Particulates

From Wikipedia, the free encyclopedia
  (Redirected from Particulate emissions)
Jump to: navigation, search
This article is about particles suspended in air. For general discussion of particulate types, see Particle#Distribution of particles.
For other uses, see Particulates (disambiguation).
This diagram shows types, and size distribution in micrometres, of atmospheric particulate matter.
This animation shows aerosol optical thickness of emitted and transported key tropospheric aerosols from 17 August 2006 to 10 April 2007, from a 10 km resolution GEOS-5 "nature run" using the GOCART model.[1][2] (click for more detail)
* green: black and organic carbon
* red/orange: dust
* white: sulfates
* blue: sea salt
Movie map of distribution of aerosol particles, based on data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite.
* Green areas show aerosol plumes dominated by larger particles.
* Red areas show aerosol plumes dominated by small particles.
* Yellow areas show where large and small aerosol particles are mixing.
* Gray shows where the sensor did not collect data.

Atmospheric particulate matter – also known as particulate matter (PM) or particulates – is microscopic solid or liquid matter suspended in the Earth's atmosphere. The term aerosol commonly refers to the particulate/air mixture, as opposed to the particulate matter alone.[3] Sources of particulate matter can be man-made or natural. They have impacts on climate and precipitation and adversely affect human health. Subtypes of atmospheric particle matter include suspended particulate matter (SPM), respirable suspended particle (RSP; particles with diameter of 10 micrometres or less), fine particles (diameter of 2.5 micrometres or less), ultrafine particles, and soot.

The IARC and WHO designate airborne particulates a Group 1 carcinogen. Particulates are the deadliest form of air pollution due to their ability to penetrate deep into the lungs and blood streams unfiltered, causing permanent DNA mutations, heart attacks, and premature death.[4] In 2013, a study involving 312,944 people in nine European countries revealed that there was no safe level of particulates and that for every increase of 10 μg/m3 in PM10, the lung cancer rate rose 22%. The smaller PM2.5 were particularly deadly, with a 36% increase in lung cancer per 10 μg/m3 as it can penetrate deeper into the lungs.[5]

Sources of atmospheric particulate matter[edit]

Some particulates occur naturally, originating from volcanoes, dust storms, forest and grassland fires, living vegetation, and sea spray. Human activities, such as the burning of fossil fuels in vehicles, power plants and various industrial processes also generate significant amounts of particulates. Coal combustion in developing countries is the primary method for heating homes and supplying energy. Because salt spray over the oceans is the overwhelmingly most common form of particulate in the atmosphere, anthropogenic aerosols—those made by human activities—currently account for about 10 percent of the total mass of aerosols in our atmosphere.[6]

Composition[edit]

The composition of aerosols and particles depends on their source. Wind-blown mineral dust[7] tends to be made of mineral oxides and other material blown from the Earth's crust; this particulate is light-absorbing.[8] Sea salt[9] is considered the second-largest contributor in the global aerosol budget, and consists mainly of sodium chloride originated from sea spray; other constituents of atmospheric sea salt reflect the composition of sea water, and thus include magnesium, sulfate, calcium, potassium, etc. In addition, sea spray aerosols may contain organic compounds, which influence their chemistry.

Secondary particles derive from the oxidation of primary gases such as sulfur and nitrogen oxides into sulfuric acid (liquid) and nitric acid (gaseous). The precursors for these aerosols—i.e. the gases from which they originate—may have an anthropogenic origin (from fossil fuel or coal combustion) and a natural biogenic origin. In the presence of ammonia, secondary aerosols often take the form of ammonium salts; i.e. ammonium sulfate and ammonium nitrate (both can be dry or in aqueous solution); in the absence of ammonia, secondary compounds take an acidic form as sulfuric acid (liquid aerosol droplets) and nitric acid (atmospheric gas), all of which may contribute to the health effects of particulates.[10]

Secondary sulfate and nitrate aerosols are strong light-scatterers.[11] This is mainly because the presence of sulfate and nitrate causes the aerosols to increase to a size that scatters light effectively.

Organic matter (OM) can be either primary or secondary, the latter part deriving from the oxidation of VOCs; organic material in the atmosphere may either be biogenic or anthropogenic. Organic matter influences the atmospheric radiation field by both scattering and absorption. Another important aerosol type is elemental carbon (EC, also known as black carbon, BC): this aerosol type includes strongly light-absorbing material and is thought to yield large positive radiative forcing. Organic matter and elemental carbon together constitute the carbonaceous fraction of aerosols.[12] Secondary organic aerosols, tiny "tar balls" resulting from combustion products of internal combustion engines, have been identified as a danger to health.[13]

The chemical composition of the aerosol directly affects how it interacts with solar radiation. The chemical constituents within the aerosol change the overall refractive index. The refractive index will determine how much light is scattered and absorbed.

The composition of particulate matter that generally causes visual effects such as smog consists of sulfur dioxide, nitrogen oxides, carbon monoxide, mineral dust, organic matter, and elemental carbon also known as black carbon or soot. The particles are hydroscopic due to the presence of sulfur, and SO2 is converted to sulfate when high humidity and low temperatures are present. This causes the reduced visibility and yellow color.[14]

Size distribution of particulates[edit]

Aerosol particles of natural origin (such as windblown dust) tend to have a larger radius than human-produced aerosols such as particle pollution. The false-color maps in the third image on this page show where there are natural aerosols, human pollution, or a mixture of both, monthly.

