Grantee Research Project Results

1999 Progress Report: Effect of Ammonium Bisulfate and Carbon Black Particles Inhaled Alone and in Combination on Airway Reactivity in Actively Sensitized Brown-Norway Rats

EPA Grant Number: R826778
Title: Effect of Ammonium Bisulfate and Carbon Black Particles Inhaled Alone and in Combination on Airway Reactivity in Actively Sensitized Brown-Norway Rats
Investigators: Benson, Janet M.
Current Investigators: Benson, Janet M. , Cheng, Yung-Sung , Bice, David E. , Barrett, Edward G. , Powell, Quint H.
Institution: Lovelace Biomedical & Environmental Research Institute
EPA Project Officer: Chung, Serena
Project Period: October 1, 1998 through September 30, 1999 (Extended to December 30, 2000)
Project Period Covered by this Report: October 1, 1998 through September 30, 1999
Project Amount: $199,035
RFA: Health Effects of Particulate Matter and Associated Air Pollutants (1998) RFA Text |  Recipients Lists
Research Category: Particulate Matter , Human Health , Air

Objective:

The purpose of this research is to determine the relationship between increases in airborne aerosol mass concentrations of three models of major components of PM10-pure ammonium bisulfate (ABS), pure carbon black (CB, a surrogate for fine soot particles), and ABS-coated CB (ABS/CB)-and changes in pulmonary function and airway hyperreactivity. Specifically, we will investigate the roles of the three inhaled pollutant particle types of relevant particle size and concentration on pulmonary function and airway reactivity in allergen-sensitized male Brown-Norway (BN) rats, a rodent model for human extrinsic asthma. The experimental approach is to compare the potency of CB particles and ABS particles with ABS/CB at equivalent mass concentrations to cause significant adverse changes in pulmonary function and/or increase in allergen-specific or nonspecific increases in airway hyperreactivity.

Progress Summary:

Due to scheduling conflicts, we were unable to complete the study within the original 1-year funding period. We received a no-cost extension until June 30, 2000. Our progress to date is as follows:

Development of the Ammonium Bisulfate Aerosol. Ammonium bisulfate aerosol was generated by heating ammonium bisulfate in a quartz sample boat with a tube furnace. A vaporization temperature of 260oC followed by a cooling temperature of 100oC (second furnace) produced a suitable aerosol with a count median diameter (CMD) of approximately 56 nm and a mass median diameter (MMD) of 103 nm. The aerosol concentration generated was determined not to be sufficient for exposure of rats in a whole-body exposure chamber, as described in the study proposal. Therefore, the rats in these studies will be exposed nose-only.

Carbon Black Aerosol. Carbon black aerosols with a MMD of approximately 100 nm will be generated using a Palas aerosol generator. The exposure system is under construction and will be available for exposures in early May.

Ovalbumin and Acetylcholine Challenge Aerosols and Pulmonary Function System. The chamber for measuring pulmonary function in rodents challenged with ovalbumin (OA) and acetylcholine (ACh) aerosols was set up. An aerosol generation system consisting of a Micro-Mist aerosol nebulizer, a glass conditioning plenum, a Kr-85 discharge source/heating chamber, a filtered air mixing instrument, a demand dilution loop, and the associated air delivery and exhaust lines was constructed. The rodent chamber for pulmonary function has been connected to the aerosol generation system. The mass median aerodynamic diameter of a saline aerosol produced by the nebulizer and passing through conditioning plenum was 0.98 mm with a geometric standard deviation of 1.9.

Future Activities:

During the remaining portion of the funding period, we will:

• Develop and characterize an ammonium bisulfate-coated carbon black aerosol. The aerosol will be generated by introducing carbon black particles generated by a Palas generator into the ammonium bisulfate vapors.

• Conduct exposures of ovalbumin sensitized Brown-Norway rats to 0.1 mm aerosols of carbon black, ammonium bisulfate, and ammonium bisulfate-coated carbon black for 6 hours.

• Measure the effect of the particle exposures on lung resistance, dynamic lung compliance upon ovalbumin inhalation. Determine whether particle exposure reduces the concentration of inhaled ACh required to increase lung resistance by a factor of two. Determine titles of ovalbumin-specific IgG and IgE in serum. Determine the inflammatory response in lungs by measuring protein concentration and total and differential counts of cells in bronchoalveolar lavage fluid.

Supplemental Keywords:

ambient air, health effects, asthma, sensitive populations, particles, sulfates, air pollution, particulate matter., RFA, Air, Scientific Discipline, Health Risk Assessment, Chemistry, particulate matter, Biology, Environmental Chemistry, Toxicology, aerosols, inhalability, urban air, ambient aerosol, brown Norway rats, cellular physiology, lung inflammation, mortality, cellular biology, laboratory animals, morbidity, pulmonary, Acute health effects, particulates, ammonium bisulfate, chronic health effects, analytical chemistry, microbiology, air toxics, carbon black

Progress and Final Reports:

Original Abstract

2000

Final Report