Exposure to Cigarette and Biofuel Smoke May Negatively Affect the Height of Young Children

Various studies have proposed that exposure to carcinogenic fumes, traditional fuels, and biofuels may negatively affect the growth and development of children.  Especially within developing countries, childhood exposure to cigarettes, tobacco, fuels, and biofuels is widespread.  Kyu et al. (2009) specifically investigated whether or not the exposure of children under five years old to cigarette smoke and biofuels is correlated with their height relative to their age.  Using multilevel regression analyses, the researchers determined that exposure to maternal smoking negatively affected the height of the children in only three of the developing countries studied while biofuel exposure negatively affected height across all seven countries. Moreover, for children under five years old, biofuel exposure is connected with stunting and severe stunting in height.  Thus, this study demonstrated that such exposures to cigarettes and biofuels might hinder childhood growth for young children in developing countries. —Christina Mainero
Kyu, H.H., Georgiades, K., and Boyle, M.H., 2009. Maternal smoking, biofuel smoke exposure and child height-for-age in seven developing countries. International Journal of Epidemiology, 38, 1342–1350.

 In this study, Kyu et al. sought to examine the effects of maternal smoking and biofuel exposure on young children due to the rise of smoking and biofuel use in developing countries, the fact that maternal smoking may increase a child’s likelihood of exposure, the paucity of information regarding the effects of maternal smoking on children under five years old, and the increased use of biofuels in developing countries.  For the seven developing countries studied, data were collected between 2005 and 2007.  In setting up their sampling scheme, the researchers divided each country into clusters of roughly fifteen to twenty women.  Within each cluster, they measured the heights of the children and also conducted interviews with their mothers.  In some clusters, they questioned a subset of men regarding their daily activities and habits.  In doing this, the researchers were able to assess the effects of maternal smoking, exposure to smoking by other members of the house, and biofuel exposure on the height of the children.  Factors such as child age, child gender, breastfeeding initiation, mother’s age, mother’s educational history, estimated birth size of the child, household wealth and country acted as covariates.
Based on the data collected, Kyu et al. concluded that the children of women with fewer financial resources, less education, and more children tend to have increased smoking and biofuel exposure.  Additionally, their regression models indicated that maternal smoking correlated negatively with height in Cambodia, Namibia, and Nepal; correlated positively with child height in Moldova; and showed no significant correlation either way in the remaining countries.   Exposure to non-maternal smoking and biofuels, however, demonstrated a significant negative correlation with the height of young children. Moreover, biofuel exposure appears to be connected with stunting and severe stunting within all of the countries studied. 
However, the researchers also noted several limitations of this study.  Specifically, they mentioned the fact that there was no data regarding maternal smoking and biofuel exposure during pregnancy, which may be an important factor influencing the height of the children.  Furthermore, actual biofuel exposures were measured indirectly rather than directly based on the type of biofuel used for cooking and daily activities.  Additionally, the study lacked information regarding the duration of exposure.  Studies such as these, though important for looking into potential correlations, do not conclusively establish causation.  Yet, this study is significant because its conclusions suggested that there might be notable detrimental health effects associated with biofuel use as well as maternal smoking.  Such heath effects must be considered in evaluating whether or not biofuels are plausible alternatives to traditional, petroleum-based fuels.

Biofuels Significantly Reduce the Health Hazards Caused by Polycyclic Aromatic Hydrocarbons

Several previous studies have suggested that various fuels emit carcinogenic polycyclic aromatic hydrocarbons (PAHs).  Ballesteros et al. (2009) examined the relationship between the amount of oil, the type of oil, and the carcinogenic potential of three biofuels and a conventional fuel.  The researchers conducted a chemical speciation of the sixteen most hazardous PAHs associated with fuel combustion using a newly developed method combining processes of thermal extraction, solid-phase micro-extraction (SPME), and GC/MS analysis.  The researchers found that using biofuels rather than conventional fuels reduced total PAH emissions as well as the risks to human health from these emissions.  Furthermore, they determined that PAH emissions depend on the oil used for the transesterfication process. —Christina Mainero
Ballesteros, R., Hernandez, J.J., Lyons, L.L., 2009.  An experimental study of the influence of biofuel origin on particle-associated PAH emissions. Atmospheric Environment 44, 930–938.