Among the most obvious patterns that the size distribution time series shows is that in the planet’s most southerly latitudes, nearly all the aerosols are large, but in the high northern latitudes, smaller aerosols are very abundant. Most of the Southern Hemisphere is covered by ocean, where the largest source of aerosols is natural sea salt from dried sea spray. Because land is concentrated in the Northern Hemisphere, the amount of small aerosols from fires and human activities is greater there than in the Southern Hemisphere. Over land, patches of large-radius aerosols appear over deserts and arid regions, most prominently, the Sahara Desert in north Africa and the Arabian Peninsula, where dust storms are common. Places where human-triggered or natural fire activity is common (land-clearing fires in the Amazon from August–October, for example, or lightning-triggered fires in the forests of northern Canada in Northern Hemisphere summer) are dominated by smaller aerosols. Human-produced (fossil fuel) pollution is largely responsible for the areas of small aerosols over developed areas such as the eastern United States and Europe, especially in their summer.[15]

Satellite measurements of aerosols, called aerosol optical thickness, are based on the fact that the particles change the way the atmosphere reflects and absorbs visible and infrared light. As shown in the seventh image on this page, an optical thickness of less than 0.1 (palest yellow) indicates a crystal clear sky with maximum visibility, whereas a value of 1 (reddish brown) indicates very hazy conditions.[16]

Deposition processes[edit]

In general, the smaller and lighter a particle is, the longer it will stay in the air. Larger particles (greater than 10 micrometers in diameter) tend to settle to the ground by gravity in a matter of hours whereas the smallest particles (less than 1 micrometer) can stay in the atmosphere for weeks and are mostly removed by precipitation. Diesel particulate matter is highest near the source of emission. Any info regarding DPM and the atmosphere, flora, height, and distance from major sources would be useful to determine health effects.

Control technologies[edit]

Main article: Dust collector
Cross-section of a NIOSH P95 filter pad used in metalworking operations. Personal breathing protection equipment typically uses disposable cartridges with mechanical filtration devices

Particulate matter emissions are highly regulated in most industrialized countries. Due to environmental concerns, most industries are required to operate some kind of dust collection system to control particulate emissions. These systems include inertial collectors (cyclonic separators), fabric filter collectors (baghouses), wet scrubbers, and electrostatic precipitators.

Cyclonic separators are useful for removing large, coarse particles and are often employed as a first step or "pre-cleaner" to other more efficient collectors. Well-designed cyclonic separators can be very efficient in removing even fine particulates, and may be operated continuously without requiring frequent shutdowns for maintenance.

Fabric filters or baghouses are the most commonly employed in general industry.[17] They work by forcing dust laden air through a bag shaped fabric filter leaving the particulate to collect on the outer surface of the bag and allowing the now clean air to pass through to either be exhausted into the atmosphere or in some cases recirculated into the facility. Common fabrics include polyester and fiberglass and common fabric coatings include PTFE (commonly known as Teflon©). The excess dust buildup is then cleaned from the bags and removed from the collector.

Wet scrubbers pass the dirty air through a scrubbing solution (usually a mixture of water and other compounds) allowing the particulate to attach to the liquid molecules. Electrostatic precipitators electrically charge the dirty air as it passes through. The now charged air then passes by large electromagnetic plates which attract the charged particle in the airstream collecting them and leaving the now clean air to be exhausted or recirculated.

Climate effects[edit]

2005 radiative forcings and uncertainties as estimated by the IPCC.

Atmospheric aerosols affect the climate of the earth by changing the amount of incoming solar radiation and outgoing terrestrial long wave radiation retained in the earth's system. This occurs through several distinct mechanisms which are split into direct, indirect[18][19] and semi-direct aerosol effects. The aerosol climate effects are the biggest source of uncertainty in future climate predictions.[20] The Intergovernmental Panel on Climate Change, Third Assessment Report, says: While the radiative forcing due to greenhouse gases may be determined to a reasonably high degree of accuracy... the uncertainties relating to aerosol radiative forcings remain large, and rely to a large extent on the estimates from global modelling studies that are difficult to verify at the present time.[21]

Aerosol radiative effects[edit]

Global aerosol optical thickness. The aerosol scale (yellow to dark reddish-brown) indicates the relative amount of particles that absorb sunlight.
These maps show average monthly aerosol amounts around the world based on observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite.

Direct effect[edit]

Particulates in the air causing shades of grey and pink in Mumbai during sunset

The Direct aerosol effect consists of any direct interaction of radiation with atmospheric aerosol, such as absorption or scattering. It affects both short and longwave radiation to produce a net negative radiative forcing.[22] The magnitude of the resultant radiative forcing due to the direct effect of an aerosol is dependent on the albedo of the underlying surface, as this affects the net amount of radiation absorbed or scattered to space. e.g. if a highly scattering aerosol is above a surface of low albedo it has a greater radiative forcing than if it was above a surface of high albedo. The converse is true of absorbing aerosol, with the greatest radiative forcing arising from a highly absorbing aerosol over a surface of high albedo.[18] The Direct aerosol effect is a first order effect and is therefore classified as a radiative forcing by the IPCC.[20] The interaction of an aerosol with radiation is quantified by the Single Scattering Albedo (SSA), the ratio of scattering alone to scattering plus absorption (extinction) of radiation by a particle. The SSA tends to unity if scattering dominates, with relatively little absorption, and decreases as absorption increases, becoming zero for infinite absorption. For example, sea-salt aerosol has an SSA of 1, as a sea-salt particle only scatters, whereas soot has an SSA of 0.23, showing that it is a major atmospheric aerosol absorber.

Indirect effect[edit]

The Indirect aerosol effect consists of any change to the earth's radiative budget due to the modification of clouds by atmospheric aerosols, and consists of several distinct effects. Cloud droplets form onto pre-existing aerosol particles, known as cloud condensation nuclei (CCN).

