Showing papers on "Air quality index published in 1998"

Impact of temperature and humidity on the perception of indoor air quality

Abstract: Sensory responses to clean air and air polluted by five building materials under different combinations of temperature and humidity in the ranges 18-28°C and 30-70%RH were studied in the laboratory. A specially designed test system was built and a set of experiments was designed to observe separately the impact of temperature and humidity on the perception of air quality/odour intensity, and on the emission of pollutants from the materials. This paper reports on the impact on perception. The odour intensity of air did not change significantly with temperature and humidity; however, a strong and significant impact of temperature and humidity on the perception of air quality was found. The air was perceived as less acceptable with increasing temperature and humidity. This impact decreased with an increasing level of air pollution. Significant linear correlations were found between acceptability and enthalpy of the air at all pollution levels tested, and a linear model was established to describe the dependence of perceived air quality on temperature and humidity at different pollution levels.

Impact of Temperature and Humidity on Perception of Indoor Air Quality During Immediate and Longer Whole‐Body Exposures

Abstract: Acceptability of clean air and air polluted by building materials was studied in climate chambers with different levels of air temperature and humidity in the ranges 18–28°C and 30-70% relative humidity (RH). The acceptability of the air quality immediately after entering a chamber and during the following 20-min whole-body exposure was assessed by 36 untrained subjects who maintained thermal neutrality by modifying their clothing. The results confirm the significant decrement of the acceptability with increasing temperature and humidity, as shown in a previous study with facial exposures. The odour intensity was found to be independent of temperature and humidity. A linear relation between acceptability and enthalpy of air was again observed by this experiment. No significant difference was observed between the immediate acceptability and the acceptability during the following 20-min exposure, i.e., no adaptation took place. Both the immediate assessment of acceptability and the assessments during the 20-min exposure were independent of the air temperature and humidity to which the subjects were exposed before entering the chamber. The results further indicate that a notable decrement of the ventilation requirement may be achieved by maintaining a moderate enthalpy of air in spaces.

Organic molecular tracers for particulate air pollution sources

Abstract: The contribution of the major urban air pollution sources to regional particulate air quality problems can be diagnosed by using organic molecular marker techniques. Distinctive organic compounds or compound groups that are present in the emissions from some source types but not others are used to quantify the presence of the effluent from different air pollution sources within atmospheric fine particle samples. The tracer compounds are measured in source samples and in atmospheric samples by gas chromatography–mass spectrometry. Some of the most valuable tracers include hopanes and steranes from petroleum use in motor vehicles; phytosterols, lignans, phenolic products from lignins, and diterpenoids from resins in wood smoke; cholesterol in meat charbroiling smoke; high-molecular-weight odd carbon number n-alkanes in the particles shed as leaves rub together in the wind, and iso- and anteiso-alkanes in cigarette smoke. To date it has been demonstrated that the particles from up to nine different source types can be distinguished from each other simultaneously in the southern California atmosphere by this method. In the future, new analytical methods will increase the family of tracer compounds, assist in the identification of markers for additional sources, and speed the chemical analysis process in the laboratory.

Environmental Regulation and Productivity: Evidence from Oil Refineries

Abstract: We examine the effect of air quality regulation on the productivity of some of the most heavily regulated manufacturing plants in the United States, the oil refineries of the Los Angeles (South Coast) Air Basin. We use direct measures of local air pollution regulation in this region to estimate their effects on abatement investment. Refineries not subject to these local environmental regulations are used as a comparison group. We study the period of increased regulation between 1979 and 1992. On average each regulation cost $3M per plant on compliance dates and a further $5M per plant on dates of increased stringency. We also construct measures of total factor productivity using plant level data which allow us to observe physical quantities of inputs and outputs for the entire population of refineries. Despite the high costs associated with the local regulations, productivity in the Los Angeles Air Basin refineries rose sharply during the 1987 - 1992 period, a period of decreased refinery productivity in other regions. We conclude that measures of the cost of environmental regulation may be significantly overstated. The gross costs may be far greater than the net cost, as abatement may be productive.

On the Long‐Range transport of air pollutants from Europe to Africa

Abstract: The general climatic conditions and the physiographic characteristics of the area around the Mediterranean Sea, result in the formation of a flow pattern which is from North to South during all seasons and mainly during summer. This flow transports polluted air masses from southern Europe towards Africa. This transport is being investigated with the combined use of an atmospheric and a Lagrangian dispersion model. Air pollutants released from sources located in southern Europe were found in the entire tropospheric region over North Africa. The time scales for such a transport were found to be four to six days. This kind of transport can have several implications ranging from degradation of the air quality in North African cities to the water budget and regional climatic change.