 Ballesteros et al. inspected the mutagenicity of the sixteen PAHs considered to be hazardous to human health.  To determine the impact on human health of the type and origin of vegetable oil used for transesterfication compared with a reference fuel, the researchers conducted a chemical speciation on these compounds.  Additionally, they collected data on the gaseous non-methane hydrocarbons emissions, the diesel particulate matter emissions, volatile organic matter emissions, mean particle diameter, and particle opacity for the biofuels and the reference fuel.  In order to properly compare the emissions for these different fuels, the researchers made sure that the exhaust gas recirculation ratio remained constant.  Moreover, they examined all of the fuels in two different operating modes: extraurban and urban.  The three biofuels used in this study were rapeseed methyl ester (RSM), waste cooking oil methyl ester (WCOM), and waste cooking oil ethyl ester (WCOE), which were then compared to the conventional reference fuel.
To accurately gauge the health risks associated with the different fuels, Ballesteros et al. used a conversion factor, called the toxicity equivalent factor (TEF).  This conversion factor provided them with a carcinogenic equivalence sum (KE) that represented the inherent carcinogenicity of each of these PAHs.  All three biofuels showed a reduction in KE, indicating that biofuel emissions are less hazardous to human health than conventional fuels.  For the RSM WCOM, and WCOE, there was a notable reduction in the emissions of the PAHs with higher molecular weights, which tend to have more carcinogenic potential.  Unlike the RSM, the biofuels originating from cooking waste oils emitted significantly higher levels of lighter PAHs than the conventional fuels.  However, the health risk to humans was still lower than that associated with the use of conventional fuels because PAHs with lower molecular weights tend to be far less carcinogenic than those with high molecular weights.  The researchers concluded that using biofuels not only reduces the overall amount of PAH emissions, but also diminishes negative health impacts when compared with conventional fuels.  Moreover, they determined that the type of oil used for the process of transesterfication significantly influences the emission of heavy or light PAHs, which, in turn, dictates their effects on human health.  Thus, this study suggested that certain biofuels may be less toxic to human health than conventional biofuels, advancing the case for biofuels as plausible alternatives to conventional fuel sources.

NOX Emissions from Malaysian Oil Palm Plantations May Lead to Unhealthy Levels of O3

Hewitt et al. (2009) examined the effect of converting rainforests to oil palm plantations in Malaysia. The production of palm oil has increased, partially due to the fact that the biofuel has been touted as “environmentally-friendly.”  However, using various measurements and models, the researchers discovered that oil palm plantations actually emit a far greater amount of nitrous oxides and volatile organic compounds (VOCs) than rainforests.  This is especially problematic as nitrous oxides and VOCs can react in the presence of sunlight to create O3, which is classified as an air pollutant with the potential to seriously damage human health, among other things.  Should nitrous oxides in Malaysia reach levels comparable to those over rural North America and Europe, it is likely that O3 levels could reach over 100 ppbv, well above the level known to be dangerous to human health.  Thus, the authors concluded that nitrogen emission management schemes must be developed. — Christina Mainero
Hewitt, C., MacKenzie, A., DiCarlo, P., Di Marco, C., Dorsey, J., Evans, M., Fowler, D., Gallagher, M., Hopkins. J., Jones, C., Langford, B., Lee, J., Lewis, A., Lim, S. McQuaid, J.. Misztal, P., Moller, S., Monks, P., Nemitz, E., Oram, D., Owen, S., Phillips, G., Pugh, T., Pyle, J., Reeves, C.,  Ryder, J., Slong, J., Skiba, U., and Stewart, D., 2009. Nitrogen management is essential to prevent tropical oil palm plantations from causing ground-level ozone pollution. PNAS 106, 18447–18451.

In their investigation, Hewitt et al. took fully integrated and comprehensive biosphere-to-atmosphere flux measurements and modeled the atmospheric chemistry of rainforests and oil palm plantations in the tropics.  They determined that VOC emissions from both types of land tend to be dominated by isoprene, though the plantations emit five times as much of it as the rainforests, evidently because of biogenic emissions from oil palm trees.  The researchers suggested that the emissions of VOC compounds from the oil palm plantations were greater than those of European cities, such as London.  Moreover, their measurements suggested that oil palm plantations emit roughly 2.5 times as much nitrous oxide as rainforest land, a result of vehicle exhaust, combustion, and soil nitrogen fertilization.
Thus, the researchers demonstrated that land use change for the purpose of producing more “environmentally-friendly” biofuels can be problematic.  Their results supported the notion that converting rainforest land to oil palm plantations for biofuel production purposes leads to increased emissions of nitrous oxides and volatile organic compounds (VOCs).  Although levels of O3 have not yet increased substantially, Hewitt et al. believed that ozone emissions will rise with the increased industrialization and production of nitrous oxides in the area.  Such an increase in emissions will negatively impact human health.  Moreover, the researchers noted the importance of controlling and managing nitrogen levels at local and regional scales in order to prevent significant changes in the air quality.  Because of its potential cost to human health and crop productivity, the researchers argued that oil palm biofuel production might be fairly short-lived.

Biomass Fuel Combustion is a Potential Danger to Human Health in Cusco, Peru

Pearce et al. (2009) studied the use of biofuels for household energy in Cusco, determining that the combustion of these fuels resulted in potentially dangerous levels of PM2.5 and CO emissions.  Combined with the hypoxic stress of high-altitude living, this is a very real threat to human health.   The study concluded that the levels of PM2.5 emissions present in kitchens were 4.4 times higher than those in secondary rooms and 9.4 times higher than those in outside entryways.  Similarly, the CO concentrations were highest in kitchens, with concentrations averaging 4.8 times more than secondary rooms and 3.3 times more than outdoor entryways.  They found that the highest levels of CO and PM2.5 emissions occurred with the combustion of dung, followed by wood, kerosene, and gas, respectively.—Christina Mainero
Pearce, J., Aguilar-Villalobos, M., Rathbun, S., Naeher, L., 2009.  Residential exposures to PM2.5 and CO in Cusco, a high altitue city in the Peruvian Andes: A Pilot Survey. Archives of Environmental and Occupational Health 64, 278-282.