For any given meteorological conditions, an increase in CCN leads to an increase in the number of cloud droplets. This leads to more scattering of shortwave radiation i.e. an increase in the albedo of the cloud, known as the Cloud albedo effect, First indirect effect or Twomey effect.[19] Evidence supporting the cloud albedo effect has been observed from the effects of ship exhaust plumes[23] and biomass burning[24] on cloud albedo compared to ambient clouds. The Cloud albedo aerosol effect is a first order effect and therefore classified as a radiative forcing by the IPCC.[20]

An increase in cloud droplet number due to the introduction of aerosol acts to reduce the cloud droplet size, as the same amount of water is divided between more droplets. This has the effect of suppressing precipitation, increasing the cloud lifetime, known as the cloud lifetime aerosol effect, second indirect effect or Albrecht effect.[20] This has been observed as the suppression of drizzle in ship exhaust plume compared to ambient clouds,[25] and inhibited precipitation in biomass burning plumes.[26] This cloud lifetime effect is classified as a climate feedback (rather than a radiative forcing) by the IPCC due to the interdependence between it and the hydrological cycle.[20] However, it has previously been classified as a negative radiative forcing.[27]

Semi-direct effect[edit]

The Semi-direct effect concerns any radiative effect caused by absorbing atmospheric aerosol such as soot, apart from direct scattering and absorption, which is classified as the direct effect. It encompasses many individual mechanisms, and in general is more poorly defined and understood than the direct and indirect aerosol effects. For instance, if absorbing aerosols are present in a layer aloft in the atmosphere, they can heat surrounding air which inhibits the condensation of water vapour, resulting in less cloud formation.[28] Additionally, heating a layer of the atmosphere relative to the surface results in a more stable atmosphere due to the inhibition of atmospheric convection. This inhibits the convective uplift of moisture,[29] which in turn reduces cloud formation. The heating of the atmosphere aloft also leads to a cooling of the surface, resulting in less evaporation of surface water. The effects described here all lead to a reduction in cloud cover i.e. an increase in planetary albedo. The semi-direct effect classified as a climate feedback) by the IPCC due to the interdependence between it and the hydrological cycle.[20] However, it has previously been classified as a negative radiative forcing.[27]

Roles of different aerosol species[edit]

Sulfate aerosol[edit]

Sulfate aerosol has two main effects, direct and indirect. The direct effect, via albedo, is a cooling effect that slows the overall rate of global warming: the IPCC's best estimate of the radiative forcing is -0.4 watts per square meter with a range of -0.2 to -0.8 W/m² [30] but there are substantial uncertainties. The effect varies strongly geographically, with most cooling believed to be at and downwind of major industrial centres. Modern climate models addressing the attribution of recent climate change take into account sulfate forcing, which appears to account (at least partly) for the slight drop in global temperature in the middle of the 20th century. The indirect effect (via the aerosol acting as cloud condensation nuclei, CCN, and thereby modifying the cloud properties -albedo and lifetime-) is more uncertain but is believed to be a cooling.

Black carbon[edit]

Black carbon (BC), or carbon black, or elemental carbon (EC), often called soot, is composed of pure carbon clusters, skeleton balls and buckyballs, and is one of the most important absorbing aerosol species in the atmosphere. It should be distinguished from organic carbon (OC): clustered or aggregated organic molecules on their own or permeating an EC buckyball. BC from fossil fuels is estimated by the IPCC in the Fourth Assessment Report of the IPCC, 4AR, to contribute a global mean radiative forcing of +0.2 W/m² (was +0.1 W/m² in the Second Assessment Report of the IPCC, SAR), with a range +0.1 to +0.4 W/m². Bond et al., however, states that "the best estimate for the industrial-era (1750 to 2005) direct radiative forcing of atmospheric black carbon is +0.71 W/m² with 90% uncertainty bounds of (+0.08, +1.27) W/m²" with "total direct forcing by all black carbon sources, without subtracting the preindustrial background, is estimated as +0.88 (+0.17, +1.48) W/m²"[31]

Instances of aerosol affecting climate[edit]

Solar radiation reduction due to volcanic eruptions

Volcanoes are a large natural source of aerosol and have been linked to changes in the earth's climate often with consequences for the human population. Eruptions linked to changes in climate include the 1600 eruption of Huaynaputina which was linked to the Russian famine of 1601 - 1603,[32][33][34] leading to the deaths of two million, and the 1991 eruption of Mount Pinatubo which caused a global cooling of approximately 0.5 °C lasting several years.[35][36] Research tracking the effect of light-scattering aerosols in the stratosphere during 2000 and 2010 and comparing its pattern to volcanic activity show a close correlation. Simulations of the effect of anthropogenic particles showed little influence at present levels.[37][38]

Aerosols are also thought to affect weather and climate on a regional scale. The failure of the Indian Monsoon has been linked to the suppression of evaporation of water from the Indian Ocean due to the semi-direct effect of anthropogenic aerosol.[39]

Recent studies of the Sahel drought[40] and major increases since 1967 in rainfall over the Northern Territory, Kimberley, Pilbara and around the Nullarbor Plain have led some scientists to conclude that the aerosol haze over South and East Asia has been steadily shifting tropical rainfall in both hemispheres southward.[39][41]

The latest studies of severe rainfall declines over southern Australia since 1997[42] have led climatologists there to consider the possibility that these Asian aerosols have shifted not only tropical but also midlatitude systems southward.

Health effects[edit]

Air pollution measurement station in Emden, Germany

Size, shape and solubility matter[edit]

The size of the particle is a main determinant of where in the respiratory tract the particle will come to rest when inhaled. B Larger particles are generally filtered in the nose and throat via cilia and mucus, but particulate matter smaller than about 10 micrometers, referred to as PM10, can settle in the bronchi and lungs and cause health problems. The 10 micrometer size does not represent a strict boundary between respirable and non-respirable particles, but has been agreed upon for monitoring of airborne particulate matter by most regulatory agencies. Because of their small size, particles on the order of ~10 micrometers or less (PM10) can penetrate the deepest part of the lungs such as the bronchioles or alveoli.[43]