Sources and Control of Air Pollution

Abstract: sources and control of air pollution studiokdev sources and control of air pollution klmvc sources and control of volatile organic air pollutants air pollution control epa air pollution engineering welcome to caltechauthors sources and control of air pollution snowlog water pollution: sources, effects, control and management state air pollution control board regulations for the technologies for air pollution control eolss point sources of pollution: local effects and control air pollution control at construction sites air pollution control regulations vermont air pollution: causes, sources and abatement ce 476/576. air pollution control fact sheet: air pollution emission control devices for outdoor air pollution who air pollution control rules and regulations sources, types and distribution of air cffet air pollution and its sources soma medical air pollution control officer placer ridem/air resources-air pollution control regulation no. 9 clean air act epa archives tuolumne county air pollution control district air pollution control dnr general regulations for air pollution sources does my business need an air pollution control permit? air pollution control regulations vermont air pollution control technology fact sheet us epa air pollution in china: mapping of concentrations and sources solution to control air pollution expoll air pollution control us epa indian journal of air pollution control harboring pollution nrdc ridem/air resources-air pollution control regulation no. 28 chapter 5 . sources of air pollution: gasoline and diesel using bioreactors to control air pollution air pollution control in china: progress and perspectives air quality in minnesota * minnesota pollution control taking control of air pollution in mexico city idrc appendix a controlling sources of toxic air pollutants mobile source air pollution control program archives air pollution and control facsys regulations for the control and abatement of air pollution air pollution uc berkeley college of natural resources air pollution control rules michigan air pollution control district imperial county website chapter 3 source control of pollution air pollution in china washington state university pollution control minnesota determining sources of environmental pollution

Population growth and air quality in California.

Abstract: Demographers are often interested in the environmental impacts of population growth. I examine the impact of growth specifically on air quality in California. In recent decades, California has suffered from notoriously polluted air and has experienced rapid population growth. Despite the population .growth, air quality actually has improved since the early 1980s due to aggressive regulatory efforts. Using data for 56 counties, I analyze the contribution of population growth to trends in atmospheric emissions of five regulated pollutants from 1980 to 1990, controlling for trends in per capita income and regulatory efforts. The analysis is disaggregated by source of emissions and demonstrates that population growth is strongly associated with some sources of emissions but not with others. Thus, the overall impact of population growth depends upon the composition of production and consumption activities in each county. I also explore whether the trend in number of households predicts better than the trend in number of persons, and whether the impact of population growth depends upon the age structure or source of growth (immigration or domestic increase). Generally, these alternative specifications of population do not improve the models of atmospheric emissions.

Indoor climate and air quality. Review of current and future topics in the field of ISB study group 10.

Abstract: In industrialized countries about 90% of the time is spent indoors. The ambient parameters affecting indoor thermal comfort are air temperature and humidity, air velocity, and radiant heat exchange within an enclosure. In assessing the thermal environment, one needs to consider all ambient parameters, the insulating properties of the occupants' clothing, and the activity level of the occupants by means of heat balance models of the human body. Apart from thermal parameters, air quality (measured and perceived) is also of importance for well-being and health in indoor environments. Pollutant levels are influenced by both outdoor concentrations and by indoor emissions. Indoor levels can thus be lower (e.g. in the case of ozone and SO2) or higher (e.g. for CO2 and formaldehyde) than outdoor levels. Emissions from cooking play an important role, especially in developing countries. The humidity of the ambient air has a wide range of effects on the energy and water balance of the body as well as on elasticity, air quality perception, build-up of electrostatic charge and the formation or mould. However, its effect on the indoor climate is often overestimated. While air-handling systems are commonly used for achieving comfortable indoor climates, their use has also been linked to a variety of problems, some of which have received attention within the context of "sick building syndrome".

Modeling the Effects of Urban Vegetation on Air Pollution

Abstract: Urban vegetation can directly and indirectly affect local and regional air quality by altering the urban atmospheric environment. Trees affect local air temperature by transpiring water through their leaves, by blocking solar radiation (tree shade), which reduces radiation absorption and heat storage by various anthropogenic surfaces (e. g., buildings, roads), and by altering wind characteristics that affect air dispersion. During the summertime, trees predominantly reduce local air temperatures, but may increase within- and below-canopy air temperature due to reduced turbulent exchange with above-canopy air (Heisler et al., 1995). Reduced air temperature due to trees can improve air quality because the emission of many pollutants and/or precursor chemicals are temperature dependent. Decreased air temperature can also reduce ozone (O3) formation (Cardelino and Chameides, 1990).