The goal of this study by Pearce et al. was to measure the average indoor and outdoor CO and PM2.5 emissions at 41 residences in Cusco during the preparation of meals in the morning, afternoon, and evening.  Measurements of CO and PM2.5 emissions were taken at breathing level to mimic human exposure to these pollutants.  The measurements were taken in three different locations in each residence—the kitchen, the room designated as the second most used room, and the front entryway outside each home.  To minimize any discrepancies, the concentration levels of both CO and PM2.5 were collected simultaneously.
Statistical analyses of the data on PM2.5 emissions demonstrated that emissions caused by the combustion of wood are significantly higher than those caused by kerosene, while those from dung are significantly higher than those caused by gas.  Furthermore, in secondary rooms, PM2.5 emissions from wood combustion were significantly higher than those from gas.  Similarly, wood emissions of CO in kitchens were significantly higher than gas emissions.  Overall, the median CO and PM2.5 emissions were highest for the combustion of dung, followed by wood, kerosene, and gas, respectively.  Kitchens, where the food preparation occurred, tended to have the highest concentrations of CO and PM2.5, followed by the secondary rooms and then the outdoor entryways.  Furthermore, the general trend seemed to show that the greatest concentration of pollutant emissions occurred in the morning, which the authors suggested was due to the fact that large meals tend to be prepared in the morning and simply reheated throughout the rest of the day in Cusco.
However, Pearce et al. noted that there were several limitations in their study, including the small sample size, the shortness of the data collection period, the lack of an even distribution of measurements across the different fuel types, and the fact that the measurements of pollutant concentrations did not actually measure the number of human exposures to CO and PM2.5 emissions.  Despite these limitations, this study is interesting in that it notes the potential dangers of the combustion of biofuels and fuels in the preparation of food, particularly in developing countries, such as Peru.

Health Hazards Caused by Peat Biofuel Combustion are Minimal in Tartu

Orru et al. (2009) investigated the potential health impacts of the increased combustion of peat biofuel in Tartu, Estonia, by calculating the dispersion and deposition of particulate matter emissions and estimating the number of years of life lost (YLL) caused by such emissions.  Using the AEROPOL model and AirQ software to illustrate and identify the effects on health, the researchers concluded that peat biofuel combustion caused an average of 55.5 YLL each year per 100,000 individuals.  However, this value was marginal in comparison to their estimated value of 1539 years of life lost from all environmental sources of pollution in Tartu each year.  Thus, they concluded that the hazards to human health caused by increased emissions from peat biofuel production were insignificant when compared with overall particulate matter emissions from traffic pollution and local heating.—Christiana Mainero
Orru, H.,  Kaasik, M., Merisalu, E., Forsberg, B., 2009. Health impact assessment in case of biofuel peat—Co-use of environmental scenarios and exposure-response functions.  Biomass and Bioenergy 33, 1080-1086.

Orru et al. sought to assess whether or not the transition from gas to peat biofuel combustion would seriously impact the health of individuals due to potential changes in air quality.  To calculate and estimate these effects, their model included the following measurements: a calculation of emissions, an assessment of the ambient air quality, the identification of at-risk individuals, and a quantification of the health effects.  Because peat content varies widely in composition, which can affect its health implications, they determined the percentages of ash, sulfur, trace elements, and heavy metals prior to conducting the study.  The AEROPOL model was used to calculate the average emission of pollutants from boiler houses.  The researchers created dispersion maps and compared them with population density information to determine the boundaries of the exposure area near the boiler houses.   The AirQ software then calculated the average YLL in the area.  To assess base-line air quality, Orru et al. conducted official air pollution monitoring of PM, S02, NO2, and CO emissions in five different areas throughout the city.
The results of this study demonstrated that the most health hazardous emissions from the boiler houses, the PM2.5 emissions, dispersed in a fairly small area and persisted for only a short period of time.  According to the researchers, the mean annual pollutant concentrations from other sources were well over 20 times higher than those from boiler houses.  For those individuals in the more highly exposed areas, the calculated YLL per year was 36, while it was 19.5 for those outside the exposed area.  However, these values seem almost negligible when considering the fact that the total YLL induced by all pollution sources each year has an estimated value of 1539.  The concentrations of S02, CO, and 03 from the boiler houses were low. 
However, the researchers noted that there were some shortcomings in their analysis.  For example, the air quality in Tartu was measured only once each year over a two-week period, which may not have allowed the most accurate characterization of air quality.  Additionally, the 95% confidence interval on the YLL was large, which was partially due to the fact that YLL was determined by a number of different factors.  Although there were some uncertainties associated with this study, the researchers concluded that the YLL caused by peat burning was not a significant threat to air quality or human health.