Similarly, so called fine PM, particles smaller than 2.5 micrometers, PM2.5, tend to penetrate into the gas exchange regions of the lung (alveolus), and very small particles (< 100 nanometers) may pass through the lungs to affect other organs. Penetration of particles is not wholly dependent on their size; shape and chemical composition also play a part. To avoid this complication, simple nomenclature is used to indicate the different degrees of relative penetration of a PM particle into the cardiovascular system. Inhalable particles penetrate no further than the bronchi as they are filtered out by the cilia. Thoracic particles can penetrate right into terminal bronchioles whereas PM which can penetrate to alveoli, the gas exchange area, and hence the circulatory system are termed respirable particles. In analogy, the inhalable dust fraction is the fraction of dust entering nose and mouth which may be deposited anywhere in the respiratory tract. The thoracic fraction is the fraction that enters the thorax and is deposited within the lung's airways. The respirable fraction is what is deposited in the gas exchange regions (alveoli).[44]

The smallest particles, less than 100 nanometers (nanoparticles), may be even more damaging to the cardiovascular system.[45] Nanoparticles can pass through cell membranes and migrate into other organs, including the brain. Particles emitted from modern diesel engines (commonly referred to as Diesel Particulate Matter, or DPM) are typically in the size range of 100 nanometers (0.1 micrometer). These soot particles also carry carcinogens like benzopyrenes adsorbed on their surface. Particulate mass is not a proper measure of the health hazard, because one particle of 10 µm diameter has approximately the same mass as 1 million particles of 100 nm diameter, but is much less hazardous, as it unlikely to enter the alveoli. Legislative limits for engine emissions based on mass are therefore not protective. Proposals for new regulations exist in some countries,[which?] with suggestions to limit the particle surface area or the particle count (numerical quantity) instead.[citation needed]

The site and extent of absorption of inhaled gases and vapors are determined by their solubility in water. Absorption is also dependent upon air flow rates and the partial pressure of the gases in the inspired air. The fate of a specific contaminant is dependent upon the form in which it exists (aerosol or particulate). Inhalation also depends upon the breathing rate of the subject.[46]

Another complexity not entirely documented is how the shape of PM can affect health, except for the needle-like shape of asbestos which can lodge itself in the lungs. Geometrically angular shapes have more surface area than rounder shapes, which in turn affects the binding capacity of the particle to other, possibly more dangerous substances.

Lung cancer, cardiovascular disease, respiratory diseases, premature delivery, birth defects, and premature death[edit]

The effects of inhaling particulate matter that have been widely studied in humans and animals include asthma, lung cancer, cardiovascular disease, respiratory diseases, premature delivery, birth defects, and premature death.

Increased levels of fine particles in the air as a result of anthropogenic particulate air pollution "is consistently and independently related to the most serious effects, including lung cancer[5] and other cardiopulmonary mortality."[47] The large number of deaths[48] and other health problems associated with particulate pollution was first demonstrated in the early 1970s[49] and has been reproduced many times since. PM pollution is estimated to cause 22,000-52,000 deaths per year in the United States (from 2000)[50] contributed to ~370,000 premature deaths in Europe during 2005.[51] and 3.22 million deaths globally in 2010 per the Global burden of disease collaboration.[52]

A 2002 study indicated that PM2.5 leads to high plaque deposits in arteries, causing vascular inflammation and atherosclerosis — a hardening of the arteries that reduces elasticity, which can lead to heart attacks and other cardiovascular problems.[53] A 2014 meta analysis reported that long term exposure to particulate matter is linked to coronary events. The study included 11 cohorts participating in the European Study of Cohorts for Air Pollution Effects (ESCAPE) with 100,166 participants, followed for an average of 11.5 years. An increase in estimated annual exposure to PM 2.5 of just 5 µg/m3 was linked with a 13% increased risk of heart attacks.[54]

The World Health Organization (WHO) estimated in 2005 that "... fine particulate air pollution (PM(2.5)), causes about 3% of mortality from cardiopulmonary disease, about 5% of mortality from cancer of the trachea, bronchus, and lung, and about 1% of mortality from acute respiratory infections in children under 5 years, worldwide.".[55] Short-term exposure at elevated concentrations can significantly contribute to heart disease. A 2011 study concluded that traffic exhaust is the single most serious preventable cause of heart attack in the general public, the cause of 7.4% of all attacks.[56]

The largest US study on acute health effects of coarse particle pollution between 2.5 and 10 micrometers in diameter. was published 2008 and found an association with hospital admissions for cardiovascular diseases but no evidence of an association with the number of hospital admissions for respiratory diseases.[57] After taking into account fine particle levels (PM 2.5 and less), the association with coarse particles remained but was no longer statistically significant, which means the effect is due to the subsection of fine particles.

Particulate matter studies in Bangkok Thailand from 2008 indicated a 1.9% increased risk of dying from cardiovascular disease, and 1.0% risk of all disease for every 10 micrograms per cubic meter. Levels averaged 65 in 1996, 68 in 2002, and 52 in 2004. Decreasing levels may be attributed to conversions of diesel to natural gas combustion as well as improved regulations.[58]

The Mongolian government agency recorded a 45% increase in the rate of respiratory illness in the past[when?] five years. Bronchial asthma, chronic obstructive pulmonary disease and interstitial pneumonia were the most common ailments treated by area hospitals. Levels of premature death, chronic bronchitis, and cardiovascular disease are increasing at a rapid rate.[14]

It has been suggested that particulate matter can cause similar brain damage as that found in Alzheimer patients.[citation needed]

Effects on vegetation[edit]

Particulate matter can clog stomatal openings of plants and interfere with photosynthesis functions.[59] In this manner high particulate matter concentrations in the atmosphere can lead to growth stunting or mortality in some plant species.