Does Air Quality Matter? Evidence from the Housing Market

Abstract: This study exploits the quasi-random assignment of air pollution changes across counties induced by federally mandated air pollution regulations to identify the impact of particulate matter on property values. Two striking empirical regularities emerge from the analysis. First particulate matter declined substantially more in regulated than in unregulated counties during the 1970s and 1980s. At the same time, housing prices rose more in regulated counties. The evidence suggests that this approach identifies two causal effects: 1) the impact of regulation on air quality improvements, and 2) the impact of regulation on economic gains for home-owners. In addition, the results highlight the importance of choosing regulatory instruments that are orthogonal to unobserved housing price shocks that vary by county over long time horizons. It appears that using regulation-induced changes in particulate matter leads to more reliable estimates of the capitalization of air quality into property values. Whereas the conventional cross-sectional and unstable and indeterminate across specifications, the instrumental variables estimates are much larger, insensitive to specification of the model, and appear to purge the biases in the conventional estimates. The estimates imply that a one-unit reduction in suspended particulates results in a 0.7-1.5 percent increase in home values. In addition, it appears that air pollution regulations resulted in real economic benefits to home-owners in regulated counties.

Association between hospital emergency visits for asthma and air pollution in Valencia, Spain.

Abstract: OBJECTIVE: To assess the short term effect of concentrations of black smoke, sulphur dioxide (SO2), nitrogen dioxide (NO2) and ozone (O3) in ambient air on emergency room visits for asthma in the city of Valencia, Spain during the period 1994-5. METHODS: Ecological study with time series data and application of Poisson regression. Associations between number of daily emergency visits in a city's hospital and concentrations of air pollutants were analysed taking into account potential confounding factors by the standardised protocol of the air pollution and health: a European approach (APHEA) project. RESULTS: Mean (range) daily number of emergency room visits for asthma was 1 (0-5). Concentrations of all pollutants studied remained within current air quality standards. The association between an increase of 10 micrograms/m3 in ambient air pollution and asthma, measured as a relative risk (RR) of emergency visits, was significant for NO2 24 hour mean (lag 0, RR 1.076, 95% confidence interval (95% CI) 1.020 to 1.134), NO2 hour maximum (lag 0, RR 1.037, 95% CI 1.008 to 1.066), and O3 hour maximum (lag 1, RR 1.063, CI 95% 1.014 to 1.114). The association was not significant for SO2 or for black smoke during the period analysed. The effects were not significantly different for the time of year, cold months (November to April), or warm months (May to October). CONCLUSIONS: Current concentrations of ambient air pollution in Valencia are significantly associated with emergency room visits for asthma. This association is high and more consistent for NO2 and O3 than for particulate matter and SO2 (classic pollutants).

Northern Front Range Air Quality Study Final Report Volume B: Source Measurements

Abstract: Over 100 radiocarbon (C) analyses of both ambient PM2.5 (particulate matter with an aerodynamic diameter of 2.5 μm or less) and PM2.5 source samples from the Northern Front Range Air Quality Study (NFRAQS) were performed. These analyses were designed to address, in part, two specific objectives of the summer and winter portions of the study, viz... Objective 3 of the summer study: “to provide information for comparison with the data collected at the winter 1996 core monitoring site at Welby and the major study during the fall and winter of 1996-1997” and Objective 1 of the winter study: “source apportionment of carbonaceous material in airborne particles in the NFRAQS study region”. The unique value of C analysis in source apportionment studies such as this is that it by definition apportions the modern and fossil components of atmospheric aerosol carbon or carbon sub-fractions. Results of these analyses will be used as a quality control check on the carbon apportionments generated by the Chemical Mass Balance (CMB) receptor model. Samples were prepared as Fe-C bead targets for analysis of C by accelerator mass spectrometry (AMS). This type of analysis has proven to be reliable in atmospheric aerosol source apportionment studies for samples that may contain as little as 20-100 μg C (e.g., Currie et al, 1986, Klouda et al., 1987, Klinedinst et al., 1993, Hildemann et al., 1994). The AMS C analysis of the NFRAQS samples yielded relative measurement uncertainties (1σ Poisson counting statistics) of 2%-3%. Consistent with past experience, applying a blank correction to the C measurements, fM (Corr.), inflated the uncertainty, in some cases dramatically. The majority of the ambient samples analyzed for C were from the Welby and Brighton core sites. These samples consisted of sixteen corresponding (same date and time) winter samples from Welby and Brighton and twenty-two Welby summer samples. For the sampling days and periods represented in this study, the median and range of the winter fM (Corr.) data at Welby was 0.23 (0.16-0.34), and at Brighton 0.27 (0.25-0.37) or equivalently 77% and 73% fossil carbon. Welby summer samples also exhibited a predominantly fossil carbon fM (Corr.) signature, 0.47 (0.09-0.70), but with a much broader range. Source samples analyzed for C consisted of particulate emissions from heavy and light duty vehicles, wood smoke, meat cooking, synthetic logs and road dust. Results were consistent with expectations; motor vehicle emissions were close to 100% fossil carbon; wood smoke and meat cooking close to 100% modern carbon. The synthetic logs had a mixed source signature, fM (Corr.) of 0.20. Road dust samples exhibited modern carbon results ranging from 60% to 220% indicating potential C contamination of some of the samples and demonstrating the ambiguous nature of this source category.

