User guide

User Guide for the Air and Health Atlas

The Outdoor Air and Health Atlas is a web-based platform that collects and organizes the available evidence on the relationship between air quality and population health. Through data, indicators, maps, and interactive tools, the Atlas enables users to explore the impacts of air pollution, territorial differences, and the characteristics of the most exposed populations. This guide supports users in navigating the platform by describing its structure, content, and functionalities, with the aim of promoting the correct interpretation of data and the informed use of the information provided.

The Atlas website consists of two main sections:

• Explanatory: an introductory section providing a summary of current knowledge on the health impacts of air pollution, together with an explanation of the sources of information presented in the Atlas. This section also includes links to documents describing the methodologies in greater detail;
• Exploratory: an interactive section that allows users to query the available data sources and obtain:
  • maps of population-weighted exposure to PM_2.5 and NO₂, based on annual average pollutant concentrations and resident population data;
  • maps of mortality attributable to current levels of air pollution and under future pollutant reduction scenarios.

The website landing page provides access to both the map exploration section and the section containing methodological and scientific information. Users can also scroll down the page to view the Explanatory section of the website.

Explanatory Page

(1) Map of pollutant concentration

In the methodological section, the page presents a series of questions and answers that provide a concise overview of the process leading from the measurement of air pollutant concentrations to the quantification of health effects. The first map illustrates the initial step of this process. By scrolling down the page, users can access the second map, which displays pollutant concentrations.

(2) Map of population distribution

As users continue scrolling through the page, they reach the third map, which illustrates the distribution of the population across the territory. A navigation indicator on the left-hand side shows their current position within the storytelling pathway.

(3) Map of weighted exposition

As users continue scrolling, they are introduced to the methodology used to calculate population-weighted exposure, followed by a map visualizing this indicator.

(4) Map of cardiovascular mortality

Continuing further down the page, users encounter an additional question-and-answer section. The accompanying map shows the spatial distribution of deaths due to cardiovascular diseases, providing an example of the geographic distribution of a health outcome that is known to be associated with air pollution exposure.

(5) Map of attributable mortality

Continuing down the page, users encounter a map showing attributable deaths and a description of the method used to derive this measure, based on a counterfactual scenario in which pollutant concentrations are assumed to meet the limits recommended by the World Health Organization. 

(6) and (7) Useful instructions

Once the rationale underlying the calculation has been explained, further scrolling reveals brief instructions on how to use the Atlas in two steps.

After completing the vertical scrolling through these sections, users are once again presented with the options to access the Explore the Maps and Read the Methodology sections.

Exploratory Page

(1) First screen

Upon entering the Explore section, users are presented with a dashboard containing a set of filters that can be used to generate the desired map. By default, the page displays a map of Italy showing the total number of deaths attributable to PM_2.5 for the most recent year available.

In the upper-left panel, users can select different metrics, including population-weighted exposure and attributable deaths; the level of geographical aggregation (municipality, province, or region), the pollutant of interest (PM_2.5or NO₂), and, when the selected metric is attributable deaths, the health outcome of interest (all-cause natural mortality, cardiovascular mortality, respiratory mortality, or lung cancer mortality).

In the lower-left panel, users can select among different future scenarios. At the bottom centre of the page, a timeline displays the trend of the selected indicator from 2016 to the present. The timeline also includes projections based on the chosen scenario. By moving the cursor along the timeline, users can visualize the map for a specific year in the past, showing the estimated attributable fraction based on the pollutant levels recorded in that year or for a future year, according to the selected scenario.

In the upper-right corner, a summary panel presents key figures related to the map being displayed. By default, information is shown for Italy as a whole; however, by entering a location in the search box, users can view data for a specific municipality, province, or region. The panel reports the total number and percentage of attributable deaths, as well as the distribution of population-weighted exposure across Italian municipalities.

When a specific geographical area is selected, the displayed information is updated accordingly, and the histogram indicates the position of the selected municipality within the overall distribution of Italian municipalities.

(2) Detail example (3) Choosing a future scenario

Moving the cursor over the dashboard drop-down menus displays brief definitions of the technical terms used throughout the Atlas.

Users can also select a municipality directly from the map by hovering over it and clicking on it. This produces the same visualizations and information that would be obtained by entering the municipality's name in the search box.

Zooming in on the map provides a more detailed view of the selected area.

To define future air pollution reduction scenarios, users are offered two options:

• To select one of the European Union targets, which also represents the default scenario, or the WHO 2021 Air Quality Guidelines target;
• To define a custom scenario by selecting a target pollutant concentration and the calendar year by which that concentration should be achieved.

Clicking on “Atlante Aria salute” in the top-left corner, the user returns to the Explanatory section.