Journal of the Air & Waste Management Association (1995)
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J Air Waste Manag Assoc · Feb 2010
Comparative StudyA two-time-period comparison of the effects of ambient air pollution on outpatient visits for acute respiratory illnesses.
Concentrations of numerous ambient air pollutants have declined in recent years across the United States. Although it can be expected that reductions in air pollutants are associated with reductions in health effects, it is unclear whether this is actually the case. The purpose of this analysis was to compare the levels of and relationships between air pollutants and acute respiratory outpatient visits for two consecutive time periods totaling 53 mo. ⋯ Childhood asthma had the greatest number of significant associations with air pollutants, namely zinc and EC. The significant lag time between pollutant measurement and visit occurrence changed from 3-5 days in the first time period to 6-8 days in the later time period, but there was general consistency in several childhood asthma and pollutant associations over both time periods. The greatest evidence for a reduction in pollution being associated with an improvement in health response was for lower respiratory disease visits, but even in this case changes in other factors that influence health responses make it difficult to demonstrate that changes in pollutant levels influence health outcomes.
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J Air Waste Manag Assoc · Apr 2009
Air pollution and survival within the Washington University-EPRI veterans cohort: risks based on modeled estimates of ambient levels of hazardous and criteria air pollutants.
For this paper, we considered relationships between mortality, vehicular traffic density, and ambient levels of 12 hazardous air pollutants, elemental carbon (EC), oxides of nitrogen (NOx), sulfur dioxide (SO2), and sulfate (SO4(2-)). These pollutant species were selected as markers for specific types of emission sources, including vehicular traffic, coal combustion, smelters, and metal-working industries. Pollutant exposures were estimated using emissions inventories and atmospheric dispersion models. ⋯ However, we have not evaluated possible contributions from road dust or traffic noise. Stratification by traffic density level suggests the presence of response thresholds, especially for gaseous pollutants. Because of their wider distributions of estimated exposures, risk estimates based on emissions and atmospheric dispersion models tend to be more precise than those based on local ambient measurements.
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J Air Waste Manag Assoc · Jan 2009
The impact of background ozone on compliance with revised National Ambient Air Quality Standards.
The National Ambient Air Quality Standard (NAAQS) for ground-level ozone, previously set as an 8-hr average of 0.08 parts per million (ppm), has been revised by the U. S. Environmental Protection Agency (EPA). ⋯ Additionally, the highest observed background concentrations coincided with maximum photochemical generation at ground level. On the basis of the magnitude and variability of background ozone, a more stringent 8-hr ozone standard will be difficult for local or regional regulatory agencies to meet. A clear understanding of the impacts of background ozone will be required to make and meet new State Implementation Plans (SIPs).
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J Air Waste Manag Assoc · Jul 2008
Development of a field test method to evaluate gaseous air cleaner performance in a multizone building.
The performance of gaseous air cleaners for commercial and residential buildings has typically been evaluated using test protocols developed for a controlled laboratory chamber or a test duct. It is currently unknown how laboratory measurements relate to the actual performance of an air cleaner installed in a real building. However, to date, there are no air cleaner field test protocols available, thereby limiting the existing field data. ⋯ For each experiment, air cleaner removal of decane was directly measured using the air cleaner inlet and outlet concentrations, as well as with mass balance analyses using measured room concentrations. With a verified mass balance model, a field performance metric was developed to compare installed whole-building performance to the performance predicted by a laboratory result. The results provide insight into the protocols and metrics that might prove useful for characterizing the field performance of air cleaners as well as the impact of air cleaner removal on zonal concentration levels in a variety of situations.
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J Air Waste Manag Assoc · Jun 2005
Effect of liquefied petroleum gas on ozone formation in Guadalajara and Mexico City.
Leakages of liquefied petroleum gas (LPG) are suspected to contribute greatly to ozone (O3) formation in Mexico City. We tested such a hypothesis by outdoor captive-air irradiation (CAI) experiments in the two largest Mexican metropolitan areas: Guadalajara (GMA) in 1997 and Mexico City (MCMA) in 2000. O3 was monitored in each city for 20 days (8:00 a.m.-6:00 p.m.) in smog chambers containing unaltered morning air or morning air enriched with either commercial LPG or LPG synthetic mixture 60/40 (propane and butane). ⋯ Adding commercial LPG increased O3 (max) by 6% in GMA and 28% in MCMA; whereas adding LPG synthetic mixture 60/40 caused a similar increase in O3 (max), 4 and 21% in GMA and MCMA, respectively. Compared with dilution of tNMHCs, dilution of LPG-associated compounds had a smaller decreasing effect on O3 (max), only 4% in GMA and 15% in MCMA. These results show that commercial LPG and LPG synthetic mixture 60/40 affect O3 formation to a lesser extent than estimated previously.