Ambient air pollution is the single largest environmental health risk, estimated to be associated with several million deaths globally each year, mostly through exposure to fine particles <2.5µm (PM2.5). There are, however, differences in the size of the estimated health effects between different reports, depending on differences in methodology and assumptions. These differences risk inducing an impression of uncertainty about the health effects of air pollution, despite the overall strong scientific agreement that exists, and inhibit clear risk communication to the public and promotion of science-based policy recommendations. Effective and appropriate risk communication that promotes action is also difficult regarding environmental health risks where the risk to the individual is usually low even when the effect on the population is large. More efforts are thus needed to continuously improve the way the developed scientific knowledge is communicated and understood in different parts of the world, and how it can be used by policymakers and be understood by civil society. Additionally, changes in policies and recommendations do not always translate into action that promotes real-world changes in population exposure. Thus there is a need to come to a larger agreement on:
How to best estimate the health effects of air pollution and the resultant societal costs
How we improve the communication of health effects so as to promote action
How the health effect of air pollution can be decreased through policy measures, structural change, behavioural changes and other actions, and
How reductions in air pollution can move forward in a rapidly changing world.
Notes from the discussions
This workshop discussed these issues in four consecutive sessions.
The first part covered how the health impact of air pollution can be, and currently is, estimated. An introduction by the session chairs was followed by presentations by Bertil Forsberg, Zorana J. Anderssen and Pierpaolo Mudu, and an intense discussion in plenum. The second part of the session discussed how communication of health impacts can be improved to promote faster action on air pollution. Alberto Gonzalez Ortiz, Anne Stauffer (pre-recorded) and Roman Perez Velazco presented before the general discussion ensued. Following this, the third part of the session included presentations by Mike Holland, Ugo Taddei and Mikael Skou Anderssen, and a discussion on how we can reduce the health effects of air pollution through legislation, policy measures and structural or behavioural changes. In the fourth and final part Francesco Forastiere and Ebba Malmqvist started the discussion on “ways forward” with reflections and summaries of the day, before a final wrap-up session where the entire group of participants gave suggestions on conclusions and recommendations for the future.
The presentations and plenary discussions are here grouped around the following key words/topics:
Discussion of aspects for advancing the science on air pollution and health discussed during the session covered the following:
The need to target research on policy relevant questions including:
Links between air pollution and other stressors, such as traffic noise;
Consideration of both short-term and long-term effects.
The need to rigorously adhere to research protocols and to ensure good-quality peer review. Particular deficiencies were noted regarding a number of recently published systematic reviews. This problem needs to be acted on by journal editors.
The need for authors of epidemiological and other studies to recognize that results will be used in health impact assessment to inform policy development, and hence the need to consider the science-policy interface in the conclusions of published work.
Regarding Health Impact Assessment (HIA) of air pollution (quantification of effects, often to inform policy development), clarity is needed on the selection of counterfactual concentrations, concentration response-functions (CRFs, for which the most appropriate CRF based on type of exposure, quality, population etc. for the specific HIA should be selected, rather than just a meta-estimate), incidence data and other inputs. This will demonstrate that inputs are correctly aligned: there is for example sometimes inconsistent application of data on incidence or prevalence with response functions. This will also help to reduce confusion regarding variability in estimates and provide clearer policy-relevant messages. Care should be taken in selecting the first number presented since that is usually the information propagated in the media.
The steps involved in developing disease needs to be studied further, for example from the initiation of atherosclerosis and hypertension through to cardiovascular and other diseases and mortality.
‘Umbrella reviews’, such as those being carried out at the present time for WHO through HRAPIE2 (Health Response to Air Pollution in Europe) and EMAPEC (Estimating Morbidity from Air Pollution and its Economic Costs), should be carried out more regularly. In the ten years since the original HRAPIE study was concluded, the science of impact quantification has advanced considerably with respect to the range of impacts covered and the response functions used. Consistent sources of funding for this work need to be agreed.
