La pollution atmosphérique et ses effets sur la santé respiratoire. Document d’experts du groupe pathologies pulmonaires professionnelles environnementales et iatrogéniques (PAPPEI) de la Société de pneumologie de langue française (SPLF)

Low-Temperature O3 Decomposition over Pd-TiO2 Hybrid Catalysts

In aircraft and spacecraft, outside air is not directly fed to the passenger because it contains ozone at elevated altitudes. The decomposition of low concentration ozone in the air was carried out at 25 °C by catalytic oxidation on Pd-based catalysts supported on a high surface area hybrid TiO2. The use of these hybrid catalysts has shown a beneficial effect, both on the catalytic activity and on the catalyst stability. Kinetic studies showed that the most promising catalytic phase (Pd/TiO2_100) was the one obtained from the TiO2 support containing the lowest content of citrate ligands and leading to small Pd particles (around 4 nm). The effect of catalyst synthesis on the decomposition of O3 gas (15 ppm) in a dry and humid (HR = 10%) stream in a closed environment such as aircraft or spacecraft was also investigated in this study and further elucidated by detailed characterizations. It was shown that the system could be used as an effective treatment for air coming from outside.

[The effect of air pollution in diffuse interstitial lung disease]

Few studies have examined the effects of air pollution in diffuse interstitial lung disease and they have focused on small numbers of patients. Most data are available in idiopathic pulmonary fibrosis and studies suggest that the level of exposure to pollutants may influence the development of acute exacerbations (ozone and NO₂), their incidence (NO₂), decline in respiratory function (PM₁₀) and death (PM₁₀ and PM_2.5). Several studies show an increase in the incidence of rheumatoid arthritis in people living near busy roads. In systemic scleroderma, hypersensitivity pneumonitis and sarcoidosis although negative effects of pollution have been reported the data are insufficient to be conclusive. Nevertheless, the observed effects of air pollution are consistent with those described for other chronic respiratory diseases. Exposure to pollution induces oxidative stress, chronic inflammation and shortening of telomeres, which are all mechanisms described in fibrogenesis. New epidemiological studies are needed with individual measurements of exposure to outdoor and indoor pollution, as well as fundamental studies to clarify the effect of pollution on fibrogenesis.

[Evolution of urban air pollution in metropolitan France between 2008 and 2015]

BACKGROUND

Air pollution is a major public health issue and remains a major concern in France and around the world. Proof of this is that air pollution is one of the first environmental concerns of the French population. The purpose of this study was to establish a system for monitoring the actual concentrations of different atmospheric pollutants observed in major French cities.

METHOD

For 13 major cities in Metropolitan France we collected data from the measurement stations of Air Quality Monitoring agencies for various pollutants: NO₂, O₃, PM₁₀, PM_2.5. Using these data, we have produced monthly time series of these pollutants covering the period 2008-2015. We also calculated the slopes of these time series as well as the correlation coefficients.

RESULTS

The results do not show trends that are decreasing but rather stagnating, for the air pollutants considered. Our work therefore indicates that monitoring and taking steps to reduce air pollution must be increased.