Regulation[edit]

Due to the highly toxic health effects of particulate matter, most governments have created regulations both for the emissions allowed from certain types of pollution sources (motor vehicles, industrial emissions etc.) and for the ambient concentration of particulates. The IARC and WHO designates particulates a Group 1 carcinogen. Particulates are the deadliest form of air pollution due to their ability to penetrate deep into the lungs and blood streams unfiltered, causing permanent DNA mutations, heart attacks and premature death.[4] In 2013, the ESCAPE study involving 312,944 people in nine European countries revealed that there was no safe level of particulates, and that for every increase of 10 μg/m3 in PM10, the lung cancer rate rose 22%. For PM2.5 there was a 36% increase in lung cancer per 10 μg/m3.[5] In a 2014 metaanalysis of 18 studies globally including the ESCAPE data, for every increase of 10 μg/m3 in PM2.5, the lung cancer rate rose 9%.[60]

Australia[edit]

Australia has set limits for particulates in the air:[61]

PM10 PM2.5
Yearly average None 8 µg/m3
Daily average (24-hour)

Allowed number of exceedences per year

50 µg/m3

None

25 µg/m3

None

Canada[edit]

In Canada the standard for particulate matter is set nationally by the federal-provincial Canadian Council of Ministers of the Environment (CCME). Jurisdictions (provinces) may set more stringent standards. The CCME standard for particulate matter 2.5 (PM2.5) is 30 μg/m3 (daily average, i.e. 24-hour period, 3 year average, 98th percentile).[62]

China[edit]

China has set limits for particulates in the air:[63]

PM10 PM2.5
Yearly average 70 µg/m3 35 µg/m3
Daily average (24-hour)

Allowed number of exceedences per year

150 µg/m3

None

75 µg/m3

None

European Union[edit]

The European Union has established the European emission standards which include limits for particulates in the air:[64]

PM10

since 1 January 2005

PM2.5¹

from 1 January 2015

Yearly average 40 µg/m3 25 µg/m3
Daily average (24-hour)

Allowed number of exceedences per year

50 µg/m3

35

None

None

¹ Target value entered into force 1.1.2010. Limit value enters into force 1.1.2015.

Hong Kong[edit]

Hong Kong has set limits for particulates in the air:[65]

PM10

Since 1 January 2014

PM2.5

Since 1 January 2014

Yearly average 50 µg/m3 35 µg/m3
Daily average (24-hour)

Allowed number of exceedences per year

100 µg/m3

9

75 µg/m3

9

Japan[edit]

Japan has set limits for particulates in the air:[66][67]

PM10[68] PM2.5

since 21 September 2009

Yearly average None 15 µg/m3
Daily average (24-hour)

Allowed number of exceedences per year

100 µg/m3 or 200 µg/m3[69]

None

35 µg/m3

None

South Korea[edit]

South Korea has set limits for particulates in the air:[70][71]

PM10

since 4 December 2006

PM2.5

from 1 January 2015

Yearly average 50 µg/m3 25 µg/m3
Daily average (24-hour)

Allowed number of exceedences per year

100 µg/m3

None

50 µg/m3

None

United States[edit]

The United States Environmental Protection Agency (EPA) has set standards for PM10 and PM2.5 concentrations.[72] (See National Ambient Air Quality Standards)

PM10

daily limit since 1987[73]
annual limit removed in 2006

PM2.5

daily limit since 2007
annual limit since 2012

Yearly average None 12 µg/m3
Daily average (24-hour)

Allowed number of exceedences per year

150 µg/m3

1

35 µg/m3

Not applicable (3 year average of annual 98th percentile)

California[edit]

In October 2008, the Department of Toxic Substances Control (DTSC), within the California Environmental Protection Agency, announced its intent to request information regarding analytical test methods, fate and transport in the environment, and other relevant information from manufacturers of carbon nanotubes.[74] DTSC is exercising its authority under the California Health and Safety Code, Chapter 699, sections 57018-57020.[75] These sections were added as a result of the adoption of Assembly Bill AB 289 (2006).[75] They are intended to make information on the fate and transport, detection and analysis, and other information on chemicals more available. The law places the responsibility to provide this information to the Department on those who manufacture or import the chemicals.

On January 22, 2009, a formal information request letter[76] was sent to manufacturers who produce or import carbon nanotubes in California, or who may export carbon nanotubes into the State.[77] This letter constitutes the first formal implementation of the authorities placed into statute by AB 289 and is directed to manufacturers of carbon nanotubes, both industry and academia within the State, and to manufacturers outside California who export carbon nanotubes to California. This request for information must be met by the manufacturers within one year. DTSC is waiting for the upcoming January 22, 2010 deadline for responses to the data call-in.

The California Nano Industry Network and DTSC hosted a full-day symposium on November 16, 2009 in Sacramento, CA. This symposium provided an opportunity to hear from nanotechnology industry experts and discuss future regulatory considerations in California.[78]

DTSC is expanding the Specific Chemical Information Call-in to members of the nanometal oxides, the latest information can be found on their website.[79]

Colorado[edit]

Key points in the Colorado Plan include reducing emission levels and solutions by sector. Agriculture, transportation, green electricity, and renewable energy research are the main concepts and goals in this plan. Political programs such as mandatory vehicle emissions testing and the prohibition of smoking indoors are actions taken by local government to create public awareness and participation in cleaner air. The location of Denver next to the Rocky Mountains and wide expanse of plains makes the metro area of Colorado's capital city a likely place for smog and visible air pollution.

Affected areas[edit]

U.S. counties violating national PM2.5 standards
U.S. counties violating national PM10 standards
Concentration of PM10[clarification needed] in Europe

The most concentrated particulate matter pollution tends to be in densely populated metropolitan areas in developing countries. The primary cause is the burning of fossil fuels by transportation and industrial sources.[citation needed]

Ulaanbaatar[edit]

Mongolia's capital city Ulaanbaatar, is affected by choking air pollution caused by coal and wood burning. The new market economy of the country and its very cold winter seasons have led to the formation of shantytowns (Ger districts), where 60% of the population of this, the coldest capital city in the world, reside. The poor in these districts cook and heat their wood houses with indoor stoves fueled by wood or coal. The resulting air pollution is characterized by raised sulphur dioxide and nitrogen oxide levels and very high concentrations of airborne particles and particulate matter (PM). Measurements carried out in Ulaanbaatar show that among the air pollution components, this dense PM has by far the most deadly health consequences.[14]

During the winter months in particular, urban air obscures vision, and negatively impacts human health. The air pollution also affects the visibility in the city to such an extent that airplanes on some occasions are prevented from landing at the local airport. The annual average temperature in Ulaanbaatar is 0 °C, making it the world's coldest capital city. About 40% of the population in Ulaanbaatar Mongolia lives in apartments, about 80% of them supplied with central heating systems from 3 combined heat and power plants (CHP). The power plants consumed almost 3.4 million tons of coal in 2007. The pollution control technology is in poor condition.

