PM 2.5) which are the most dangerous because it lodges in the lungs. Dust is mostly coarser particles.
Since most counties will be in compliance with the new standard based on previous EPA regulations and auto emission standards, EPA estimates that meeting the annual fine particle standard of 12.0 μg/m3 will cost only between $53 million to $350 million, but provide health benefits worth an estimated $4 billion to $9.1 billion per year in 2020. If you would like to read about how these assessments are made see section 5 of “Regulatory Impact Analysis for theFinal Revisions to the National Ambient Air Quality Standards for ParticulateMatter” it is a window into the art and science of projecting benefits.
Currently, EPA reports that there are 66 counties of the 569 that are monitored in the nation that do not meet the 12 ug/m3 annual standard. You might want to look to see if you live in one on this list, but not every county is monitored. Prince William is not, but Fairfax is. The new PM2.5 standard is the last in a long list of regulations to improve air quality in the United States and have resulted in even the seven worst counties in the country (all in California) having significantly better air quality than the PM2.5 air monitor atop the US Embassy in Beijing reports. Below is the list of air quality rules that have resulted in the tremendous improvement in air quality from 2000-2010 in the chart above and bring the United States to the next level in clean air.
· Light-Duty Vehicle Tier 2 Rule (U.S. EPA, 1999)
· Heavy Duty Diesel Rule (U.S. EPA, 2000)
· Clean Air Nonroad Diesel Rule (U.S. EPA, 2004)
· Regional Haze Regulations and Guidelines for Best Available Retrofit Technology Determinations (U.S. EPA, 2005b)
· NOx Emission Standard for New Commercial Aircraft Engines (U.S. EPA, 2005)
· Emissions Standards for Locomotives and Marine Compression-Ignition Engines (U.S. EPA, 2008)
· Control of Emissions for Nonroad Spark Ignition Engines and Equipment (U.S. EPA, 2008)
· C3 Oceangoing Vessels (U.S. EPA, 2010)
· Hospital/Medical/Infectious Waste Incinerators: New Source Performance Standards and Emission Guidelines: Final Rule Amendments (U.S. EPA, 2009)
· Reciprocating Internal Combustion Engines (RICE) NESHAPs (U.S. EPA, 2010)
· Mercury and Air Toxics Standards (U.S. EPA, 2011)
· Cross-State Air Pollution Rule (U.S. EPA, 2011)