Evaluation of radon mitigation systems in 14 houses over a two-year period

Fourteen single-family detached houses in Spokane, Washington, and Coeur D'Alene, Idaho, were monitored for two years after high concentrations of indoor radon had been mitigated. Each house was monitored quarterly using mailed alpha-track radon detectors deployed in each zone of the structure. To assess performance of mitigation systems during the second heating season after mitigation, radon concentrations in seven houses were monitored continuously for several weeks, mitigation systems in all houses were inspected, and selected other measurements were taken. In addition, occupants were also interviewed regarding their maintenance, operation, and subjective evaluation of the radon mitigation systems. Quarterly alpha-track measurements showed that radon levels had increased in most of the homes during many follow-up measurement periods when compared with concentrations measured immediately after mitigation. Mitigation-system performance was adversely affected by (1) accumulated outdoor debris blocking the outlets of subsurface pressurization pipes; (2) fans being turned off (e.g., because of excessive noise or vibration); (3) air-to-air heat exchanger, basement pressurization, and subsurface ventilation fans being turned off and fan speeds reduced; and (4) crawl-space vents being closed or sealed.     

Evaluation of Radon Mitigation Systems in 14 Houses Over a Two-year Period

Fourteen single-family detached houses In Spokane, Washington, and Coeur D’Alene, Idaho, were monitored for two years after high concentrations of indoor radon had been mitigated. Each house was monitored quarterly using mailed alpha-track radon detectors deployed in each zone of the structure. To assess performance of mitigation systems during the second heating season after mitigation, radon concentrations in seven houses were monitored continuously for several weeks, mitigation systems In all houses were inspected, and selected other measurements were taken. In addition, occupants were also interviewed regarding their maintenance, operation, and subjective evaluation of the radon mitigation systems. Quarterly alpha-track measurements showed that radon levels had increased In most of the homes during many follow-up measurement periods when compared with concentrations measured immediately after mitigation. Mitigation-system performance was adversely affected by (1) accumulated outdoor debris blocking the outlets of subsurface pressurization pipes; (2) fans being turned off (e.g., because of excessive noise or vibration); (3) air-to-air heat exchanger, basement pressurization, and subsurface ventilation fans being turned off and fan speeds reduced; and (4) crawlspace vents being closed or sealed.     

Performance of Exhaust Control Devices on 1966 Model Passenger Cars

Road tests have been carried out in five different cities with a fleet of 300 passenger cars consisting of three different makes, half of which are equipped with the 1966 exhaust control devices required by the state of California. The performance of these devices during the first series of tests has been evaluated. All three makes of device-equipped cars produced significantly lower emissions of hydrocarbons and carbon monoxide than did similar cars tested in 1962 and 1963. There were no consistent differences among the three makes of cars with respect to carbon monoxide and hydrocarbon emissions.     

Exposure of Drivers to Carbon Monoxide

Eleven new cars were driven around a 35 km route comprising heavily trafficked roads in and around London, and the concentrations of carbon monoxide inside and immediately outside the vehicles were continuously monitored. Average levels of CO between 12 and 60 parts per million were found inside the cars, and these levels were between 30 and 80% of the external concentrations. The internal levels varied according to external changes but the changes were greatly damped by the buffering effect of the ventilation system. Differences in internal CO levels were more marked between vehicles than for different runs in the same vehicle and were probably due to differences in the ventilation systems.

Blood carboxy-hemoglobin concentrations which would arise from the CO exposures were calculated. Published data suggest that carboxy-hemoglobin concentrations within the range found (1.5-3.0%) would not be expected to produce an adverse effect on health; there are conflicting views as to whether driving performance would be impaired.     