In addition to stack emissions, another unaccounted for source in the emission inventory is the fly ash from the ponds where fly ash is disposed. Removed fly ash is sent to settling tanks where the sedimented dust is collected and sent to the ash pond. These ash ponds are continually subjected to wind erosion in the dry season.

In Ulaanbaatar, Mongolia annual seasonal average particulate matter concentrations have been recorded as high as 279 µg/m3 (micrograms per cubic meter). To put this in perspective, the World Health Organization's recommended PM10 level is 20 µg/m3. This means that Ulaanbaatar's PM10 levels are 14 times higher than what is recommended. This also means that Ulaanbaatar has left Northern China's most polluted cities in its wake. Compared to such high concentrations, some cities in Northern China and South Asia also had concentrations above 200  µg/m3 up to a few years ago. The PM levels in Chinese cities are still extreme in recent years, reaching an all-time high in Beijing on Jan. 12, 2013, of 993 µg/m3.[14] To monitor the air quality of south China, the US Consulate Guangzhou set a PM 2.5 monitor on Shamian island in Guangzhou, Guangdong Province and showed data on the official website, social platforms like Twitter and Facebook and the consular application GZAir (Developed by FabriQate).[80]

See also[edit]

References[edit]

  1. ^ http://gmao.gsfc.nasa.gov/research/aerosol/modeling/nr1_movie/
  2. ^ http://gmao.gsfc.nasa.gov/research/aerosol/
  3. ^ Seinfeld, John; Spyros Pandis (1998). Atmospheric Chemistry and Physics: From Air Pollution to Climate Change (2nd ed.). Hoboken, New Jersey: John Wiley & Sons, Inc. p. 97. ISBN 0-471-17816-0. 
  4. ^ a b http://www.epa.gov/airquality/particulatematter/health.html
  5. ^ a b c Ole Raaschou-Nielsen et al. (July 10, 2013). "Air pollution and lung cancer incidence in 17 European cohorts: prospective analyses from the European Study of Cohorts for Air Pollution Effects (ESCAPE)". The Lancet Oncology. doi:10.1016/S1470-2045(13)70279-1. Retrieved July 10, 2013. "Particulate matter air pollution contributes to lung cancer incidence in Europe." 
  6. ^ Mary Hardin and Ralph Kahn. "Aerosols and Climate Change". 
  7. ^ "Primary and Secondary Sources of Aerosols: Soil dust". Climate Change 2001: Working Group 1. UNEP. 2001. 
  8. ^ "Nonequilibrium atmospheric secondary organic aerosol formation and growth". Proceedings of the National Academy of Sciences of the United States of America. Published online before print January 30, 2012. Bibcode:2012PNAS..109.2836P. doi:10.1073/pnas.1119909109. 
  9. ^ "Primary and Secondary Sources of Aerosols: Sea salt". Climate Change 2001: Working Group 1. UNEP. 2001. 
  10. ^ Int Panis, L.L.R. (2008). "The Effect of Changing Background Emissions on External Cost Estimates for Secondary Particulates". Open Environmental Sciences 2: 47–53. doi:10.2174/1876325100802010047. 
  11. ^ "Primary and Secondary Sources of Aerosols: Primary biogenic aerosols". Climate Change 2001: Working Group 1. UNEP. 2001. 
  12. ^ "Primary and Secondary Sources of Aerosols: Carbonaceous aerosols". Climate Change 2001: Working Group 1. UNEP. 2001. 
  13. ^ Felicity Barringer (February 18, 2012). "Scientists Find New Dangers in Tiny but Pervasive Particles in Air Pollution". The New York Times. Retrieved February 19, 2012. "Fine atmospheric particles — smaller than one-thirtieth of the diameter of a human hair — were identified more than 20 years ago as the most lethal of the widely dispersed air pollutants in the United States. Linked to both heart and lung disease, they kill an estimated 50,000 Americans each year." 
  14. ^ a b c d "Mongolia: Air Pollution in Ulaanbaatar - Initial Assessment of Current Situations and Effects of Abatement Measures". The World Bank. 2010. 
  15. ^ Click for more detail.
  16. ^ Click for more detail.
  17. ^ Dominick DalSanto. "The Encyclopedia of Dust Collection". 
  18. ^ a b Haywood, James; Boucher, Olivier (2000). "Estimates of the direct and indirect radiative forcing due to tropospheric aerosols: A review". Reviews of Geophysics 38 (4): 513. Bibcode:2000RvGeo..38..513H. doi:10.1029/1999RG000078. Retrieved August 11, 2012. 
  19. ^ a b Twomey, S. (1977). "The influence of pollution on the shortwave albedo of clouds". Journal of the Atmospheric Sciences 34 (7): 1149–1152. Bibcode:1977JAtS...34.1149T. doi:10.1175/1520-0469(1977)034<1149:TIOPOT>2.0.CO;2. 
  20. ^ a b c d e f Forster, Piers; Venkatachalam Ramaswamy; Paulo Artaxo; Terje Berntsen; Richard Betts; David W Fahey; James Haywood; et al. 2007. "Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change In Climate Change 2007: The Physical Science Basis,". In S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor, and H.L. Miller. Cambridge, United Kingdom and New York, NY, USA: Cambridge University Press. pp. 129–234. 