Linked to this review work there is a need for guidance on how to perform and communicate burden of disease and impact assessment work (including guidance on what not to do). This work could perhaps be best done by model developers.
Methodological differences and complexities must not be allowed to obscure the fact that there is scientific consensus on the health effects of air pollution. Whilst there is variability in estimates of harm between sources, there is very good agreement that air pollution imposes a substantial health burden, on the pollutants involved and on the lack of thresholds for impact.
In addition, the need to be more open to citizen science was highlighted, to explore and better understand its potential, and to engage with stakeholders to address its limitations at an early stage.
Tools are already available for quantifying the health impacts of air pollution. These include WHO’s AirQ+ software (a new version of which was released on the day of the workshop in several languages) which allows quantification of the health impacts of air pollution, providing valuable decision-making support, including for countries where expertise is limited. Use of these tools should be promoted to ensure their wide uptake, by environmental and public health experts and for clean air advocacy.
Continued capacity building is necessary, including getting public health institutions on board. The tools available online seem likely to be particularly useful in the EECC countries and for FICAP.
A range of topics related to communication on air pollution and health were discussed during the session, reflecting the complexity of communication, and priorities for improving it. Emphasis was placed on the engagement of scientists either individually or through academic associations with other parties, such as local and national authorities including public health institutions and medical societies, and civil society, as well as the need to promote dissemination of new knowledge, available tools, and best practice examples of plans for addressing air pollution. Related to this, a strategy for better and more frequent engagement with journalists was recommended.
Communications within the community of those working in the field could be improved. For example, a portal for reviews of research work, including those in the pipeline, could be established. This would apply also to ensuring that the main messages on air pollution and health are coherent. Authors of scientific papers should include policy recommendations in their conclusions, this in turn requiring that they develop a good understanding of the direction of policy in their region. Training researchers on risk communication would be beneficial, particularly in the areas affected by the worst levels of air pollution.
While the details may vary, there are common messages that should be voiced unanimously and regularly, including that:
Air pollutants (PM, NO2, O3) are known to be bad for health, as reflected by an extensive academic literature that has been exposed to critical review.
Air pollution affects real people. (this message could be reinforced using personal testimonies)
These pollutants are each linked to a wide range of health impacts including mortality and chronic illness including heart and respiratory disease, dementia, stroke and type 2 diabetes.
Safe exposure limits (thresholds) have not been identified, with effects found to be associated to what we even now consider to be low concentrations.
Impacts of these pollutants on health are substantial.
Whilst further materials need to be developed, good communication materials are already available (such as HEAT) and should be used more widely with information tailored to the needs of different groups. Checks are needed to ensure that material intended to improve literacy on air pollution and health is pitched at an appropriate level for the intended audience, and to not discourage physical activity. Increased dissemination would benefit from translation of key texts, particularly those developed nationally, to a broader range of languages. This is particularly the case for infographics that provide clear illustration of the burden of air pollution on health, including diagrams that show:
The ways that air pollution affects health, both in terms of effects and the way that these effects develop with pollutant exposure
The need to control emissions even in areas where pollution levels are considered ‘low’ by reference to historic conditions
The benefits from existing and possible air pollution policy
The outputs of cost-benefit studies that demonstrate that action to reduce air pollution and protect health is ‘worth it’.
In addition, the value of communication ‘beyond numbers’, especially the importance of personal testimonies, the power of pictures, as well the use of positive examples and opportunities (the wider health benefits of reducing air pollution beyond estimates of mortality) was emphasized. Needs for further communication and advocacy were identified, with the involvement of civil society. This included the work on improving literacy on air pollution and health, better understanding of the mechanisms of air pollution effects on health, as well as simpler messaging of the estimates.
Further key messages concern the need to communicate the need for, and benefits of, policy on air pollution. There was a strong feeling that communication should promote positive messages, for example in relation to the benefits of action. Even the large estimates of health impact that often appear in the press can be turned to a positive – knowing that air pollution has a substantial impact on mortality provides evidence to support actions that we know will benefit health.