Composition,Size and Control of Automotive Exhaust Particulates

This paper on automobile exhaust particulates describes total particulate composition, size of exhausted lead particulates, and the effects of traps on total lead emitted. This study was conducted using cars manufactured during 1966-1970. Work in suspended particulate emission from several vehicles operated on a chassis dynamometer under Federal 7-mode cycle conditions has shown: (1 ) cars vary widely in the amounts and composition of their particulate emissions; (2) cold-cycle operation gives 2-8 times more particulate than hot engine operation; (3) lead compounds represent less than one-third of total particulates, the remainder being carbon compounds along with ammonium and nitrate ions and unknown materials; (4) carbon emission for stabilized cars using leaded gasoline varies widely but averages about 35% of the total; (5) suspended particulate emissions are nearly equal with new cars whether or not lead is present; (6) exhausted lead varies with the condition of the exhaust system and ranges between 7 and 30% of the lead consumed by the engine; (7) fuel additives affect the amount of emitted particulates; (8) probe sampling techniques underestimate by a large factor the amount of particulates emitted by vehicles; and (9) trapping systems offer potential for greatly reducing the emission of suspended total particulates.     

Comparison of Air Pollutant Emissions from Vaporizing and Air Atomizing Waste Oil Heaters

Information presented in this paper is directed to individuals concerned with emissions from combustion of waste crankcase oil for space heating. Studies were performed to characterize gaseous and particulate emissions and vaporizing pot solid residues resulting from the combustion of waste crankcase oil. Two types of waste oil burners were tested. One was a vaporizing oil burner rated at 35.2 kW (120,000 Btu/h heat input), and the other was an air atomizing oil burner rated at 73.3 kW (250,000 Btu/h heat input). Except for NO_X and SO_X, gaseous emissions were similar to those from conventional distillate oil combustion. NO_X and SO_X emissions were higher due to higher fuel nitrogen and sulfur concentrations. Waste oil from automotive use showed higher inorganic levels than crankcase oil used for truck engine lubrication. Both burner types discharged high levels of metallic species, but the air atomizing unit had much higher stack emission levels than did the vaporizing pot system. Also, particulate loading levels were an order of magnitude higher for the air atomizing burner than for the vaporizing pot burner when firing the waste oils. However, the vaporizing pot burner generated a waste residue containing the majority of its elemental emissions. Elements which exceeded threshold limit values for one or both heaters were cadmium, chromium, cobalt, copper, iron, lead, nickel, phosphorus, and zinc. However, the nickel and much of chromium appeared to be a sampling artifact caused by the stainless steel sampling system.     

Long-term efficiency of catalytic converters operating in Mexico City

A 1999 ordinance by the Government of Mexico City bans 1993 model-year vehicles from on-road operation if their catalytic converters are not replaced with new ones. To validate the benefits of this action, we examined three issues related to exhaust emissions of vehicles equipped with catalytic converters. After selecting representative fleets of in-use vehicles, a comparison between emissions and catalyst efficiency in cars with two categories of exhaust emission limits was carried out. For that purpose, two fleets were selected, each made up of 10 vehicles run under similar conditions. A third, larger fleet with emissions control systems was used to evaluate and simulate real-world conditions of vehicles in a controlled laboratory. Finally, the aging effect on the catalytic converter was studied on vehicles run for 100,000 km, replacing their old emission control devices for new ones. The 1991-1992 model-year vehicles showed a high percentage of compliance with the corresponding emissions standard (90%) in comparison with 1993 model-year and later vehicles (Tier 0). However, NOx emissions were higher for the newer vehicles. Fifty percent of the 1991-1992 model-year vehicles evaluated under the official inspection/maintenance (I/M) procedure did not meet the regulated emissions standard when the results were compared with those of the U.S. Federal Test Procedure FTP-75. Our results suggest that the replacement of old catalytic converters with new ones will have little effect on decreasing polluting emissions because these vehicles were in very bad mechanical condition. Results of catalytic activity as a function of mileage indicated inefficient catalyst performance for the fleets tested. All pollutant conversions were below 90% efficiency, and they deteriorated by an average of 30% after the vehicles were run for 100,000 km.     

