Characterization of Fine Particle Air Pollution in the Indian Subcontinent

This thesis characterizes the mass and chemical composition of the fine particle air pollution over several cities in South Asia and quantifies how major sources impact the observed levels by using Chemical Mass Balance modeling with organic compounds as tracers. During February 1999, as part of the INDOEX program, a study was conducted to measure the size distribution and chemical composition of the fine particles in a remote island in Maldives off the coast of India. We found that the fine particle concentrations were comparable to those found in major cities in the United States, and were surprisingly high for a background site. 10-day backwind trajectories pointed the source region towards the Indian subcontinent; other INDOEX studies confirmed the presence of a thick haze layer over the Indian Ocean and the subcontinent during the time of the experiment. Motivated by these findings, a detailed analysis of ambient PM2.5 was carried out in Delhi, Mumbai, Kolkata, and Chandigarhfour cities located upwind of the island in Maldives. Seasonality of the fine particle concentrations was observed in each of these cities with the highest concentrations occurring during the wintertime and the lowest concentrations during the summer. Size distribution and chemical composition of the fine particle emissions from five Bangladeshi biomass (rice straw, coconut leaves, dried cow dung, synthetic biomass log, and jackfruit wood) and three Asian coals (Bangladeshi, Indian, and Chinese) were characterized and important source signatures were identified. Finally, recently developed chemical tracer techniques were applied to the ambient samples from North India to differentiate between the contributions from the many different source types. The emission profiles and source signatures from the source tests conducted previously along with the ones conducted using the Indian Subcontinent fuels were used as inputs to the model. These results serve several purposes. First, they provide a description of the mass and detailed inorganic and organic chemical characteristics of fine particulate matter conducted for the first time ever in this region. Second, the source apportionment study will help to define the relative importance of those sources that should be included within an air quality control program. Chemical tracer techniques are particularly attractive for application in regions that have not been studied previously because they are able to yield rapid insights into the causes of a local air pollution problem before the completion of an accurate emissions inventory. Third, the source tests results will prove useful in constructing and evaluating regional emission inventory and assessing source impacts on air quality. Fourth, this work has been carried out with collaborations from Georgia Tech and several other Indian research institutions where pollution control personnel in India was trained in the operation of air sampling equipments that were left for continued monitoring, thus contributing to technology transfer and knowledge transfer from the US.Ph.D.Committee Chair: Russell, Armistead; Committee Member: Bergin, Michael; Committee Member: Ingall, Ellery; Committee Member: Weber, Rodney; Committee Member: Zheng, Me

Closure between aerosol particles and cloud condensation nuclei at Kaashidhoo Climate Observatory

Predicting the cloud condensation nuclei (CCN) supersaturation spectrum from aerosol properties is a fairly straightforward matter, as long as those properties are simple. During the Indian Ocean Experiment we measured CCN spectra, size-resolved aerosol chemical composition, and aerosol number distributions and attempted to reconcile them using a modified form of Köhler theory. We obtained general agreement between our measured and modeled CCN spectra. However, the agreement was not as good during a time period when organic carbon comprised a quarter of the total mass of the aerosol in the submicron size range. The modeled concentrations overpredict those actually measured during that time period. This suggests that some component, presumably organic material, can inhibit the uptake of water by the electrolytic fraction of the mass

Characterization of organic aerosols emitted from the combustion of biomass indigenous to South Asia

Throughout South Asia biomass is commonly used as a fuel source for cooking and heating homes. The smoke from domestic use of these fuels is expected to be a major source of atmospheric particulate matter in the region and needs to be characterized for input in regional source apportionment models and global climate models. Biomass fuel samples including coconut leaves, rice straw, jackfruit branches, dried cowdung patties, and biomass briquettes manufactured from compressed biomass material were obtained from Bangladesh. The fuel samples were burned in a wood stove to collect and characterize the particulate matter emissions. The bulk chemical composition including total organic and elemental carbon, sulfate, nitrate, ammonium and chloride ions, and bulk elements such as potassium and sodium did not show conclusive differences among the biomass samples tested. Unique features, however, exist in the detailed organic characterization of the combustion smoke from the different sources. The organic compound fingerprints of the particulate matter are shown to be distinct from one another and distinct from North American wood fuels. Fecal stanols including 5β-stigmastanol, coprostanol, and cholestanol are found to be good molecular markers for the combustion of cowdung. Additionally, the patterns of methoxyphenols and plant sterols provide a unique signature for each biomass sample and are conducive as source apportionment tracers

Characterization of organic aerosols emitted from the combustion of biomass indigenous to South Asia

Throughout South Asia biomass is commonly used as a fuel source for cooking and heating homes. The smoke from domestic use of these fuels is expected to be a major source of atmospheric particulate matter in the region and needs to be characterized for input in regional source apportionment models and global climate models. Biomass fuel samples including coconut leaves, rice straw, jackfruit branches, dried cowdung patties, and biomass briquettes manufactured from compressed biomass material were obtained from Bangladesh. The fuel samples were burned in a wood stove to collect and characterize the particulate matter emissions. The bulk chemical composition including total organic and elemental carbon, sulfate, nitrate, ammonium and chloride ions, and bulk elements such as potassium and sodium did not show conclusive differences among the biomass samples tested. Unique features, however, exist in the detailed organic characterization of the combustion smoke from the different sources. The organic compound fingerprints of the particulate matter are shown to be distinct from one another and distinct from North American wood fuels. Fecal stanols including 5b-stigmastanol, coprostanol, and cholestanol are found to be good molecular markers for the combustion of cowdung. Additionally, the patterns of methoxyphenols and plant sterols provide a unique signature for each biomass sample and are conducive as source apportionment tracers

Source apportionment and characterization of ambient fine particles in Delhi, Mumbai, Kolkata, and Chandigarh

Issued as final repor

The cost of convenience; Air pollution and noise on freeway and arterial light rail station platforms in Los Angeles

Light rail transit (LRT) systems constitute one of the most sustainable public transportation modes and transit agencies have increasingly constructed LRT lines along the median of roadways to reduce land acquisition costs and traffic conflicts. Despite these conveniences, few studies have examined the air pollution and noise exposures for passengers on LRT station platforms within freeway or arterial medians. In response, we monitored particle number count (PNC) concentrations and noise levels on 17 station platforms in the Los Angeles metro system in summer 2012 and assessed differences between freeway and arterial platforms. We visited each station on average 7 times for approximately 19 min with two teams carrying a full set of instruments. As expected, impacts were higher on green line platforms in the center of a grade-separated freeway compared to blue line platforms in the center of an arterial due to being in close proximity to greater traffic volumes. Overall, freeway-arterial platform differences were 35,100 versus 20,000 particles/cm3 for PNC and 83 versus 62 dBA for noise. This average noise intensity on green line platforms was four times that on blue line stations. We also found that PNC concentrations were significantly higher at open air monitoring platform positions compared to standing under a shade canopy (about 2000 particles/cm3 higher), but that noise levels were significantly lower at open air positions compared to under canopy positions (about 3.2 dBA lower). Results identify important factors for transport planners to consider when locating and designing in-roadway LRT platform