The group considered it to be important to ensure that effective communication on air pollution and health is available to all. It is important to strengthen interactions and cooperation between different parts of the UN/ECE region (and worldwide), in order to ensure equitable distribution of knowledge and of reliable information; featuring health in FICAP is recommended.
Environmental justice is an important aspect of the policy work on air pollution and health that requires action and improvement. Past analysis has tended to treat all people as equally at risk from air pollution and has not accounted for links between health and deprivation or considered variability in the risks faced by specific vulnerable groups such as young children or those with existing illness. Past work on impacts has focused on impacts most common in the elderly, such as death, type 2 diabetes and heart failure. More recognition needs to be given to impacts at the start of life, through pregnancy and into childhood. The effect of different policies, for example, control of emissions locally vs regionally, and the role of air quality limits compared to exposure reduction targets, needs to be evaluated in policy development.
Proper enforcement of legislation is required. Where that fails, litigation has been used successfully against governmental bodies in many areas of environment and health. There is still not enough recognition given in policy appraisal to the fact that those who are most disadvantaged are at the highest risk of harm from air pollution and other environmental risks.
More science-policy debate is needed at different levels to maximize the health benefits of action to control pollution, for example, to better understand:
Local contributions to air pollution for local action
Variation in vulnerability across the population linked to chronic health conditions and deprivation
The full range of available policy levers, such as the use of pricing as a tool (e.g., Euro Vignette) and
The policy implications of the links between air pollution and other stressors, e.g., to transport and then to climate, traffic noise, etc.
This final point highlights the importance of understanding the interactions between policies. Research has demonstrated strong co-benefits between policies to reduce air pollution and those focused on health, inequality, climate, transport and other areas. Recognizing and using these links improves the efficiency of the overall basket of measures being introduced and by doing so will enable health and ecological benefits, as reflected in the sustainable development goals, to be achieved more quickly. Inefficiency costs lives.
It was noted that policy tends to be developed on an incremental basis, considering current conditions and how they can be adjusted to bring down pollution levels. An alternative approach would be to define an alternative baseline, where at some point in the future we want to cover air quality, climate, mobility, equality, etc., and consider what society would look like to achieve this goal. This may bring in a number of efficiency benefits, for example, building in greener infrastructure and behavioural change. It could also shift responsibility for health effects of pollution away from affected individuals.
Further action is also needed to ensure availability of policy relevant reviews/updates of the scientific work. This requires formulation and establishment of clear responsibilities in terms of planning, science reviews, etc. WHO has been identified as the appropriate body for such reviews; however, this is conditional on securing sustainable resources to support that work.
The WHO Air Quality Guidelines (AQGs) demonstrate high confidence in observations that impacts occur even at what were previously considered very low concentrations. However, it must be recognized that they do not represent thresholds for effects, and hence that benefits of reducing air pollution will continue even below the WHO AQGs. Some in the group expressed a preference for policy based on limit values rather than exposure reduction targets, as the former are easier to measure and were felt more appropriate for reducing inequalities. However, this view was not shared by all present and others considered that the two could work in harmony. Care is, however, needed in the precise design of exposure reduction targets.
Whilst it is acknowledged that further research and debate will be informative it is also necessary to recognize the human cost of delays to action. Reducing health impacts of air pollution for the current population, young and old, requires that action is taken urgently.
Conclusions and recommendations
Concentrate communication to policymakers, civil society, and the public on the findings where there is overall scientific consensus
Despite ongoing scientific developments, there are no doubts about serious health effects and no safe levels, and this overall consensus and the main effects should be emphasized rather than uncertainties about details. Clear messaging improves the possibility for decision-makers to act.
Recipients: TFH, assisted by all parties to the Air Convention, including stakeholders such as NGOs. In addition: the air pollution scientific community, all levels of governments, including local (city) governments. However, responsibility lies with all organizations endowed with communication departments, journalists, academia and NGOs etc.