New Jersey Repair Project: Tune-Up at Idle

Idle hydrocarbon and carbon monoxide measurements have been made on over 2500 cars at a New Jersey Inspection Station. These studies have shown that the idle test can be integrated into the present periodic motor vehicle inspection system with a minimum cost, testing time, and ease of operation.

Instrumentation at a low cost has recently become available, test procedures have been developed and potential emission reductions have been demonstrated for idle testing. High emissions indicate a car malfunction and the need for a tune-up. Effective low cost tune-ups can be made with exhaust instrumentation and garage training.

In the New Jersey REPAIR Project, preliminary idle cut-off levels were selected at 6% carbon monoxide and 1000 ppm hydrocarbon for pre-68 cars, 4% and 500 ppm for 1968–69 cars, and 3% and 300 ppm for later years. Volunteered vehicles which exceeded these levels were further tested at the New Jersey laboratory. Federal hot cycles, ACID mass cycles, Key Mode, and Idle tests were conducted before and after maintenance.

At idle, uncontrolled pre-1968 vehicles had an average reduction from 8.2 to 3.3% carbon monoxide and 2153 to 459 ppm hydrocarbons as hexane. Average mass reductions from the ACID-cycle were 45 g/mi CO and 6.3 g/mi hydrocarbons. Carbon monoxide idle reductions obtained for emission controlled 1968, 1969, and 1970 cars were about equal to those obtained for the pre-emission controlled vehicles, but hydrocarbon reductions were lower. Reductions obtained in federal hot cycles were from 4.1 to 2.1% CO and 1418 to 580 ppm hydrocarbons for pre-1968 cars, and 2.6 to 0.7% and 502 to 308 ppm for 1968–1969 cars.

Idle adjustments lower emissions in the idle, deceleration, and cruise modes up to 30 mph, thus urban driving areas should show the greatest reduction. Total motor vehicle emission reduction in New Jersey would be about 920,000 ton/yr of CO and 101,000 ton/yr of hydrocarbon; a 20 and 32% reduction.     

An Analysis of Michigan and California CO Remote Sensing Measurements

Abstract

Remote sensing measurements of CO emissions from on-road vehicles were made in California in 1991 and in Michigan in 1992. It was determined that both fleets had a small linear increase in the high emitter frequency (vehicles emitting more than 4% CO) as a function of vehicle age for 1986 and newer model vehicles. Although high emitting vehicles were only a small minority of the fleet, they had a dominant impact on the mean CO and total CO emitted by the fleet. In Michigan, the highest emitting 5% of passenger cars generated 45% of the CO from cars. In California, the highest emitting 5% of passenger cars generated 38% of the CO from cars. There was a high correlation between the mean CO emitted by each model year of vehicle and the frequency of high emitting vehicles within the model year for both the Michigan and California fleets. The frequency of high emitters within any model year had no obvious relation to that model year’s certification standards. The high emitter frequencies for vehicles less than nine years old were very similar for the California and Michigan fleets. An increase in the high emitter frequency in the ten-year-old and older Michigan passenger car fleet (relative to the California passenger car fleet), suggests, but does not conclusively demonstrate, that the rate of high emitters in Michigan and California is reduced by the inspection and maintenance (I/M) programs.     

California Vehicle Exhaust Control

The purpose of this paper is to relate California’s experience with vehicle exhaust controls for three model years and to discuss future possibilities for improving the continued effectiveness of these controls. Tests of exhaust controls on 1966 and subsequent model cars in public use indicate a reduction in hydrocarbons of about 60% for the vehicle life of 100,000 miles compared to uncontrolled cars. However, emission levels and emission deterioration rates in public use are higher than those reported from proving ground tests. Significant percentages of new cars are delivered from the factory maladjusted which has a significant effect on emissions. These maladjustments are worsened by automotive service personnel.     

