Sources of variation for indoor nitrogen dioxide in rural residences of Ethiopia

Abstract

BackgroundUnprocessed biomass fuel is the primary source of indoor air pollution (IAP) in developing countries. The use of biomass fuel has been linked with acute respiratory infections. This study assesses sources of variations associated with the level of indoor nitrogen dioxide (NO2).Materials and methodsThis study examines household factors affecting the level of indoor pollution by measuring NO2. Repeated measurements of NO2 were made using a passive diffusive sampler. A Saltzman colorimetric method using a spectrometer calibrated at 540 nm was employed to analyze the mass of NO2 on the collection filter that was then subjected to a mass transfer equation to calculate the level of NO2 for the 24 hours of sampling duration. Structured questionnaire was used to collect data on fuel use characteristics. Data entry and cleaning was done in EPI INFO version 6.04, while data was analyzed using SPSS version 15.0. Analysis of variance, multiple linear regression and linear mixed model were used to isolate determining factors contributing to the variation of NO2 concentration.ResultsA total of 17,215 air samples were fully analyzed during the study period. Wood and crop were principal source of household energy. Biomass fuel characteristics were strongly related to indoor NO2 concentration in one-way analysis of variance. There was variation in repeated measurements of indoor NO2 over time. In a linear mixed model regression analysis, highland setting, wet season, cooking, use of fire events at least twice a day, frequency of cooked food items, and interaction between ecology and season were predictors of indoor NO2 concentration. The volume of the housing unit and the presence of kitchen showed little relevance in the level of NO2 concentration.ConclusionAgro-ecology, season, purpose of fire events, frequency of fire activities, frequency of cooking and physical conditions of housing are predictors of NO2 concentration. Improved kitchen conditions and ventilation are highly recommended.

Acute nitrogen dioxide inhalation induces mitochondrial dysfunction in rat brain

“…The NO 2 was diluted with fresh air at the intake port of the chamber to yield the desired NO 2 concentrations. The NO 2 within the chambers was measured every 30 min by the Saltzman colorimetric method using a spectrometer calibrated at 540 nm (Kumie et al, 2009). When not being treated, the rats had free access to food and water.…”

Acute nitrogen dioxide (NO2) exposure enhances airway inflammation via modulating Th1/Th2 differentiation and activating JAK-STAT pathway

“…The NO 2 gas was diluted with fresh air at the intake port of the chamber to yield desired concentrations; then, it was delivered to the animals through a tube positioned in the upper part of the chamber and distributed homogeneously via a fan. The NO 2 concentration within the chambers was measured every 30 min by a Saltzman colorimetric method using a spectrometer calibrated at 545 nm (Kumie et al, 2009). The exposure process sustained 5 h/day for 7 days.…”

In vivo screening to determine neurological hazards of nitrogen dioxide (NO2) using Wistar rats

“…The NO 2 gas was diluted with fresh air at the intake port of the chambers to yield desired concentrations. The NO 2 concentration within the chambers was measured every 30 min by a Saltzman colorimetric method using a spectrometer calibrated at 540 nm [1]. Rats from the four groups were weighed once a day throughout the experiment, and decapitated 18 h after the last exposure.…”

“…Due to the inhalation route of exposure, respiratory damage effect of NO 2 was always considered to be a key concern either in epidemiological or laboratory studies [1,[3][4][5][6], while other effects were always ignored. Recently, some epidemiological literatures linked NO 2 pollution with increasing risk of cardiovascular diseases and neurological disorders [7,8], which implied that lung is not the only target of NO 2 .…”

“…In the field, nitrogen dioxide (NO 2 ), a well-known indoor and outdoor pollutant, has been attracting more and more attention. People are widely exposed to NO 2 discharged from multiple sources including automobile exhaust, fossil fuel burning industries, gas cooking stoves, tobacco smoking and some others in occupational environment [1,2]. Peak levels of up to 0.4-4 parts per million (ppm) are encountered in the outdoors, particularly along kerbsides in downtown areas with heavy motor vehicular traffic [3,4].…”