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Rural kitchens of solid-fuel burning households constitute the microenvironment responsible for the majority of
human exposures to health-damaging air pollutants, particularly respirable particles and carbon monoxide. In China
alone, 1.06 billion people were exposed to indoor air pollution from household combustion of solid fuels such as
coal, wood, and crop straw in 2001. Addressing health impacts through cooking fuel and stove interventions calls
for time-resolved data characterizing average indoor air quality and peak pollution episodes, which dominate women's
and children's exposures; analysis of fuel, stove, and behavioral factors as determinants of indoor air quality;
and field data to substantiate operations and guide implementation of promising technologies.
Portable nephelometers facilitate logistically simple, precise, time-resolved characterization of particles but
must contend with aerosols that are highly variable in terms of chemical content, size, and relative humidity.
Observations from highly polluted Chinese kitchens, where gravitationally determined 24-h average respirable particle
concentrations were as high as 700 mg/m3, showed that where relative humidity remained below 95%, nephelometric
response was strongly linear despite complex mixtures of aerosols and variable ambient conditions. Where 95% relative
humidity was exceeded for even a brief duration, nephelometrically determined 24-h mean particle concentrations
were nonsystematically distorted relative to gravitational data. This nonsystematic distortion is particularly
problematic for rural exposure assessment studies, which emphasize upper quantiles of time-resolved particle measurements
within 24-h samples.
Time-resolved wintertime measurements of carbon monoxide and respirable particles (RSP) enable exploration of peak
pollution periods in a village in Jilin Province, China, characterized by household use of both coal and biomass,
as well as several "improved" (gas or electric) fuels. Our data indicate a 6-fold increase in peak 1
h PM (1.9 mg/m3) concentrations relative to 24 h mean PM (0.31 mg/m3). Peak 1 h CO concentrations (20.5 ppm) routinely
approached and often (27%) exceeded the World Health Organization's 1 h guideline of 26 ppm, although the vast
majority (95%) of kitchens were within China's residential indoor air quality guideline for CO on a 24 h basis.
Choice of heating fuel and household smoking status were significant predictors of indoor air quality. Whether
solid or "improved" (gas or electric) fuel was used for cooking had an even stronger effect, but in the
opposite direction from expected, on both peak and daily average measures of air pollution. Due to the primary
role of heating as a determinant of wintertime indoor air quality in northern Chinese villages, health-oriented
interventions limited to provision of improved cooking fuel are insufficient.
Chinese national and provincial, as well as international rural development institutions, have identified generation
of producer gas from agricultural residues as a promising option for supplying clean-burning, inexpensive, and
convenient household energy. Although the technology is promising, field data from village projects are scarce.
A team trained in cultural anthropology, environmental health sciences, and engineering recently visited Jilin
province, China, to investigate operations of three village-scale producer gas projects. One locally initiated
project was operating on a regular basis and supplying a substantial fraction of village cooking needs. The other
two projects had not operated since their initial demonstrations. Technical, economic, organizational, and cultural
factors, including a lack of evaluative feedback from local projects to provincial level coordinators, hamper the
development of village-scale producer gas projects in Jilin province. |
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Susan L. Fischer, Ph.D., M.S.E., was appointed in September 2006 as Science, Technology,
and Health Policy Advisor to the Chair of the Air Resources Board (ARB). Prior to joining ARB, Dr. Fischer was
a postdoctoral scholar of Environmental Health Sciences at the University of California, Berkeley's School of Public
Health, where she managed and conducted an independent field investigation of a rural energy project in Jilin province,
China. Dr. Fischer's research in rural China comprised public health inquiry into indoor air quality and its determinants,
engineering analysis of particle-monitoring equipment in a rural field context, and ethnographic research on household
impacts and socio-cultural dynamics associated with a village-scale energy project.
Dr. Fischer also has experience as a laboratory combustion researcher with Princeton University, where she earned
her M.S.E. investigating turbulent flow reactor chemical kinetics of dimethyl ether, a fuel with applications in
diesel engines and in household cooking stoves. |
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For more information on this
Seminar please contact:
Peter Mathews at (916) 323-8711 or send email to: pmathews@arb.ca.gov
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For a complete listing of
the ARB Chairman's Series and the related documentation for each one of the series please check this page
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