Diagnosis and Repair of Excessively Emitting Vehicles

Abstract

Between 1991 and 1993, the California Air Resources Board (CARB) selected 1,115 vehicles from all across the South Coast Air Basin to evaluate the effectiveness of the state's existing biennial motor vehicle Inspection/Maintenance (I/M) or Smog Check program. The vehicles were chosen to represent the population of cars that "should fail" properly conducted inspections. The cars were emissions-tested at baseline and sent undercover to licensed I/M garages throughout the basin. Federal Test Procedure (FIT) emissions were measured again for cars that were repaired. In the second year of the study, the vehicles that could be reproduced were tested at the CARB to measure the level of emissions deterioration and any underhood changes in emission control systems. In the third year, the cycle of emissions testing and undercover inspections and repair was repeated.

This paper uses data from the study to explore the relationships between super emitting vehicles (defined here as vehicles whose emissions are several times California certification standards) and diagnostics and repair of their underhood emissions control systems. Also examined is their appearance and improvement during a three-year period that includes two cycles of inspection and repair. An important finding is that once normalized to account for differences in certification standards, the super emitting vehicles do not have a unique signature in terms of their underhood emission control system failure modes, mileage, or age, when compared with the average vehicle expected to fail a Smog Check inspection. However, they are more likely to be identified, diagnosed, and repaired effectively than other vehicles, although they continue to reappear over time.     

A Status Report: Air Pollution Control in Australia

All but one of the Australian States now have legislation to control Air Pollution. These are similar in broad principle and rely upon the system of prior approval and the use of emission limits. At the present time Victoria is the only State with legislation providing for the recycling of crankcase vent gases on motor cars. Methods being used to control pollution and future outlook and needs are discussed. At least 65 per cent of the crude oil requirements should be met by indigenous low sulfur oil by 1975. This fact and the imminent supply of natural gas to the four major cities and to the centers of heavy industrial development should result in a marked reduction in sulfur dioxide concentrations. A major outstanding problem is the lack of air pollution considerations in planning at regional and local government levels.     

An outline of the 1994-1998 European inspection and maintenance study: part I-design, tests, and results of experimental methods.

This paper provides an overview and the main results of a study aiming to evaluate current and alternative inspection and maintenance (I/M) programs to control emissions from in-use cars in Europe. For this purpose, a large number of passenger cars from five countries (France, Germany, Greece, the Netherlands, and the United Kingdom) were tested according to a common test protocol that included a variety of driving cycles and short tests, both legislative and specifically developed for this exercise. Evaluation of all test results was conducted with the objective of defining effective I/M test procedures and examining the potential of periodic I/M programs to reduce pollutant emissions and improve fuel economy of in-use cars. The results indicate that the current idle test used for catalyst-equipped cars in Europe is probably ineffective, while short transient loaded testing was found to offer higher potential in environmental terms. Regarding conventional gasoline cars, it is concluded that the idle test is sufficient, provided that the CO cut point is reduced and an HC test is added at high idle. Finally, the effectiveness of the free acceleration smoke test for diesels is questioned, while a transient cycle with continuous opacity measurement was found to be very promising. A companion paper further uses these results to analyze the likely cost-effectiveness on a per-country basis and discusses the possible effect of maintenance on emissions.     

Characterization of emissions from a variable gasoline/methanol fueled car.

In response to the occurrence of the increasingly severe ambient ozone exceedances, regional environmental managers are examining the possibility of a cleaner fuel for automobiles. At this time the leading candidate appears to be methanol. In anticipation of a shift to methanol, flexible-fueled automobiles capable of operating on gasoline and/or methanol are being developed. This study examines both the exhaust and evaporative emissions from a prototype General Motors Variable Fuel Corsica. Results are reported for tests conducted at temperatures of 40 degrees, 75 degrees, and 90 degrees F, and for fuels M0 M25, M50, M85, and M100. In addition to regulated emissions and fuel economy, emission rates for methanol, aldehydes, and a large number of hydrocarbon compounds were measured. The data indicate that increasing the fuel's methanol content does not affect the exhaust organic emission rate (calculated in accordance with the regulation) from flexible-fueled cars, but formaldehyde and methanol comprise increasingly greater portions of the organic material while hydrocarbons comprise less. Increasing fuel methanol content has no significant effect on exhaust regulated emission rates (organic material, carbon monoxide, and nitrogen oxides) nor on the composition of total hydrocarbons, except for methane, which increases substantially. The effect of ambient temperature on both exhaust and evaporative emissions is similar to its effect on gasoline cars: organic and carbon monoxide exhaust emissions increase substantially at the lower temperatures, and evaporative emissions increase steadily with increases in temperature.     

