In developing countries, aerosol particles damage the health of hundreds of millions of people. Migration from the country side to megacities increases emissions and exposure to particles. Some countries have started to limit emissions based on particulate mass, but this may increase particle number concentrations. In this study we discuss some earlier measurements carried out in the developing world and compare results from one-week measurement campaigns concerning the particle number size distribution and PM10 mass concentrations in New Delhi, India and Beijing, China. Our results show that submicron particle concentrations are high in both places. The average PM10 concentration was 360 mu g/m(3) in New Delhi and 120 mu g/m(3) in Beijing. The corresponding total particle number concentrations in the size range 3-800 nm were 63 000 cm(-3) and 35 000 cm(-3). Number and mass concentrations and their characteristics showed significantly different behaviour between these two locations, which stresses the importance of long-term simultaneous measurements of both quantities in different types of megacities.

In this study, we developed a method that can easily and accurately measure human exhaled air (eNO). The method was successfully used to measure eNO of ten adult volunteers, who had a 9-day average of 9. 4 3. 3 mug·m~(-3) (mean SD)eNO. An analysis of the data shows correlations between eNO and ultrafine particles , suggesting the inflammatory effects of ultrafine particles in healthy adults.建立了一个简易、准确的人体呼出气中NO(eNO) 测量方法,并利用该方法测量成人呼出气中NO的含量,10 名志愿者9d的NO 平均值为9.43.3mug·m~(-3).对测得的NO 值与大气颗粒物浓度进行相关性分析及回归分析,初步分析了超细颗粒物与eNO 的相关性,这些相关性说明了大气超细颗粒物对人体呼吸系统健康存在的潜在影响,而eNO 可作为这一效应的生物标记物.

Continuous measurements of aerosol number size distributions from 3 nm to 10 mum have been first performed within the city area of Beijing since March 2004. Size distributions of the first 45 measurement days (March 05 to April 18, 2004) were investigated in terms of their high variability. Two dust storm events were observed indicated by high number concentrations greater than 1 mum and mass concentrations around 1 mg m(-3). Continental highly polluted air was observed during 12 days indicated by a number peak in the accumulation mode range, and submicrometer volume concentrations above 150 mum 3 cm(-3) were observed. Newly formed particles with more than 100,000 cm(-3) were observed on 25 days when the particle surface area concentration drops below a critical value (100-2000 mum 2 cm(-3)) because of clean air from the north. Measurements show only a slight growth (similar to1 nm h(-1)) of the particles indicating that they are produced within the city area of Beijing.