Particulate Air Pollution In the United States

A study was conducted to identify, characterize, and quantify the national particulate air pollution problem from stationary sources. Particulate emissions from stationary sources were determined from data on emission factors, grain loadings, and material balances. The principal method used for establishing the tonnage emitted by an industry utilized uncontrolled emission factors. Total tonnage emitted by a given industry was calculated from four quantities: (1) an emission factor for the uncontrolled source; (2) the total tonnage processed per year by the industry; (3) the efficiency of control equipment used; and (4) the percentage of production capacity equipped with control devices.

Particulate emissions from stationary sources in the United States currently total approximately 18 X 10⁶ ton/yr. The major stationary sources of particulates include electric power generation plants, the crushed stone industry, the forest products industry, agriculture and related operations, the cement industry, and the iron and steel industry.

Three methods were developed to project the total quantity of particulate pollutants emitted up to the year 2000. In making these forecasts, these factors were considered (1) changes in production capacity; (2) improvements in control devices; and (3) regulatory action to enforce installation of control equipment.

These forecasts indicate that particulate emissions can be reduced from the current level of 18 X 10⁶ ton/yr to 3 X 10⁶ ton/yr by 2000 based on the most optimistic forecast. The projections also suggest that major reductions of particulate matter will most likely occur by installation of control equipment on uncontrolled sources and by shifts to more efficient types of collection equipment on existing controlled sources.     

Source Apportionment of Fine Particulate Matter in the Southeastern United States

Abstract

Particulate matter (PM) less than 2.5 μm in size (PM_2.5)source apportionment by chemical mass balance receptor modeling was performed to enhance regional characterization of source impacts in the southeastern United States. Secondary particles, such as NH₄HSO₄, (NH₄)₂SO₄,NH₄NO₃, and secondary organic carbon (OC) (SOC), formed by atmospheric photochemical reactions, contribute the majority (<50%) of ambient PM_2.5 with strong seasonality. Source apportionment results indicate that motor vehicle and biomass burning are the two main primary sources in the southeast, showing relatively more motor vehicle source impacts rather than biomass burning source impacts in populated urban areas and vice versa in less urbanized areas. Spatial distributions of primary source impacts show that each primary source has distinctively different spatial source impacts. Results also find impacts from shipping activities along the coast. Spatiotemporal correlations indicate that secondary particles are more regionally distributed, as are biomass burning and dust, whereas impacts of other primary sources are more local.     

Particulate nitrate measurements in rural areas of the western United States

As part of the Western Regional Air Quality Study (WRAQS), Teflon particle filters and Nylon backup filters were used to sample fine-particle nitrate and gaseous HNO₃ over the course of 1 year at rural sites in nine western states. Observed nitrate concentrations were generally low in the southern part of the network, even when allowances are made for possible losses of particulate nitrate in sampling and analysis. Particulate nitrate concentrations were substantially higher in the northern portion of the network, both in absolute terms and relative to sulfate concentrations. Measured HNO₃ concentrations, which were inflated over ambient levels by any volatilization of particulate nitrate during sampling, never exceeded 0.5 μg m⁻³ at the majority of sites. Occasional episodes of very high particulate nitrate concentrations were recorded; almost 15 % of the total particulate nitrate measured during the year was contributed by the five samples, out of the nearly 1500 analyzed, in which concentrations exceeded 1.5 μg m⁻³. These episodes manifested themselves not only in elevated nitrate concentrations, but in extinction coefficients and particulate mass concentrations which could not be accounted for by other measured chemical species.     