Photochemical Reactivities of Exhausts from 1966 Model Automobiles Equipped to Reduce Hydrocarbon Emissions

During the summer of 1966, a selected group of automobiles from the Cincinnati phase of the GSA study were used in an irradiation chamber study. The study was conducted to evaluate the photochemical air pollution potential of representative models of the equipped and unequipped automobiles. Only one set of automobiles, the unequipped Chevelles, produced exhaust capable upon irradiation of forming significant levels of oxidant and PAN. Neither the equipped Chevelles nor any of the Fords or Plymouths, whether equipped or unequipped, produced exhaust having the characteristics necessary to form oxidant or PAN upon irradiation. The eye irritation level reported by the panel upon irradiation of exhaust from unequipped Chevelles was much higher than that produced by the irradiated exhausts from any of the other types of automobiles. Overall, there does appear to be some small improvement with respect to eye irritation in comparing equipped with unequipped automobiles. To a large extent, the improvement in the air pollution potential of exhaust from equipped Chevelles compared to the unequipped Chevelles can be attributed to the reduction in the hydrocarbon to nitrogen oxide ratio. The irradiated exhaust from equipped Chevelles, except for aldehyde levels, is about the same in photochemical air pollution potential as are the exhausts from both equipped and unequipped Fords and Plymouths which are maintained under lean operating conditions. Such irradiation chamber measurements are related to exhaust not hydrocarbon reactivities. Hydrocarbon reactivities can be obtained by direct measurement of reactive and nonreactive hydrocarbons in the automotive emissions.     

Evaluation of retrofit crankcase ventilation controls and diesel oxidation catalysts for reducing air pollution in school buses

This study evaluates the effect of retrofit closed crankcase ventilation filters (CCFs) and diesel oxidation catalysts (DOCs) on the in-cabin air quality in transit-style diesel school buses. In-cabin pollution levels were measured on three buses from the Pueblo, CO District 70 fleet. Monitoring was conducted while buses were driven along their regular routes, with each bus tested three times before and three times after installation of control devices. Ultrafine number concentrations in the school bus cabins were 33–41% lower, on average, after the control devices were installed. Mean mass concentrations of particulate matter less than 2.5 μm in diameter (PM2.5) were 56% lower, organic carbon (OC) 41% lower, elemental carbon (EC) 85% lower, and formaldehyde 32% lower after control devices were installed. While carbon monoxide concentrations were low in all tests, mean concentrations were higher after control devices were installed than in pre-retrofit tests. Reductions in number, OC, and formaldehyde concentrations were statistically significant, but reductions in PM2.5 mass were not. Even with control devices installed, during some runs PM2.5 and OC concentrations in the bus cabins were elevated compared to ambient concentrations observed in the area. OC concentrations inside the bus cabins ranged from 22 to 58 μg m^?3 before and 13 to 33 μg m^?3 after control devices were installed. OC concentrations were correlated with particle-bound organic tracers for lubricating oil emissions (hopanes) and diesel fuel and tailpipe emissions (polycyclic aromatic hydrocarbons (PAH) and aliphatic hydrocarbons). Mean concentrations of hopanes, PAH, and aliphatic hydrocarbons were lower by 37, 50, and 43%, respectively, after the control devices were installed, suggesting that both CCFs and DOCs were effective at reducing in-cabin OC concentrations.     

