2005年-世界发展银行全球_Impact_of_Improved_Stoves_on_Indoor_Air_Quality_in_Ulaanbaatar_Mongolia_76页_840kb

Summary of the Impact of Improved Stoves on Indoor Air Quality in Ulaanbaatar, Mongolia

Core Content

This report, published in November 2005, presents the findings of a pilot study conducted in Ulaanbaatar, Mongolia, to assess the impact of improved stoves on indoor air quality (IAQ). The study focused on particulate matter (PM) and carbon monoxide (CO) levels in households using different types of coal-fired stoves.

Key Findings

Indoor Air Quality Levels

• Indoor concentrations of PM and CO in all stove types exceeded Mongolian national standards for 24-hour exposure.
  • CO: Average 24-hour concentration was 9.5 ppm, significantly above the national standard of 2.6 ppm.
  • PM: Average 24-hour concentration was 730 μg/m³, far exceeding the national standard of 150–200 μg/m³.
• Indoor pollutant levels also exceeded World Health Organization (WHO) and U.S. Environmental Protection Agency (EPA) air quality guidelines.

Improved Stove Performance

• No statistically significant decrease in 24-hour average or 15-minute maximum concentrations of PM or CO was observed in homes with improved stoves.
• However, a non-significant trend toward lower CO levels was noted, suggesting potential improvements in combustion efficiency.
• Coal consumption was significantly lower in households using G2-2000 and TT-03 stoves compared to traditional stoves, with an average reduction of 5 kg per day.
• Fuel use was positively correlated with PM and CO concentrations.
  • Coal use showed significant correlations with all CO measures.
  • Wood use showed a significant correlation only with CO during the morning refueling period.

Ambient Pollution and Health Impacts

• High levels of ambient air pollution are likely contributing to the elevated indoor pollutant concentrations.
• The study suggests that future research should focus on ambient pollution levels, indoor pollution sources, and personal exposure to better understand the health implications.
• Respiratory diseases are the primary cause of morbidity and mortality among children aged 0–19 in Mongolia and the fifth leading cause of death for the overall population.
• Pneumonia is a major contributor to infant mortality in Mongolia, especially during winter months when indoor air pollution is at its peak.

Methodology

Study Design

• A stratified sampling approach was used to collect data from 65 households in Ulaanbaatar's ger districts.
• 22 households used traditional stoves, 20 used TT-03 stoves, and 23 used G2-2000 stoves.
• The study aimed to assess the impact of improved stoves on IAQ in terms of CO and PM levels.

Data Collection

• 24-hour monitoring was conducted to capture the full range of indoor air pollution levels.
• Field work took place in January 2004, with data collected on:
  • Home sizes
  • Indoor and outdoor temperatures
  • Age of stove
  • Fuel use and refueling frequency
  • Position of monitors relative to chimneys
  • Cigarette smoking

Equipment Used

• UCB Particle Monitor: Measures PM, temperature, and relative humidity. It has two independent sensors for PM measurement.
• HOBO Data Logger: Measures CO levels.
• Both monitors were used to ensure comprehensive and accurate data.

Statistical Analysis

• ANOVA showed that traditional stoves were generally older than improved stoves.
• Multivariate regression was used to control for variables such as fuel use, temperature, and refueling frequency.
• Bivariate regression was used to examine the relationship between fuel use and pollutant levels.

Main Stove Types Studied

• Traditional Stoves: Large combustion chambers, no adjustable air intakes or chimney baffles.
• TT-03 Stoves: Improved design with metal flanges, clay interior lining, and chimney valve for better heat radiation and burn control.
• G2-2000 Stoves: Smaller combustion chamber, internal chimney baffles, and better fuel efficiency.

Key Recommendations

• The study highlights the need for more detailed research into ambient air pollution and its impact on indoor air quality.
• Improved stoves may reduce fuel consumption and improve combustion, but further studies are required to confirm their effectiveness in reducing pollutant exposure.
• Given the high burden of respiratory diseases in Mongolia, reducing indoor air pollution should be a priority in public health initiatives.

Conclusion

• While improved stoves may offer some benefits in terms of combustion efficiency and fuel savings, the study found no statistically significant improvement in indoor air quality in terms of PM and CO concentrations.
• The high ambient pollution levels in Ulaanbaatar likely play a major role in the poor IAQ observed.
• The report underscores the importance of addressing indoor air pollution as a key factor in improving health outcomes, particularly among vulnerable populations such as children and the elderly.

Summary of Stove Characteristics

Additional Information

• The ESMAP program, administered by the World Bank, aims to support energy sector development in low-income and emerging economies.
• The study was conducted in collaboration with the Environmental Health Sciences Division at the University of California, Berkeley.
• Field team and monitoring protocols are detailed in annexes.
• Contact information for ESMAP is available on their website: www.esmap.org or via email: esmap@worldbank.org.