Nitrogen Oxides Levels in the Atmosphere of Different Brazilian Urban Centers, by Passive Sampling

Urban air pollution is still an emerging environmental problem, it causes damage to health and is difficult to be controlled in urban centers. The population of large metropolises is often exposed to concentrations of nitrogen oxides (NOx), mainly due to vehicle emissions. Epidemiological studies claim that exposure to these oxides is strongly correlated with the incidence of different types of cancer. This work evaluated the impact of NOx emissions on the air quality of five Brazilian urban centers, using passive sampling. The NO/NO2 ratio indicated photochemical aging in the atmosphere of all the cities studied. Although there has been a predominant trend towards decreasing of nitrogen oxides concentrations in many locations, average annual values > 40 mu g m(-3) NO2 have been found, in Brazil as well as other parts of the world, what indicates the need to control air pollution in these areas.

Automated summary

Urban air pollution caused by vehicle emissions, especially nitrogen oxides (NOx), is an emerging environmental problem that affects health and is difficult to control. A study in Brazil evaluated the impact of NOx emissions on air quality in five urban centers, finding signs of photochemical aging in the atmosphere. Despite a decreasing trend in many locations, the need to control air pollution in these areas is emphasized by high annual NO2 values exceeding 40 µg m(-3) found in Brazil and other parts of the world.