A/HRC/40/55 61. There are seven key steps that States must take in fulfilling the right to breathe clean air: monitor air quality and impacts on human health; assess sources of air pollution; make information publicly available, including public health advisories; establish air quality legislation, regulations, standards and policies; develop air quality action plans at the local, national and, if necessary, regional levels; implement an air quality action plan and enforce the standards; and evaluate progress and, if necessary, strengthen the plan to ensure that the standards are met. 62. At each of these stages, States must ensure that the public is fully informed and has an opportunity to participate in decision-making processes. Extra effort should always be made to reach out to women, children and others in vulnerable situations whose voices are too often not heard in environmental policy processes. States must pay special attention to environmental defenders working to protect the right to clean air. A. Monitoring air quality and health effects 63. States must establish networks and programmes to monitor air quality and health effects, particularly in urban areas and other regions known to suffer from poor air quality. Direct monitoring data can be complemented by air quality observations from satellites and outputs from computer models. Monitoring is a prerequisite to fulfilling a State’s obligation to provide information to the public and is also essential to informed policy-making. 64. Most high-income countries operate extensive air quality monitoring networks providing continuous, hourly measurements of pollution levels. However, these networks are less common or provide less comprehensive coverage in low- and middle-income countries where air quality is generally worse. Some countries, particularly in Africa, have no air quality monitoring stations at all. Several States with severe air quality problems, such as China and India, have made great strides in recent years in establishing hundreds (India) and thousands (China) of new air quality monitoring stations. 65. New technologies offer the possibility of leapfrogging expensive air quality monitoring stations. Stationary and dynamic networks of low-cost sensors are much less expensive. Air pollution sensors can be deployed on cell phones, drones and vehicles by Governments, citizens, communities and businesses. Networks of these devices, integrated with satellite data and modelling, could complement regulatory monitoring and help identify air pollution hotspots. However, questions regarding the reliability and consistency of low-cost sensors need to be addressed by standards and protocols. B. Assessing the sources of air pollution 66. Reducing the disease burden attributable to air pollution and fulfilling the right to clean air require understanding the types of pollution and major contributing sources. This is critical for identifying the highest priority and most cost-effective actions for controlling emissions to protect public health, human rights and the environment. Source assessments have been completed in many high-income nations, as well as in China and India, although there is substantial uncertainty regarding emissions from the large informal sectors in these economies.31 Modelling and forecasting inform estimates of exposure and health impacts, provide a basis for air quality advisories and identify measures needed to control specific emissions. Without adequate information, designing effective policies, programmes and other interventions is impossible. C. Public reporting on air quality 67. In addition to systematically collecting air quality information, States must share this information in a timely, accessible way, educate the public about the health risks posed by 31 Health Effects Institute, State of Global Air 2018: A Special Report on Global Exposure to Air Pollution and its Disease Burden (Boston, 2018). 11