Particulate matter speciation profiles for light-duty gasoline vehicles in the United States

Representative profiles for particulate matter particles less than or equal to 2.5 µm (PM_2.5) are developed from the Kansas City Light-Duty Vehicle Emissions Study for use in the U.S. Environmental Protection Agency (EPA) vehicle emission model, the Motor Vehicle Emission Simulator (MOVES), and for inclusion in the EPA SPECIATE database for speciation profiles. The profiles are compatible with the inputs of current photochemical air quality models, including the Community Multiscale Air Quality Aerosol Module Version 6 (AE6). The composition of light-duty gasoline PM_2.5 emissions differs significantly between cold start and hot stabilized running emissions, and between older and newer vehicles, reflecting both impacts of aging/deterioration and changes in vehicle technology. Fleet-average PM_2.5 profiles are estimated for cold start and hot stabilized running emission processes. Fleet-average profiles are calculated to include emissions from deteriorated high-emitting vehicles that are expected to continue to contribute disproportionately to the fleet-wide PM_2.5 emissions into the future. The profiles are calculated using a weighted average of the PM_2.5 composition according to the contribution of PM_2.5 emissions from each class of vehicles in the on-road gasoline fleet in the Kansas City Metropolitan Statistical Area. The paper introduces methods to exclude insignificant measurements, correct for organic carbon positive artifact, and control for contamination from the testing infrastructure in developing speciation profiles. The uncertainty of the PM_2.5 species fraction in each profile is quantified using sampling survey analysis methods. The primary use of the profiles is to develop PM_2.5 emissions inventories for the United States, but the profiles may also be used in source apportionment, atmospheric modeling, and exposure assessment, and as a basis for light-duty gasoline emission profiles for countries with limited data.

Implications: PM_2.5 speciation profiles were developed from a large sample of light-duty gasoline vehicles tested in the Kansas City area. Separate PM_2.5 profiles represent cold start and hot stabilized running emission processes to distinguish important differences in chemical composition. Statistical analysis was used to construct profiles that represent PM_2.5 emissions from the U.S. vehicle fleet based on vehicles tested from the 2005 calendar year Kansas City metropolitan area. The profiles have been incorporated into the EPA MOVES emissions model, as well as the EPA SPECIATE database, to improve emission inventories and provide the PM_2.5 chemical characterization needed by CMAQv5.0 for atmospheric chemistry modeling.     

Particulate Sulfates in Pittsburgh Air

Atmospheric dustfall was qualitatively examined for sulfate content by the techniques of chemical micrurgy. Quantitative assessment of suspended sulfate particulate according to size was by cascade impactor sampling and turbidimetric analysis of stage washings as BaSO₄. Sulfate particles less than 1.9 micron mass median diameter in size contributed approximately 43% by weight and 90% by number to total particulate sulfate in Pittsburgh air. The mechanics of particulate sulfate formation in the atmosphere are discussed on the basis of these findings.     

Source Inventory IBM System for Particulate and Gaseous Pollutants

A source inventory IBM system of air pollutants is described which makes use of an existing IBM card index-registration system in an established air pollution control district and which employs efficient utilization of engineering time, including computer services, to establish and maintain current a detailed source inventory of point sources of emissions.     

The Regulation of Toxic Air Pollutants A Critical Review

ABSTRACT

Passage of the 1990 Clean Air Act Amendments launched the Acid Rain Program in the United States. This initiative, based on the market mechanism of a sulfur dioxide tradable “allowance” system, was a dramatic departure from traditional command and control strategies designed to reduce air pollution emissions. Power plant managers have flexibility under the program to select and implement a variety of options to reduce emissions below mandated levels. Federal agencies have collected annual performance data for affected facilities covered by the program for a number of years. Coal-burning plants are typically greater generators of sulfur dioxide (SO₂) than oil burners of equivalent size. This study examined the effect of fuel type as a significant factor influencing a plant's achievement in reducing pollution emissions. Achievement was measured by using a derived variable, delta (A), defined as the difference between pounds of SO₂ produced divided by the energy (in million Btu) generated, for the years 1990 and 1995. Rigorous nonparametric statistical analyses were used to compare the two populations of coal-fired and oil-fired plants. Results indicated that coal-burning facilities achieved greater program success, measured by the expected value of delta, than the oil combustors for the five-year period reviewed. Since utility managers must take steps to ensure all applicable requirements of the program are met, findings of the inquiry should prove to be useful in assessing achievable emissions reductions and aid in long-range facility planning.     