  21. ^ "6.7.8 Discussion of Uncertainties". IPCC Third Assessment Report - Climate Change 2001. Retrieved 14 July 2012. 
  22. ^ Charlson, R.J.; S E Schwartz; J M Hales; R D Cess; J A Coakley; J E Hansen; D J Hofmann (1992). "Climate forcing by anthropogenic aerosols". Science 255 (5043): 423–30. Bibcode:1992Sci...255..423C. doi:10.1126/science.255.5043.423. PMID 17842894. 
  23. ^ Ackerman, A S; Toon, O B; Taylor, J P; Johnson, D W; Hobbs, P V; Ferek, R J (1995). "Effects of Aerosols on Cloud Albedo : Evaluation of Twomey’s Parameterization of Cloud Susceptibility Using Measurements of Ship Tracks". Physics 57: 2684–2695. Bibcode:2000JAtS...57.2684A. doi:10.1175/1520-0469(2000)057<2684:EOAOCA>2.0.CO;2. 
  24. ^ Kaufman, Y. J.; Fraser, Robert S. (1997). "The Effect of Smoke Particles on Clouds and Climate Forcing.". Science 277 (5332): 1636–1639. doi:10.1126/science.277.5332.1636. .
  25. ^ Ferek, R J; Timothy Garrett; P V Hobbs; Scott Strader; Doug Johnson; J P Taylor; Kurt Nielsen; et al. (2000). "Drizzle Suppression in Ship Tracks". Journal of the Atmospheric Sciences 57 (16): 2707–2728. Bibcode:2000JAtS...57.2707F. doi:10.1175/1520-0469(2000)057<2707:DSIST>2.0.CO;2. 
  26. ^ Rosenfeld, D (1999). "TRMM observed first direct evidence of smoke from forest fires inhibiting rainfall". Geophysical Research Letters 26 (20): 3105–3108. Bibcode:1999GeoRL..26.3105R. doi:10.1029/1999GL006066. 
  27. ^ a b Hansen, J.; Sato, M.; Ruedy, R. (1997). "Radiative forcing and climate response". Journal of Geophysical Research 102 (D6): 6831–6864. Bibcode:1997JGR...102.6831H. doi:10.1029/96JD03436. 
  28. ^ Ackerman, A. S.; Toon, O. B.; Stevens, D. E.; Heymsfield, A. J.; Ramanathan v, V.; Welton, E. J. (2000). "Reduction of Tropical Cloudiness by Soot". Science 288 (5468): 1042–1047. doi:10.1126/science.288.5468.1042. PMID 10807573.  edit
  29. ^ Koren, I.; Kaufman, Y. J.; Remer, L. A.; Martins, J. V. (2004). "Measurement of the Effect of Amazon Smoke on Inhibition of Cloud Formation". Science 303 (5662): 1342–1345. doi:10.1126/science.1089424. PMID 14988557.  edit
  30. ^ "6.7.2 Sulphate Aerosol". IPCC Third Assessment Report, Working Group I: The Scientific Basis. IPPCC. 2001. Retrieved 10 August 2012. 
  31. ^ http://onlinelibrary.wiley.com/doi/10.1002/jgrd.50171/abstract
  32. ^ "1600 Eruption Caused Global Disruption", Geology Times, 25 Apr 2008, accessed 13 Nov 2010
  33. ^ Andrea Thompson, "Volcano in 1600 caused global disruption", MSNBC.com, 5 May 2008, accessed 13 Nov 2010
  34. ^ "The 1600 eruption of Huaynaputina in Peru caused global disruption", Science Centric
  35. ^ McCormick, M P; L W Thomason; C R Trepte (1995). "Atmospheric effects of the Mt Pinatubo eruption". Nature 373 (6513): 399–404. Bibcode:1995Natur.373..399M. doi:10.1038/373399a0. 
  36. ^ Stowe, L. L., R. M. Carey, and P. P. Pellegrino. 1992. “Monitoring the Mt. Pinatubo aerosol layer with NOAA/11 AVHRR data.” Geophysical Research Letters 19 (2): 159. doi:10.1029/91GL02958. http://www.agu.org/pubs/crossref/1992/91GL02958.shtml.
  37. ^ Sid Perkins (March 4, 2013). "Earth Not So Hot Thanks to Volcanoes". Science Now. Retrieved March 5, 2013. 
  38. ^ Neely, R. R. III; O. B. Toon, S. Solomon, J. P. Vernier, C. Alvarez, J. M. English, K. H. Rosenlof, M. J. Mills, C. G. Bardeen, J. S. Daniel, J. P. Thayer. "Recent anthropogenic increases in SO2 from Asia have minimal impact on stratospheric aerosol". Geophysical Research Letters (John Wiley & Sons, Ltd). Bibcode:2013GeoRL..40..999N. doi:10.1002/grl.50263. Retrieved March 5, 2013. "moderate volcanic eruptions, rather than anthropogenic influences, are the primary source of the observed increases in stratospheric aerosol." 
  39. ^ a b Chung, C E; Ramanathan, V (2006). "Weakening of North Indian SST Gradients and the Monsoon Rainfall in India and the Sahel". Journal of Climate 19 (10): 2036–2045. Bibcode:2006JCli...19.2036C. doi:10.1175/JCLI3820.1. 
  40. ^ Pollutants and Their Effect on the Water and Radiation Budgets
  41. ^ Australian rainfall and Asian aerosols
  42. ^ Pollution rearranging ocean currents
  43. ^ Region 4: Laboratory and Field Operations — PM 2.5 (2008).PM 2.5 Objectives and History. U.S. Environmental Protection Agency.
  44. ^ Nieuwenhuijsen, M.J. (2003). Exposure Assessment in Occupational and Environmental Epidemiology. London: Oxford University Press.
  45. ^ "Pollution Particles Lead to Higher Heart Attack Risk". Bloomberg L.P. 17 January 2008. 
  46. ^ Lippmann, M., Cohen, B.S., Schlesinger, R.S. (2003). Environmental Health Science. New York: Oxford University Press
  47. ^ "The global burden of disease due to outdoor air pollution". J. Toxicol. Environ. Health Part A 68 (13-14): 1301–7. 2005. doi:10.1080/15287390590936166. PMID 16024504. 