Inspection and Maintenance for Reducing Automobile Emissions

EPA has recently evaluated several inspection and maintenance approaches for in-use vehicles that are potentially applicable to pre-1975 automobiles. The results of this evaluation are described and used to estimate the effecliveness and cost of inspection/maintenance for reducing total automobile emissions through 1985. It is estimated that inspection/maintenance programs for pre-1975 automobiles may be capable of achieving eight and ten percent reductions in total automobile emissions of HC and CO respectively until 1980 and two to three percent reductions in 1985. The need for inspection of automobiles of model year 1975 and later, and the potential applicability of present short-duration inspection procedures to these vehicles, are also discussed.     

Characterization of Emissions from a Variable Gasoline/Methanol Fueled Car

In response to the occurrence of the increasingly severe ambient ozone exceedances, regional environmental managers are examining the possibility of a cleaner fuel for automobiles. At this time the leading candidate appears to be methanol. In anticipation of a shift to methanol, flexible-fueled automobiles capable of operating on gasoline and/or methanol are being developed. This study examines both the exhaust and evaporative emissions from a prototype General Motors Variable Fuel Corsica. Results are reported for tests conducted at temperatures of 40°, 75°, and 90° F, and for fuels MO M25, M50, M85, and M100. In addition to regulated emissions and fuel economy, emission rates for methanol, aldehydes, and a large number of hydrocarbon compounds were measured. The data indicate that increasing the fuel's methanol content does not affect the exhaust organic emission rate (calculated in accordance with the regulation) from flexible-fueled cars, but formaldehyde and methanol comprise increasingly greater portions of the organic material while hydrocarbons comprise less. Increasing fuel methanol content has no significant effect on exhaust regulated emission rates (organic material, carbon monoxide, and nitrogen oxides) nor on the composition of total hydrocarbons, except for methane, which increases substantially. The effect of ambient temperature on both exhaust and evaporative emissions is similar to its effect on gasoline cars: organic and carbon monoxide exhaust emissions increase substantially at the lower temperatures, and evaporative emissions increase steadily with increases in temperature.     

Automotive Emissions After Hot and Cold Starts in Summer and Winter

Randomly selected passenger automobiles were driven over a 7.5-mile composite route in Cincinnati, Ohio. Samples of the exhaust gases were collected from each car by means of a proportional sampler and analyzed for gross hydrocarbons, carbon monoxide, carbon dioxide, and oxides of nitrogen. In addition, detailed analysis of the hydrocarbons was made. This included parafins, 1 through 8 carbon, olefins, 2 through 6 carbon, and aromatics, 6 through 10 carbon. This paper compares the differences in these emissions immediately after starting with “cold” engines as opposed to emissions from cars started with engines already warmed up or “hot.” This determination was made under both cold and warm weather conditions. A comparison is also made in air pollutants emitted from cars driven under the summer as opposed to the winter conditions normally encountered in Cincinnati, Ohio.     

Influence of fuel composition on polycyclic aromatic hydrocarbon emissions from a fleet of in-service passenger cars

The composition of exhaust emissions from eight in-service passenger cars powered by liquefied petroleum gas (LPG) and unleaded petrol (ULP) were measured on a chassis dynamometer at two driving speeds (60 and 80 km h⁻¹) with the aims of evaluating their polycyclic aromatic hydrocarbon (PAH) contents and investigating the effects of the type of fuel on vehicle performance, ambient air quality and associated health risks. Naphthalene, fluorene, phenanthrene, anthracene, pyrene, chrysene, benzo(a)anthracene and benzo(b)fluoranthene were the most prominent PAHs emitted by both ULP and LPG powered cars. The total emission factors of PAHs from LPG cars were generally lower than (but statistically comparable with) those of ULP cars. Similarly, the total BAP_eq of the PAHs emitted by LPG cars were lower than those from ULP cars. Multi-criteria decision making (MCDM) methods showed that cars powered by LPG fuel performed better than those powered by ULP fuel in term of PAH levels. The implications of these observations on the advantages and disadvantages of using ULP and LPG fuels are discussed.