Visibility Measurements lo National Parks In the Western United States

Abstract

Existing quantitative standards/guidelines for fungi in indoor air issued by governmental agencies are based primarily on baseline data (rather than health effects data), and are either absolute (numerical) or relative (indoor/outdoor comparisons) or a combination of the two. The Russian Federation is the only governmental agency that has binding quantitative regulations for bioaerosols. Recommended guidelines have been proposed or sponsored by North American and European governmental agencies and private professional organizations. A considerable number of frequently cited guidelines have been proposed by individuals based either on baseline data or on personal experience. Quantitative standards/guidelines range from less than 100 CFU/ m3 to greater than 1000 CFU/m3 (total fungi) as the upper limit for non-contaminated indoor environments.

Major issues with existing quantitative standards and guidelines are the lack of connection to human dose/response data, reliance on short term grab samples analyzed only by culture, and the absence of standardized protocols for data collection, analysis, and interpretation. Urgent research needs include the study of human responses to specific fungal agents, development and widespread use of standard protocols using currently available sampling methodologies, and the development of long term, time-discriminating personal samplers that are inexpensive, easy to use, and amenable to straightforward, relevant analysis.     

Roadside Particulate Air Pollution in Bangkok

Abstract

Airborne fine particles of PM_2.5-10 and PM_2.5 in Bangkok, Nonthaburi, and Ayutthaya were measured from December 22, 1998, to March 26, 1999, and from November 30, 1999, to December 2, 1999. Almost all the PM₁₀ values in the high-polluted (H) area exceeded the Thailand National Ambient Air Quality Standards (NAAQS) of 120 μg/m³. The low-polluted (L) area showed low PM₁₀ (34–74 μg/m³ in the daytime and 54–89 μg/m³ at night). PM_2.5 in the H area varied between 82 and 143 μg/m³ in the daytime and between 45 and 146 μg/m³ at night. In the L area, PM_2.5 was quite low both day and night and varied between 24 and 54 μg/m³, lower than the U.S. Environmental Protection Agency (EPA) standard (65 μg/m³). The personal exposure results showed a significantly higher proportion of PM_2.5 to PM₁₀ in the H area than in the L area (H = 0.80 ± 0.08 and L = 0.65 ± 0.04).

Roadside PM₁₀ was measured simultaneously with the Thailand Pollution Control Department (PCD) monitoring station at the same site and at the intersections where police work. The result from dual simultaneous measurements of PM₁₀ showed a good correlation (correlation coefficient: r = 0.93); however, PM levels near the roadside at the intersections were higher than the concentrations at the monitoring station. The relationship between ambient PM level and actual personal exposures was examined. Correlation coefficients between the general ambient outdoors and personal exposure levels were 0.92 for both PM_2.5 and PM₁₀.

Bangkok air quality data for 1997–2000, including 24-hr average PM₁₀, NO₂, SO₂, and O₃ from eight PCD monitoring stations, were analyzed and validated. The annual arithmetic mean PM₁₀ of the PCD data at the roadside monitoring stations for the last 3 years decreased from 130 to 73 μg/m³, whereas the corresponding levels at the general monitoring stations decreased from 90 to 49 μg/m³. The proportion of days when the level of the 24-hr average PM₁₀ exceeded the NAAQS was between 13 and 26% at roadside stations. PCD data showed PM₁₀ was well correlated with NO₂ but not with SO₂, suggesting that automobile exhaust is the main source of the particulate air pollution. The results obtained from the simultaneous measurement of PM_2.5 and PM₁₀ indicate the potential environmental health hazard of fine particles. In conclusion, Bangkok traffic police were exposed to high levels of automobile-derived particulate air pollution.     

Outdoor-Indoor Levels of Six Air Pollutants

Comparisons were made of the levels of six air pollutants—total oxidant, per-oxyacetyl nitrate (PAN), nitric oxide, nitrogen dioxide, carbon monoxide, and particulate matter—outside and inside 11 buildings in the South Coast Basin of California during summer and fall.

Total oxidant levels inside depend upon how much outside air is being brought in and the residence time in the structure. With rapid intake and circulation, levels inside may be two-thirds those outside. With little intake and slow circulation, amounts inside decay to near zero. PAN is more persistent in buildings because it is more stable than ozone but also decays to low levels over an extended period. Oxides of nitrogen and CO are much more stable than oxidant or PAN and when carried into buildings remain until diluted or exhausted.

