Assessing the human health risks of outdoor air pollution
Updated on 30/11/2017
Outdoor air (ambient air), Pollens, Allergy, Pesticides
The effects on health and the environment of ambient air pollution from a large number of chemical pollutants have been well understood for a number of years now. It is now clearly established that current ambient air pollution levels have an impact on health, in particular respiratory and cardiovascular health. The Agency has been involved in the issue of outdoor air pollution and its impact on human health for many years, and it conducts a wide range of scientific assessment work on this topic.
Pollens and allergies
Over the last few decades, allergies have become increasingly prevalent in the population in several countries, and especially France. The number of people suffering from allergies has more than doubled in the last twenty years. Pollen allergies (hay fever or pollinosis) currently affect 15 to 20% of the French population.
Due to global warming and increased quantities of carbon dioxide in the atmosphere, the amounts of pollen released into the air are expected to increase over the coming decades and new varieties of pollen may appear in regions where they had not hitherto been found. Furthermore, atmospheric pollutants resulting from human activities can modify pollen grains by breaking down their outer walls, facilitating the liberation of allergens. Pollen thus modified has a much higher allergenicity. At the same time, certain chemical pollutants can exacerbate the sensitivity of allergic subjects, making them more sensitive to pollen.
In 2013, ANSES produced a full report on the current state of knowledge of pollen in ambient air. This assessment work has shown that:
The most problematic pollens in France come from true grasses, birch trees, ragweed and the cypress (Cupressaceae) family of trees (including cypress, thuya and juniper, for example),
It is not currently possible to determine a level at which effects will appear for a given type of pollens, due to the fact that the dose-response relationship involves numerous factors, such as the pollen's allergenicity, individual sensitivity, etc.,
Climate change may influence pollinisation dates in a number of plant species, prompting it to begin earlier and therefore prolonging the pollinisation period.
Pollen concentrations in ambient air in France are currently monitored by the National aerobiological monitoring network (RNSA). In ANSES's recommendations, the Agency emphasises the need for permanent monitoring of airborne pollen.
In addition, ANSES is now drafting a report on the current state of knowledge regarding pollen and mould in ambient air in those French overseas regions and départements with the greatest health concerns. This was done at the request of the Ministries of Health and of the Environment as part of the pollinosis prevention activities of the 3rd French Environment & Health Action Plan (2015-2019). The goal is also the provide scientific and technical recommendations for metrological surveillance, for locating and supporting allergy sufferers, for informing the general public as well as professionals (healthcare workers, etc.) and for implementing prevention initiatives to reduce exposure and its impact on health.
Pesticides in ambient air
Many types of exposure can be caused by pesticide use. While dietary exposure is now increasingly well documented, knowledge on exposure of the general population to pesticides via air remains fragmentary, particularly in the absence of specific regulations on the monitoring of pesticides in ambient air.
Because of this, and in the framework of the new National Environmental Health Action Plan (PNSE 2015-2019), ANSES received a formal request from the Ministries of Agriculture, Ecology, Health and Labour to conduct a collective expert appraisal with the aim of proposing the arrangements for implementing national surveillance of pesticides in ambient air in metropolitan France and the overseas départements and regions (DROM). Based on a list of 90 priority substances, this national surveillance should make it possible to assess the chronic exposure of the general population and the associated health risks. The results of this surveillance will be used by the Central Laboratory for Air Quality Monitoring (LCSQA), in connection with several approved air quality monitoring associations (AASQAs), in order to define the protocol for an exploratory one-year campaign that will start in 2018.
In addition to this national surveillance, the Agency recommends setting up specific measurement campaigns to assess the exposure of populations living in the vicinity of sources of pesticide emissions, in particular residents in agricultural areas.
The data obtained from these campaigns will also be used in the framework of ANSES's phytopharmacovigilance scheme, whose aim is to monitor the adverse effects of plant protection products available on the market.
This work is an extension of the review of knowledge regarding the presence of pesticide residues in the atmospheric compartment and in indoor environments that the Agency launched in 2008 for the French Observatory for Pesticide Residues (ORP). This work ended in October 2010 with the publication of a report on "Recommendations and outlook for national monitoring of pesticide contamination of the air".
Urban atmospheric pollution: ambient air particles and their chemical make-up
Numerous studies have concluded that urban atmospheric pollution has an effect on public health. According to recent French data from the Aphekom project carried out in nine French cities, life expectancy at the age of 30 could be increased by 3.6 to 7.5 months, depending on the city, delaying almost 3000 deaths per year, if mean annual concentrations of PM2.5 particles met WHO guideline values (10 μg/m3).
In June 2012, the International Agency for Research on Cancer (IARC) classified diesel engine exhaust as carcinogenic to humans (Group 1), and in 2013 it also classified outdoor air pollution and the suspended particles in ambient air in this same group.
Questions remain regarding the health effects potentially related to the composition of particulate aerosols, whose make-up over the last few years has most likely evolved.
Due to this, and in order to provide management support, ANSES is conducting scientific studies in order to evaluate toxicological and epidemiological data on chemical composition and particle size.
More specifically, as concerns "road traffic" as a pollution source, ANSES will be working to establish the retrospective and prospective evolution of particle emissions, based on the French vehicle population and cycles close to real use, through the consideration of various scenarios, and to identify the differentiated impacts of environmental remediation technologies on particulate emissions from traffic. This information can then be compared with the emission data available for other sources of particulate matter.
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