  48. ^ "Air Pollution & Cardiovascular Disease". National Institute of Environmental Health Sciences. 
  49. ^ Lave, Lester B.; Eugene P. Seskin (1973). "An Analysis of the Association Between U.S. Mortality and Air Pollution". Journal of the American Statistical Association 68: 342. doi:10.1080/01621459.1973.10482421. 
  50. ^ Mokdad, Ali H.; et al. (2004). "Actual Causes of Death in the United States, 2000". J. Amer. Med. Assoc. 291 (10): 1238–45. doi:10.1001/jama.291.10.1238. PMID 15010446. 
  51. ^ Spatial assessment of PM10 and ozone concentrations in Europe. 2005. doi:10.2800/165. 
  52. ^ Lim SS, Vos T, Flaxman AD, Danaei G, Shibuya K, Adair-Rohani H, (2012). "A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990–2010: a systematic analysis for the Global Burden of Disease Study 2010.". Lancet 380: :2224–2260. 
  53. ^ Pope, C Arden; et al. (2002). "Cancer, cardiopulmonary mortality, and long-term exposure to fine particulate air pollution". J. Amer. Med. Assoc. 287 (9): 1132–1141. doi:10.1001/jama.287.9.1132. PMID 11879110. 
  54. ^ EU's PM2.5 Limit Festering: New Study Linked PM with Heart Attack Cesaroni G, Forastiere F, Stafoggia M,; et al. (2014). "Long term exposure to ambient air pollution and incidence of acute coronary events: prospective cohort study and meta-analysis in 11 European cohorts from the ESCAPE Project.". BMJ (Clinical research ed.) 348. doi:10.1136/bmj.f7412. PMID 24452269. 
  55. ^ Aaron J. Cohen, H. Ross Anderson, Bart Ostro (2005). "The Global Burden of Disease Due to Outdoor Air Pollution". Journal of Toxicology and Environmental Health, Part A: 68, (13-14). doi:10.1080/15287390590936166. PMID 16024504. 
  56. ^ Nawrot, Tim S; Laura Perez; Nino Künzli; Elke Munters; Benoit Nemery (2011). "Public health importance of triggers of myocardial infarction: a comparative risk assessment". The Lancet 377 (9767): 732–740. doi:10.1016/S0140-6736(10)62296-9. ISSN 0140-6736.  "Taking into account the OR and the prevalences of exposure, the highest PAF was estimated for traffic exposure (7.4%)... " :"… [O]dds ratios and frequencies of each trigger were used to compute population-attributable fractions (PAFs), which estimate the proportion of cases that could be avoided if a risk factor were removed. PAFs depend not only on the risk factor strength at the individual level but also on its frequency in the community. ... [T]he exposure prevalence for triggers in the relevant control time window ranged from 0.04% for cocaine use to 100% for air pollution. ... Taking into account the OR and the prevalences of exposure, the highest PAF was estimated for traffic exposure (7.4%) ...
  57. ^ Newswise: National Study Examines Health Risks of Coarse Particle Pollution
  58. ^ Health Effects of Air Pollution in Bangkok
  59. ^ Hogan, C.Michael (2010). "Abiotic factor". In Emily Monosson and C. Cleveland. Encyclopedia of Earth. National Council for Science and the Environment. 
  60. ^ Ghassan B. Hamra,1 Neela Guha,1 Aaron Cohen et al (September 2014). "Outdoor Particulate Matter Exposure and Lung Cancer: A Systematic Review and Meta-Analysis". Environmental Health Perspectives 122 (9). doi:10.1289/ehp.1408092. Retrieved 2 September 2014. 
  61. ^ http://www.environment.gov.au/resource/national-standards-criteria-air-pollutants-1-australia
  62. ^ CANADA-WIDE STANDARDS for PARTICULATE MATTER (PM) and OZONE, Quebec City: Canadian Council of Ministers of the Environment, June 5–6, 2000 
  63. ^ http://kjs.mep.gov.cn/hjbhbz/bzwb/dqhjbh/dqhjzlbz/201203/W020120410330232398521.pdf
  64. ^ http://ec.europa.eu/environment/air/quality/standards.htm
  65. ^ "Air Quality Objectives". Environmental Protection Department, Hong Kong. 19 December 2012. Retrieved 27 July 2013. 
  66. ^ http://www.kankyo.metro.tokyo.jp/air/air_pollution/PM2.5/index.html
  67. ^ http://www2.dmu.dk/AtmosphericEnvironment/Expost/database/docs/AQ_limit_values.pdf
  68. ^ Referred to as Suspended Particulate Matter
  69. ^ 1 hour average limit
  70. ^ http://www.airkorea.or.kr/
  71. ^ http://cafe.naver.com/jjackhaps/595
  72. ^ http://www.epa.gov/ttn/naaqs/standards/pm/s_pm_history.html
  73. ^ http://www.epa.gov/airtrends/aqtrnd95/pm10.html
  74. ^ Nanotechnology web page. Department of Toxic Substances Control. 2008. 
  75. ^ a b Chemical Information Call-In web page. Department of Toxic Substances Control. 2008. 
  76. ^ Wong, Jeffrey (January 22, 2009), Call in letter 
  77. ^ "Contact List for CNT January 22 & 26 2009 Document". 
  78. ^ Archived DTSC Nanotechnology Symposia. Department of Toxic Substances Control. 
  79. ^ dtsc.ca.gov
  80. ^ http://guangzhou.usembassy-china.org.cn/guangzhou-air-quality-monitor.html

Further reading[edit]

External links[edit]