Particulate matter levels indoors depend largely upon velocity of air movement. Indoor areas where foot traffic was light or which had low ventilation rates had reduced amounts of particulate. Electrostatic precipitators were much more effective than coarse primary filters used in many buildings for removing particulate matter.     

Air Pollution Control Training in Colleges and Universities in the United States

A nationwide survey of air pollution control training efforts in the United States at colleges and universities was ccrried out for the S-l 1 Education and Training Committee, Air Pollution Control Association. Information from 91 schools having four year or graduate programs and five community colleges was received.Questions include type of course work, backgrounds of participating faculty and students, and eventual placement. At the present time about 70% of those in training are graduate students. It was found that most students taking initial employment in air pollution control activities had the M.S. degree. Recommendations for updating this information are made.     

Large-Scale Weather Influences on Community Air Pollution Potential in the United States

This paper describes the large-scale weather features that typically are associated with relatively rapid and slow atmospheric dispersion. Specific examples for some well-known air pollution incidents are illustrated and discussed. Particular attention is paid to the features of quasi-stagnating anticyclones, the typical weather system associated with persistent and extensive areas of sluggish dispersion. On the large scale, the basic quantitative parameters of dispersion over urban areas are the mixing height and the wind speed averaged through that height. These parameters are defined and discussed. Mean morning and afternoon mixing heights and wind speeds are presented for four locations across the United States, illustrating their diurnal, seasonal, and spatial variations. Also for these four locations, data are given on the climatological occurrence of periods during which critical values of the basic parameters were not exceeded. The spatial distributions of mixing heights and average wind speeds during a well-documented air pollution episode are presented.     

Arizona Hazardous Air Pollutants Monitoring Program

ABSTRACT

In order to evaluate the existing risk to public health in Arizona related to hazardous air pollution, ambient air monitoring for selected hazardous air pollutants (HAPs) was carried out in 1994-1996 in several representative urban and rural areas of Arizona. A wide range of organic HAPs was monitored, requiring a variety of sampling and analysis methods. Stainless steel SUMMA canisters were used for collection of volatile hydrocarbons and halocarbons, which were analyzed by capillary gas chromatography with flame ionization and electron capture detection (GC-FID/ECD). Carbonyl compounds were collected using 2,4-dinitrophenylhydrazine-impregnated cartridges and analyzed by high performance liquid chromatog-raphy with ultraviolet detection. Semi-volatile and non-volatile polycyclic aromatic compounds were collected using a sampling train consisting of a filter followed by a PUF/XAD-4/PUF sandwich cartridge. Following extraction, samples were analyzed by capillary GC with mass spectrometric detection (GC-MS). Database software was developed for data processing and reporting functions. This paper describes the sampling strategy and the sampling and analysis methods employed in the monitoring program and presents a summary of all the results obtained during the duration of the sampling program.     

Ozone and Other Air Quality-Related Variables Affecting Visibility in the Southeast United States

Abstract

An analysis of ozone (O₃) concentrations and several other air quality-related variables was performed to elucidate their relationship with visibility at five urban and semi-urban locations in the southeast United States during the summer seasons of 1980-1996. The role and impact of O₃ on aerosols was investigated to ascertain a relationship with visibility. Regional trend analysis over the 1980s reveals an increase in maximum O₃ concentration coupled with a decrease in visibility. However, a similar analysis for the 1990s shows a leveling-off of both O₃ and visibility; in both cases, the results were not statistically significant at the 5% level. A case study of site-specific trends at Nashville, TN, followed similar trends. To better understand the relationships between O₃ concentration and visibility, the analysis was varied from yearly through daily to hourly averaged values. This increased temporal resolution showed a statistically significant inverse relationship between visibility and O₃. Site-specific hourly r² values ranged from 0.02 to 0.43. Additionally, by performing back-trajectory analysis, it was found that the visibility degraded by air mass migration over polluted areas.