Ozone formation and transport in southeastern United States: Overview of the SOS Nashville/Middle Tennessee Ozone Study

Abstract: The Southern Oxidants Study (SOS) is a public-private partnership collectively engaged, since 1989, in a coordinated program of policy-relevant research to improve scientific and public understanding of tropospheric ozone pollution. In the summers of 1994 and 1995, SOS implemented the Nashville/Middle Tennessee Ozone Study. This effort, the second SOS urban intensive study, conducted a series of integrated, process-oriented airborne and surface measurement experiments to better understand the chemistry and meteorology associated with the production, transport, and impact of tropospheric ozone. Specific technical objectives addressed (1) the role of biogenic VOC and NOx emissions on local and regional ozone production, (2) the effect of urban-rural exchange/interchange on local and regional ozone production, (3) sub-grid-scale photochemical and meteorological processes, and (4) the provision of a high-quality chemical and meteorological data set to test and improve observation- and emission-based air quality forecast models. Some of the more significant findings of the 1994–1995 studies include the following: (1) Ozone production in Nashville was found to be close to the transition between NOx-sensitive and VOC-sensitive chemistry. (2) Ozone production efficiency (OPE) in power plant plumes, molecules of ozone formed per molecule of NOx emitted, was found to be inversely proportion to NOx emission rate, with the plants having the greatest NOx emissions exhibiting the lowest OPE. (3) During stagnant conditions, nighttime winds dominated pollutant transport and represent the major mechanism for transporting urban pollutants to rural areas. Ultimately, results provided by this research will allow improved assessment of existing ozone management strategies and provide better scientific tools for the development of future management strategies.

Rollably positioned, adjustably directable clean air delivery supply assembly, for use in weather protected environments to provide localized clean air, where activities require clean air quality per strict specifications

Abstract: An adjustably directable clean air delivery supply assembly which provides clean air for use in weather protected environments. This assembly is, doorway passable and rollably positioned, to be utilized where activities require very clean air per strict specifications. When located, the device can quickly be unfolded and positioned for operation to produce clean air in the desired direction at minimal-eddy producing airflow. Surrounding unfiltered air is drawn in just above floor level through a pre-filter into a airtight lower hollow housing, which contains an interior powered air moving assembly, and discharged upwardly into the tower hollow housing which is supported on top of the lower hollow housing. Secured to the tower hollow housing is an adjustable telescoping height and rotatable positioning structural tube, which receives and directs the air upwardly through a self-sealing bellows into the top final filter hood assembly. The bellows encapsulates a fully adjustable, interconnecting, angularly adjustable, positioning hinge. The pre-filtered air then passes through a final filter such as a high efficiency particle arrestor type air filter. The final filtered air then is discharged in a desired direction at a selected volume into a shrouded or unshrouded area. The top final filter hood assembly is movable through one hundred eighty degrees of vertical arc, horizontally rotatable, and can be raised or lowered for operation, or folded against the lower hollow housing for storage. This self-contained clean air supply assembly can be transported, adjusted, and reused without recertification testing, when it is handled and operated properly.

Vehicle air conditioning monitoring device

Abstract: A device for use in vehicles with electric or hybrid drive for monitoring the air conditioning of a vehicle based on health and energy consumption readings. The device monitors the operation of the air conditioning to determine when differentials between outside and inside temperature are excessive, and/or inside atmospheric humidity is too low and/or air quality is poor. An occurrence of any of these conditions results in the system suggesting to the driver that he should interrupt travel to the desired destination. In addition, if necessary, the device performs a vehicle range estimate as a function of the selected air conditioning operation.